1. Introduction.. 2

2. Radioactive waste. Origin and classification. 4

2.1 Origin of radioactive waste. 4

2.2 Classification of radioactive waste. 5

3. Disposal of radioactive waste. 7

3.1. Disposal of radioactive waste in rocks Oh. 8

3.1.1 Main types and physical and chemical characteristics of rocks for nuclear waste disposal. 15

3.1.2 Selecting a radioactive waste disposal site. 18

3.2 Deep geological disposal of radioactive waste. 19

3.3 Near-surface disposal. 20

3.4 Rock melting21

3.5Direct injection22

3.6 Other methods of disposal of radioactive waste23

3.6.1 Removal at sea23

3.6.2 Removal under the seabed... 23

3.6.3 Removal into movement zones. 24

3.6.4 Burial in ice sheets.. 25

3.6.5 Delete in outer space.. 25

4. Radioactive waste and spent nuclear fuel in the Russian nuclear power industry. 25

5. Problems of the radioactive waste management system in Russia and possible ways to solve it... 26

5.1 Structure of the radioactive waste management system in the Russian Federation.. 26

5.2 Proposals for changing the doctrine of radioactive waste management.. 28

6. Conclusion.. 29

7. List of used literature: 30

1. Introduction

The second half of the twentieth century was marked by a sharp aggravation environmental problems. The scale of mankind's technogenic activity is currently comparable to geological processes. To previous types of pollution environment, which have received extensive development, a new danger of radioactive contamination has been added. The radiation situation on Earth over the past 60-70 years has undergone significant changes: by the beginning of the Second World War, in all countries of the world there were about 10-12 g of radiation received in pure form natural radioactive substance - radium. Nowadays, one medium-power nuclear reactor produces 10 tons of artificial radioactive substances, most of which, however, are short-lived isotopes. Radioactive substances and sources of ionizing radiation are used in almost all industries, in healthcare, and in conducting a wide variety of scientific research.

Over the past half century, tens of billions of curies of radioactive waste have been generated on Earth, and these numbers are increasing every year. The problem of disposal and disposal of radioactive waste is particularly acute. nuclear power plants is now becoming the time for dismantling the majority of nuclear power plants in the world (according to the IAEA, these are more than 65 nuclear power plant reactors and 260 reactors used for scientific purposes). There is no doubt that the most significant volume of radioactive waste was generated on the territory of our country as a result of the implementation of military programs for more than 50 years. During creation and improvement nuclear weapons One of the main tasks was the rapid production of nuclear fissile materials that give a chain reaction. Such materials are highly enriched uranium and weapons-grade plutonium. The largest above-ground and underground storage facilities for radioactive waste have formed on Earth, representing a huge potential danger for the biosphere for many hundreds of years.

http://zab.chita.ru/admin/pictures/424.jpgThe issue of radioactive waste management requires an assessment various categories and their storage methods, as well as different environmental requirements. The goal of disposal is to isolate waste from the biosphere for extremely long periods of time, ensuring that residual radioactive substances reaching the biosphere will be in negligible concentrations compared, for example, with natural background radioactivity, and also providing confidence that the risk from careless human intervention will be very small. Geological disposal has been widely proposed to achieve these goals.

However, there are many different proposals regarding methods for disposing of radioactive waste, for example:

· Long-term above-ground storage,

· Deep wells (at a depth of several km),

Rock melting (suggested for heat-generating waste)

· Direct injection (suitable for liquid waste only),

· Removal at sea,

· Removal under ocean floor,

· Removal into movement zones,

· Removal into ice sheets,

· Removal into space

Some proposals are still being developed by scientists different countries world, others have already been banned international agreements.Most scientists researching this problem, recognize the most rational possibility of burying radioactive waste in the geological environment.

RAO problem - component"Agenda 21" adopted at the World Summit on top level on Earth Issues in Rio de Janeiro (1992) and the “Program of Action for the Further Implementation of Agenda 21” adopted by the Special Session General Assembly United Nations (June 1997). The latest document, in particular, outlines a system of measures to improve methods of managing radioactive waste, to expand international cooperation in this area (exchange of information and experience, assistance and transfer of relevant technologies, etc.), to tighten the responsibility of states for ensuring the safe storage and disposal of radioactive waste.

In my work I will try to analyze and evaluate the disposal of radioactive waste in the geological environment, as well as the possible consequences of such disposal.

2. Radioactive waste. Origin and classification.

2.1 Origin of radioactive waste.

Radioactive waste includes materials, solutions, gaseous media, products, equipment, biological objects, soil, etc. that are not subject to further use, in which the content of radionuclides exceeds the established levels regulations. Spent nuclear fuel (SNF) may also be included in the “RAW” category if it is not subject to subsequent processing in order to extract components from it and, after appropriate storage, is sent for disposal. RW is divided into high-level waste (HLW), intermediate-level waste (ILW) and low-level waste (LLW). The division of waste into categories is established by regulations.

Radioactive waste is a mixture of stable chemical elements and radioactive fragmentation and transuranium radionuclides. Fragmentation elements numbered 35-47; 55-65 are fission products nuclear fuel. During 1 year of operation of a large power reactor (when loading 100 tons of nuclear fuel with 5% uranium-235), 10% (0.5 tons) of fissile material is produced and approximately 0.5 tons of fragmentation elements are produced. Nationwide, 100 tons of fragmentation elements are produced annually at nuclear power reactors alone.

Main and the most dangerous for the biosphere, the elements of radioactive waste are Rb, Sr, Y, Zr, Mo, Ru, Rh, Pd, I, Cs, Ba, La....Dy and transuranic elements: Np, Pu, Am and Cm. Solutions of radioactive waste with high specific activity in composition are mixtures of nitrate salts with a concentration nitric acid up to 2.8 mol/liter, they contain additives HF(up to 0.06 mol/liter) and H2SO4(up to 0.1 mol/liter). The total content of salts of structural elements and radionuclides in solutions is approximately 10 wt%. Transuranium elements are formed as a result of the neutron capture reaction. In nuclear reactors, fuel (enriched natural uranium) is in the form of tablets UO 2 placed in tubes made of zirconium steel (fuel element - TVEL). These tubes are located in the reactor core; between them are placed moderator blocks (graphite), control rods (cadmium) and cooling tubes through which the coolant circulates - most often, water. One load of fuel rods lasts approximately 1-2 years.

Radioactive waste is generated:

During the operation and decommissioning of nuclear fuel cycle enterprises (mining and processing of radioactive ores, manufacturing of fuel elements, electricity generation at nuclear power plants, reprocessing of spent nuclear fuel);

In the process of implementing military programs for the creation of nuclear weapons, conservation and liquidation of defense facilities and rehabilitation of territories contaminated as a result of the activities of enterprises producing nuclear materials;

During the operation and decommissioning of ships of the naval and civil fleets with nuclear power plants and their maintenance bases;

When using isotope products in the national economy and medical institutions;

As a result of nuclear explosions in the interests national economy, during mining, during space programs, as well as during accidents at nuclear facilities.

When radioactive materials are used in medical and other research institutions, a significantly smaller amount of radioactive waste is generated than in the nuclear industry and the military-industrial complex - this is several tens of cubic meters of waste per year. However, the use of radioactive materials is expanding, and with it the volume of waste is increasing.

2.2 Classification of radioactive waste

RW is classified according to various criteria (Fig. 1): state of aggregation, by composition (type) of radiation, by lifetime (half-life T 1/2), by specific activity (radiation intensity). However, the classification of radioactive waste used in Russia by specific (volume) activity has its disadvantages and positive aspects. The disadvantages include the fact that it does not take into account the half-life, radionuclide and physico-chemical composition of the waste, as well as the presence of plutonium and transuranium elements in them, the storage of which requires special stringent measures. On the positive side is that at all stages of radioactive waste management, including storage and disposal, the main task is to prevent environmental pollution and over-exposure of the population, and the separation of radioactive waste depending on the level of specific (volume) activity is precisely determined by the degree of their impact on the environment and humans. The measure of radiation hazard is influenced by the type and energy of radiation (alpha, beta, gamma emitters), as well as the presence of chemically toxic compounds in waste. The duration of isolation from the environment for intermediate-level waste is 100-300 years, for high-level waste - 1000 years or more, for plutonium - tens of thousands of years. It is important to note that radioactive waste is divided depending on the half-life of radioactive elements: short-lived, with a half-life of less than a year; medium-lived from a year to a hundred years and long-lived more than a hundred years.

Fig.1 Classification of radioactive waste.

Among radioactive waste, the most common ones in terms of their state of aggregation are liquid and solid. To classify liquid radioactive waste, the specific (volume) activity parameter (Table 1) was used. Liquid radioactive waste liquids in which the permissible concentration of radionuclides exceeds the concentration established for water in open reservoirs are considered. Every year, nuclear power plants generate large amounts of liquid radioactive waste (LRW). Basically, most liquid radioactive waste is simply dumped into open water bodies, since their radioactivity is considered safe for the environment. Liquid radioactive waste is also generated at radiochemical enterprises and research centers.

Table 1. Classification of liquid radioactive waste

Of all types of radioactive waste, liquid ones are the most common, since both the substance of structural materials (stainless steels, zirconium fuel rod shells, etc.) and technological elements (salts) are transferred into solutions alkali metals etc.). Most of the liquid radioactive waste is generated by nuclear energy. Spent fuel rods, combined into single structures - fuel assemblies, are carefully removed and kept in water in special settling pools to reduce activity due to the decay of short-lived isotopes. Over three years, activity decreases by about a thousand times. Then the fuel rods are sent to radiochemical plants, where they are crushed with mechanical shears and dissolved in hot 6-N nitric acid. A 10% solution of liquid high-level waste is formed. About 1000 tons of such waste are produced per year throughout Russia (20 tanks of 50 tons each).

For solid radioactive waste the type of dominant radiation and exposure dose rate directly on the surface of the waste were used (Table 2).

Table 2. Classification of solid radioactive waste

Solid radioactive waste is the form of radioactive waste that is directly subject to storage or disposal. There are 3 main types of solid waste:

residues of uranium or radium not extracted during ore processing,

artificial radionuclides generated during the operation of reactors and accelerators,

exhausted resources, dismantled reactors, accelerators, radiochemical and laboratory equipment.

For classification gaseous radioactive waste the specific (volume) activity parameter is also used, Table 3.

Table 3. Classification of gaseous radioactive waste

Categories of radioactive waste	Volume activity, Ci/m 3
Low activity	below 10 -10
Moderately active	10 -10 - 10 -6
Highly active	above 10 -6

Gaseous radioactive waste is formed mainly during the operation of nuclear power plants, radiochemical fuel regeneration plants, as well as during fires and other emergencies at nuclear facilities.

This is a radioactive isotope of hydrogen 3 H (tritium), which is not retained by the stainless steel cladding of fuel elements, but is absorbed (99%) by the zirconium cladding. In addition, the fission of nuclear fuel produces radiogenic carbon, as well as the radionuclides krypton and xenon.

Inert gases, primarily 85 Kr (T 1/2 = 10.3 years), are supposed to be captured at radiochemical industry enterprises, isolating it from exhaust gases using cryogenic technology and low-temperature adsorption. Gases with tritium are oxidized to water, and carbon dioxide, in which radiogenic carbon is present, is chemically bound in carbonates.

3. Disposal of radioactive waste.

The problem of safe disposal of radioactive waste is one of those problems on which the scale and dynamics of nuclear energy development largely depend. The general task of safe disposal of radioactive waste is the development of methods for isolating them from the biocycle that will eliminate the negative environmental consequences for humans and the environment. The ultimate goal of the final stages of all nuclear technologies is the reliable isolation of radioactive waste from the biocycle for the entire period of radiotoxicity remaining in the waste.

Currently, technologies for the immobilization of radioactive waste are being developed and various methods of their disposal are being studied, the main criteria for choosing which for widespread use are the following: – minimizing the costs of implementing measures for radioactive waste management; – reduction of generated secondary radioactive waste.

For recent years a technological basis has been created for modern system RW management. IN nuclear countries There is a full range of technologies that allow efficient and safe processing of radioactive waste, minimizing its quantity. IN general view the chain of technological operations for handling liquid radioactive waste can be presented in the following form: However, nowhere in the world has a method of final disposal of radioactive waste been chosen; the technological cycle of radioactive waste management is not closed: solidified liquid radioactive waste, as well as solid radioactive waste, are stored at special controlled sites, creating a threat to the radioecological situation of the storage sites.

3.1. Disposal of radioactive waste in rocks

Thus, when solving the problem of radioactive waste disposal, the use of “experience accumulated by nature”, can be seen especially clearly. It is not for nothing that specialists in the field of experimental petrology were perhaps the first who were ready to solve the problem that arose.

They make it possible to isolate radioactive waste from a mixture of elements separate groups, similar in their geochemical characteristics, namely:

· alkaline and alkaline earth elements;

· halides;

· rare earth elements;

· actinides.

For these groups of elements, you can try to find rocks and minerals that are promising for their binding .

Natural chemical (and even nuclear) reactors that produce toxic substances, is not news in the geological history of the Earth. An example is the Oklo deposit, where ~ 200 million years ago, for 500 thousand years, at a depth of ~ 3.5 km, a natural reactor operated, heating the surrounding rocks to 600°C. The preservation of most radioisotopes at the site of their formation was ensured by their isomorphic inclusion in uraninite. The dissolution of the latter was prevented by the recovery situation. Nevertheless, about 3 billion years ago, life arose on the planet, successfully coexists next to very dangerous substances, and develops.

Let us consider the main ways of self-regulation of nature from the point of view of their use as methods of neutralizing waste from man-made activities of mankind. Four such principles are outlined.

a) Isolation - harmful substances are concentrated in containers and protected by special barrier substances. Waterproof layers can serve as a natural analogue of containers. However, this is not a very reliable way to neutralize waste: when stored in an isolated volume hazardous substances retain their properties and, if the protective layer is violated, can break out into the biosphere, killing all living things. In nature, the rupture of such layers leads to emissions of toxic gases (volcanic activity accompanied by explosions and emissions of gases, hot ash, emissions of hydrogen sulfide when drilling wells for gas - condensate). When storing hazardous substances in special storage facilities, sometimes the insulating shells with catastrophic consequences. A sad example from man-made human activity is the Chelyabinsk release of radioactive waste in 1957 due to the destruction of storage containers. Isolation is used for temporary storage of radioactive waste; in the future, it is necessary to implement the principle of multi-barrier protection during their burial; one of the components of this protection will be an insulation layer.

b) Dispersion - dilution of harmful substances to a level that is safe for the biosphere. In nature, V.I. Vernadsky’s law of universal dispersion of elements operates. As a rule, the lower the clarke, the more dangerous the element or its compounds (rhenium, lead, cadmium) to life. The higher the clarke of an element, the safer it is - the biosphere is “accustomed” to it. The principle of dispersion is widely used when discharging man-made harmful substances into rivers, lakes, seas and oceans, as well as into the atmosphere through smokestacks. Scattering can be used, but apparently only for those compounds whose lifetime is within natural conditions small, and which will not be able to give harmful products decay. In addition, there should not be many of them. So, for example, CO 2 is, generally speaking, not harmful, and sometimes even useful. However, an increase in carbon dioxide concentration throughout the atmosphere leads to greenhouse effect and thermal pollution. Substances (for example, plutonium) produced artificially in large quantities. Dispersion is still used to remove low-level waste and, based on economic feasibility, will remain one of the methods for their neutralization for a long time. However, in general, at present, the possibilities of dispersion have largely been exhausted and it is necessary to look for other principles.

c) The existence of harmful substances in nature in chemically stable forms. Minerals in earth's crust persist for hundreds of millions of years. Common accessory minerals (zircon, sphene and other titano- and zirconosilicates, apatite, monazite and other phosphates, etc.) have a large isomorphic capacity with respect to many heavy and radioactive elements and are stable in almost the entire range of petrogenesis conditions. There is evidence that zircons from placers, which, together with the host rock, experienced processes of high-temperature metamorphism and even granite formation, retained their primary composition.

d) Minerals, c crystal lattices in which the elements to be neutralized are located, under natural conditions they are in balance with the environment. Reconstruction of the conditions of ancient processes, metamorphism and magmatism, which took place many millions of years ago, is possible due to the fact that in crystalline rocks, over a long geological time scale, the compositional features of the minerals formed under these conditions and being in thermodynamic equilibrium with each other are preserved.

The principles described above (especially the last two) are used in the neutralization of radioactive waste.

Existing IAEA developments recommend the disposal of solidified radioactive waste in stable blocks of the earth's crust. The matrices should interact minimally with the host rock and not dissolve in pore and fracture solutions. The requirements that matrix materials must satisfy for binding fragmentation radionuclides and small actinides can be formulated as follows:

The ability of the matrix to bind and retain in the form of solid solutions is possible larger number radionuclides and their decay products over a long (geological scale) time.

· Be a material that is resistant to physical and chemical weathering processes under burial conditions (long-term storage).

· Be thermally stable at high radionuclide contents.

· Possess a complex of physical- mechanical properties, which any matrix material must have to ensure the processes of transportation, burial, etc.:

o mechanical strength,

o high thermal conductivity,

o low coefficients of thermal expansion,

o resistance to radiation damage.

· Have a simple production flow chart

· Produced from raw materials of relatively low cost.

Modern matrix materials are divided according to their phase state into glassy (borosilicate and aluminophosphate glasses) and crystalline - both polymineral (synrocks) and monomineral (zirconium phosphates, titanates, zirconates, aluminosilicates, etc.).

Traditionally, glass matrices (borosilicate and aluminophosphate in composition) were used for the immobilization of radionuclides. These glasses are close in their properties to aluminosilicate glasses, only in the first case aluminum is replaced by boron, and in the second case silicon is replaced by phosphorus. These replacements are caused by the need to reduce the melting temperature of melts and reduce the energy intensity of the technology. Glass matrices reliably retain 10-13 wt.% of radioactive waste elements. In the late 70s, the first crystalline matrix materials were developed - synthetic rocks (synroc). These materials consist of a mixture of minerals - solid solutions based on titanates and zirconates and are much more resistant to leaching processes than glass matrices. It is worth noting that the best matrix materials - synrocks - were proposed by petrologists (Ringwood and others). Methods for vitrification of radioactive waste used in countries with developed nuclear energy (USA, France, Germany) do not meet the requirements for their long-term safe storage due to the specificity of glass as a metastable phase. As studies have shown, even the most resistant to physicochemical weathering processes, aluminophosphate glasses turn out to be unstable under the conditions of burial in the earth's crust. As for borosilicate glasses, according to experimental studies, under hydrothermal conditions at 350 o C and 1 kbar, they completely crystallize with the removal of radioactive waste elements into the solution. However, vitrification of radioactive waste followed by storage of glass matrices in special storage facilities is so far the only method of industrial neutralization of radionuclides.

Let us consider the properties of the available matrix materials. Table 4 presents their brief characteristics.

Table 4. Comparative characteristics matrix materials

Properties	(B,Si)-glass	(Al,P)-glass	Sinrok	NZP 1)	Clays	Zeo-lites
Ability to fix pH 2) and their breakdown products	+	+	+	+	-	+
Leach resistance	+	+	++	++	-	-
Heat resistance	+	+	++	++	-	-
Mechanical strength	+	+	++	?	-	+
Resistance to radiation damage	++	++	+	+	+	+
Stability when placed in crustal rocks	-	-	++	?	+	-
Production technology 3)	+	-	-	?	+	+
Cost of raw materials 4)	+	+	-	-	++	++

Characteristics of properties of matrix materials: “++” - very good; “+” - good; “-” - bad.

1) NZP - phases of zirconium phosphates with general formula(I A x II B y III R z IV M v V C w)(PO 4) m ; where I A x ..... V C w - elements I-V groups of the periodic table;

2) RN - radionuclides;

3) Production technology: “+” - simple; “-” - complex;

4) Feedstock: “++” - cheap; “+” - average; “-” - expensive.

From the analysis of the table it follows that there are no matrix materials that satisfy all the formulated requirements. Glasses and crystalline matrices (synroc and, possibly, nasikon) are the most acceptable in terms of their complex of physical, chemical and mechanical properties; however, the high cost of both production and starting materials, and the relative complexity of the technological scheme limit the possibilities for the widespread use of synroc for fixing radionuclides. In addition, as already mentioned, the stability of glass is insufficient for burial in the earth's crust without creating additional protective barriers.

The efforts of petrologists and experimental geochemists are focused on problems associated with the search for new modifications of crystalline matrix materials that are more suitable for the disposal of radioactive waste in rocks of the earth's crust.

First of all, solid solutions of minerals were put forward as potential matrices for fixing radioactive waste. The idea of ​​the feasibility of using solid solutions of minerals as matrices for fixing elements of radioactive waste was confirmed by the results of a wide petrological and geochemical analysis of geological objects. It is known that isomorphic substitutions in minerals are carried out mainly according to groups of elements of D.I. Mendeleev’s table:

in feldspars: Na K Rb; Ca Sr Ba; Na Ca (Sr, Ba);

in olivines: Mn Fe Co;

in phosphates: Y La...Lu, etc.

The task is to select among natural minerals with high isomorphic capacity solid solutions that are capable of

concentrate the above groups of radioactive waste elements. Table 5 shows some minerals that are potential matrices for the placement of radionuclides. Both primary and accessory minerals can be used as matrix minerals.

Table 5. Minerals - potential concentrators of radioactive waste elements.

Mineral	Mineral formula	Elements of radioactive waste isomorphically fixed in minerals
Main rock-forming minerals
Feldspar	(Na,K,Ca)(Al,Si)4O8	Ge, Rb, Sr, Ag, Cs, Ba, La...Eu, Tl
Nepheline	(Na,K)AlSiO4	Na, K, Rb, Cs, Ge
Sodalite	Na8Al6Si6O24Cl2	Na, K, Rb, Cs?, Ge, Br, I, Mo
Olivine	(Fe,Mg)2SiO4	Fe, Co, Ni, Ge
Pyroxene	(Fe,Mg)2Si2O6	Na, Al, Ti, Cr, Fe, Ni
Zeolites	(Na,Ca)[(Al,Si)nOm]k*xH2O	Co, Ni, Rb, Sr, Cs, Ba
Accessory minerals
Perovskite	(Ce,Na,Ca)2(Ti,Nb)2O6	Sr, Y, Zr, Ba, La...Dy, Th, U
Apatite	(Ca,REE)5(PO4)3(F,OH)	Y, La....Dy, I(?)
Monazite	(REE)PO4	Y, La...Dy, Th
Sphene	(Ca,REE)TiSiO5	Mn,Fe,Co?,Ni,Sr,Y,Zr,Ba,La...Dy
Zirconolite	CaZrTi2O7	Sr, Y, Zr, La...Dy, Zr, Th, U
Zircon	ZrSiO4	Y, La...Dy, Zr, Th, U

The list of minerals in Table 5 can be significantly supplemented. According to the correspondence of geochemical spectra, minerals such as apatite and sphene are most suitable for the immobilization of radionuclides, but mainly heavy rare earth elements are concentrated in zircon.

To implement the principle of “keeping like in like,” it is most convenient to use minerals. Alkaline and alkaline earth elements can be placed in minerals of the group of framework aluminosilicates, and radionuclides of the group of rare earth elements and actinides can be placed in accessory minerals.

These minerals are common in various types of igneous and metamorphic rocks. Therefore, now it is possible to solve the specific problem of choosing minerals - concentrators of elements specific to the rocks of existing landfills intended for the disposal of radioactive waste. For example, for the test sites of the Mayak plant (volcanogenic-sedimentary strata, porphyrites), feldspars, pyroxenes and accessory minerals (zircon, sphene, phosphates, etc.) can be used as matrix materials.

To create and predict the behavior of mineral matrix materials under conditions of long-term residence in rocks, it is necessary to be able to calculate reactions in the matrix - solution - host rock system, for which it is necessary to know their thermodynamic properties. In rocks, almost all minerals are solid solutions, the most common of which are framework aluminosilicates. They make up about 60% of the volume of the earth's crust and have always attracted attention and served as objects of study for geochemists and petrologists.

A reliable basis for thermodynamic models can only be the experimental study of the equilibria of minerals - solid solutions.

Assessing the resistance of matrices for radioactive waste disposal to leaching is also work that is skillfully performed by experimental petrologists and geochemists. There is a test method for the IAEA MCC-1 at 90 o C, in distilled water. The rates of leaching of mineral matrices determined from it decrease with increasing duration of experiments (in contrast to glass matrices, in which constancy of leaching rates is observed). This is explained by the fact that in minerals, after the removal of elements from the surface of the sample, the leaching rates are determined by the intracrystalline diffusion of elements, which is very low at 90 o C. Therefore, a sharp decrease in leaching rates occurs. Glass, when exposed to water, is continuously processed and crystallized, and therefore the processing zone moves deeper.

Experimental data have shown that the rates of leaching of elements from minerals vary. Leaching processes, as a rule, proceed incongruently. If we consider the extreme, most low speeds leaching (achieved in 50 - 78 days), then according to the increase in the rate of leaching of various oxides, a series is planned: Al Na (Ca) Si.

Leaching rates for individual oxides increase in the following mineral series:

for SiO 2: orthoclase scapolite nephelinelabradorite sodalite

0.0080.140 (g/m 2× day)

for Na 2 O: labradorite scapolite nepheline sodalite;

0.004 0.110 (g/m 2× day) for CaO: labradorite scapolite apatite;

0.0060.013 (g/m 2× day)

Calcium and sodium occupy the same crystal chemical positions in minerals as strontium and cesium, therefore, to a first approximation, we can assume that their leaching rates will be similar and close to those from synrock. In this regard, framework aluminosilicates are promising matrix materials for binding radionuclides, since the leaching rates of Cs and Sr from them are 2 orders of magnitude lower than for borosilicate glasses and are comparable to the leaching rates for synroc-C, which is currently the most stable matrix material.

Direct synthesis of aluminosilicates, especially from mixtures containing radioactive isotopes, requires the same complex and expensive technology as the preparation of synroc. The next step was the development and synthesis of ceramic matrices using the method of sorption of radionuclides onto zeolites with their subsequent conversion into feldspars.

It is known that some natural and synthetic zeolites have high selectivity towards Sr and Cs. However, just as easily they absorb these elements from solutions, they release them just as easily. The problem is how to retain sorbed Sr and Cs. Some of these zeolites are completely (minus water) isochemical to feldspars; moreover, the ion exchange sorption process makes it possible to obtain zeolites of a given composition, and this process is relatively easy to control and manage.

The use of phase transformations has the following advantages over other methods of radioactive waste solidification:

· the possibility of processing solutions of fragmentation radionuclides of various concentrations and ratios of elements;

· the ability to constantly monitor the process of sorption and saturation of the zeolite sorbent with radioactive waste elements in accordance with the Al / Si ratio in the zeolite;

· ion exchange on zeolites is well developed technologically and is widely used in industry for the purification of liquid waste, which implies good technological knowledge of the basics of the process;

· solid solutions of feldspars and feldspathoids obtained in the process of ceramization of zeolites are not demanding in terms of strict adherence to the Al/Si ratio in the feedstock, and the resulting matrix material corresponds to the principle of phase and chemical correspondence for mineral associations of igneous and metamorphic rocks of the earth’s crust;

· relatively simple technological scheme for the production of matrices by eliminating the calcination stage;

· ease of preparation of raw materials (natural and artificial zeolites) for use as sorbents;

· low cost of natural and synthetic zeolites, the possibility of using waste zeolites.

This method can be used to purify aqueous solutions that also contain cesium radionuclides. The transformation of zeolite into feldspathic ceramics allows, in accordance with the concept of phase and chemical correspondence, to place feldspathic ceramics in rocks in which feldspars are the main rock-forming minerals; Accordingly, leaching of strontium and cesium will be minimized. It is precisely these rocks (volcanogenic-sedimentary complex) that are located in the areas of the landfills for the proposed disposal of radioactive waste at the Mayak enterprise.

For rare earth elements, a zirconium phosphate sorbent is promising, the transformation of which produces ceramics containing zirconium phosphates of rare earths (the so-called NZP phases) - which are very stable phases to leaching and are stable in the earth's crust. The rate of leaching of rare earth elements from such ceramics is an order of magnitude lower than from synroc.

To immobilize iodine by sorption onto NaX and CuX zeolites, ceramics containing iodine-sodalite and CuI phases were obtained. The rates of iodine leaching from these ceramic materials are comparable to those of alkali and alkaline earth elements from borosilicate glass matrices.

A promising direction is the creation of two-layer matrices based on the phase correspondence of minerals of different compositions in the subsolidus region. Quartz, like feldspars, is a rock-forming mineral in many types of rocks. Special experiments have shown that the equilibrium concentration of strontium in solution (at 250 o C and pressure saturated steam) decreases by 6-10 times when quartz is added to the system. Therefore, such two-layer materials should significantly increase the resistance of matrices to leaching processes of solid solutions.

At low temperatures there is a vast area of ​​immiscibility here. This suggests the creation of a two-layer matrix with a grain of cesium calsilite in the center, covered with a layer of ordinary calsilite. Thus, the core and shell will be in equilibrium with each other, which should minimize the processes of cesium diffusion outward. Kalsilite itself is stable in alkaline igneous rocks of the potassium series, in which it will be possible to place (in accordance with the principle of phase and chemical correspondence) such “ideal” matrices. The synthesis of these matrices is also carried out by sorption followed by phase transformation. All of the above shows one example of applying the results of fundamental scientific research to solving practical problems that periodically arise before humanity.

3.1.1 Main types and physical and chemical characteristics of rocks for nuclear waste disposal.

International studies in our country and abroad have shown that three types of rocks clay (alluvium), rocks (granite, basalt, porphyrite), rock salt can serve as reservoirs for radioactive waste. All these rocks in geological formations are widespread, have sufficient area and thickness of layers or igneous bodies.

Rock salt.

Layers rock salt can serve as an object for the construction of deep disposal facilities even for highly active radioactive waste and radioactive waste with long-lived radionuclides. A feature of salt massifs is the absence of migrating waters in them (otherwise the massif could not have existed for 200-400 million years), there are almost no inclusions of liquid or gas-forming impurities, they are plastic, and structural damage in them can self-heal, they have high thermal conductivity, so they it is possible to place radioactive waste of higher activity than in other rocks. In addition, creating mine workings in rock salt is relatively easy and inexpensive. At the same time, at present, in many countries there are already tens and hundreds of kilometers of such workings. Therefore, for the disorderly storage of any waste, cavities of medium and large volume (10-300 thousand m 3) in rock salt layers, created mainly by erosion or nuclear explosions, can be used. When storing waste of low and medium activity, the temperature at the cavity wall should not exceed the geothermal temperature by more than 50°, since this will prevent evaporation of water and decomposition of minerals. On the contrary, the release of heat from high-level waste leads to the melting of salt and solidification of the melt, which fixes radionuclides. To bury all types of radioactive waste in rock salt, not very deep mines and adits can be used, while medium- and low-level waste can be poured into underground chambers in bulk or stored in barrels or cans. However, in rock salt, in the presence of moisture, the corrosion of metal containers is quite intense, which makes it difficult to use technical barriers when burying radioactive waste for a long time in salt massifs.

The advantage of salts is their high thermal conductivity, and therefore, in other cases equal conditions Temperatures in salt repositories will be lower than in storage facilities located in other environments.

The disadvantage of salts is their relatively high fluidity, which increases even more due to the heat release of HLW. Over time, underground workings are filled with salt. Therefore, waste becomes inaccessible, and its removal for processing or reburial is difficult. At the same time, the processing and practical use of HLW may in the future prove to be cost-effective. This is especially true for spent nuclear fuel containing significant amounts of uranium and plutonium.

The presence of clay layers of varying thickness in salts sharply limits the migration of radionuclides beyond natural barriers. As specially conducted studies have shown, clay minerals in these rocks form thin horizontal layers or are located in the form of small lenses and rims at the boundaries of halite grains. Brine with Cs brought into contact with the rock penetrated deep into the sample over 4 months only to the nearest clay layer. At the same time, the migration of radionuclides is hampered not only by clearly defined clay layers, but also by less contrasting deposits of clay rims around individual halite grains.

Thus, the natural composition of halite-clay has better insulating and shielding properties compared to pure halite rocks or halite with an admixture of anhydrite. Along with the property of a physical waterproofing barrier, clay minerals have high sorption properties. Consequently, in the event of depressurization of the storage facility and formation water entering it, the halite-clay formation will limit and retain the migratory forms of the main buried radionuclides. In addition, the clay remaining at the bottom of the container after erosion is an additional sorption barrier that is capable of retaining cesium and cobalt within the storage facility if they pass into the liquid phase ( emergency) .

Clays.

Clays are more suitable for constructing near-surface storage facilities or disposal sites for LLW and ILW with relatively short-lived radionuclides. However, in some countries it is planned to locate HLW in them. The advantages of clays are low water permeability and high sorption capacity for radionuclides. The disadvantage is the high cost of excavation of mine workings due to the need for their fastening, as well as reduced thermal conductivity. At temperatures above 100°C, dehydration of clay minerals begins with loss of sorbing properties and plasticity, formation of cracks and other negative consequences.

Rocky rocks.

This term covers wide range rocks consisting entirely of crystals. This includes all holocrystalline igneous rocks, crystalline schists and gneisses, as well as glassy volcanic rocks. Although salts or marbles are holocrystalline rocks, they are not included in this concept.

The advantage of crystalline rocks is their high strength and resistance to moderate temperatures, increased thermal conductivity. Mines in crystalline rocks can maintain their stability for an almost unlimited time. Groundwater in crystalline rocks usually has a low concentration of salts and a slightly alkaline reducing character, which generally meets the conditions for minimal solubility of radionuclides. When choosing a location in a crystalline massif for HLW placement, blocks with the highest strength characteristics of the constituent rocks and low fracturing are used.

Physico-chemical processes occurring in the HLW - rock - groundwater system can contribute to both increasing and decreasing the reliability of the repository. The placement of HLW in underground mine workings causes heating of the host rocks, disrupting the physicochemical equilibrium. As a result, circulation of heated solutions begins near containers with HLW, which leads to mineral formation in the surrounding space. Rocks that, as a result of interaction with heated fissure waters, will reduce their water permeability and increase sorption properties can be considered favorable.

The most favorable rocks for burial grounds are rocks in which mineral formation reactions are accompanied by clogging of cracks and pores. Thermodynamic calculations and natural observations show that the higher the basicity of the rocks, the more they meet the specified requirements. Thus, hydration of dunites is accompanied by an increase in the volume of newly formed phases by 47%, gabbro - 16, diorite - 8, granodiorite - 1%, and hydration of granites does not lead to self-healing of cracks at all. Within the temperature ranges corresponding to the conditions of the burial ground, hydration reactions will proceed with the formation of minerals such as chlorite, serpentine, talc, hydromicas, montmorillonite, and various mixed-layer phases. Characterized by high sorption properties, these minerals will prevent the spread of radionuclides outside the repository.

Thus, the insulating properties of rocks of increased basicity will increase under the influence of HLW, which allows us to consider these rocks as preferable for the construction of a repository. These include peridotites, gabbros, basalts, crystalline schists of high basicity, amphibolites, etc.

Some physical and chemical properties rocks and minerals important for radioactive waste disposal.

The study of radiation and thermal stability of rocks and minerals has shown that the interaction of radiation with rock is accompanied by a weakening of the radiation flux and the appearance of radiation defects in the structure, leading to the accumulation of energy in the irradiated material and a local increase in temperature. These processes can change the original properties of the rocks containing the waste, cause phase transitions, lead to gas formation and affect the integrity of the walls of the storage facility.

For acidic aluminosilicate rocks containing quartz and feldspars within the absorbed dose range of 10 6 -10 8 Gy, the minerals do not change their structure. For amorphization of the surface of aluminosilicates and its melting, radiation loads are required: doses of up to 10 12 Gy and simultaneous thermal exposure of 673 K. In this case, a partial loss of the density of the materials and disordering in the arrangement of aluminum in silicon-oxygen tetrahedra occurs. When clay minerals are irradiated, sorbed water appears on their surface. Therefore, for clayey rocks great value upon irradiation, it has radiolysis of water both on the outer surface and in the interlayer spaces.

However, radiation effects during the burial of even high-level waste are apparently not so important, since even γ-radiation is mainly absorbed in the radioactive waste matrix, and only a small fraction of it penetrates into the surrounding rock at a distance of about a meter. The influence of radiation is also weakened by the fact that within these same limits the greatest thermal effect occurs, causing “annealing” of radiation defects.

When using aluminosilicate rocks to accommodate waste storage, their sorption properties are positively manifested, increasing under the influence of ionizing radiation.

In Europe and Canada, when planning storage facilities, a maximum temperature of 100° C and even lower is provided; in the USA, this figure is 250° C. Some authors believe that it is inappropriate to allow the storage temperature to rise above 303 0 K, since removing the sorbed bottom can lead to a violation integrity of rocks, appearance of cracks, etc. However, others believe that in order to eliminate the surface accumulation of water films, the most rational temperature in the storage facility should be considered to be no lower than 313-323 0 K, since in this case radiation gas formation with the release of hydrogen will be optimal.

Since sorbed water is present in any geological rock, it acts as the first leaching agent. Any clay rock contains a significant amount of water (up to 12%), which under conditions elevated temperatures, characteristic of radioactive waste repositories, will be released into a separate phase and act as the first leaching agent. Thus, the creation of clay barriers in burial grounds will entail leaching processes under any type of operation, including conditionally dry ones.

The choice of place (site) for burial or storage of radioactive waste depends on a number of factors: economic, legal, socio-political and natural. A special role is given to the geological environment - the last and most important barrier to protecting the biosphere from radiation hazardous objects.

The disposal site must be surrounded by an exclusion zone in which radionuclides are allowed to appear, but outside of which activity never reaches dangerous levels. Foreign objects can be located no closer than 3 zone radii from the disposal point. On the surface this zone is called a sanitary protection zone, but underground it is an alienated block of the mountain range.

The alienated block must be removed from the sphere human activity during the decay period of all radionuclides, therefore it should be located outside mineral deposits, as well as outside the zone of active water exchange. Conducted in preparation for waste disposal engineering activities must ensure the required volume and density of radioactive waste disposal, the operation of safety and supervision systems, including long-term control over temperature, pressure and activity at the disposal site and the alienated block, as well as over the migration of radioactive substances throughout the mountain range.

From the perspective modern science, the decision on the specific properties of the geological environment at the storage site must be optimal, that is, meeting all the goals, and above all guaranteeing safety. It must be objective, that is, defendable to all interested parties. Such a decision must be understandable to the general public.

The decision must provide for the degree of risk when choosing a territory for radioactive waste disposal, as well as the risk of various emergency situations. When assessing geological sources of environmental pollution risk, it is necessary to take into account the physical (mechanical, thermal), filtration and sorption properties of rocks; tectonic situation, general seismic hazard, recent fault activity, speed of vertical movements of crustal blocks; intensity of changes in geomorphological characteristics: water abundance of the environment, activity of underground water dynamics http://zab.chita.ru/admin/pictures/426.jpgх waters, including the influence global change climate, mobility of radionuclides in groundwater; features of the degree of isolation from the surface by waterproof screens and the formation of channels for hydraulic communication of underground and surface waters; availability of valuable resources and prospects for their discovery. These geological conditions, which determine the suitability of an area for a storage facility, must be assessed independently, using a parameter representative of all risk sources. They must provide an assessment based on a set of particular criteria related to rocks, hydrogeological conditions, geological, tectonic and mineral resources. This will allow experts to give a correct assessment of the suitability of the geological environment. At the same time, the uncertainty associated with the narrowness of the information base, as well as with the subjectivity of experts, can be reduced by the use of rating scales, ranking of characteristics, a uniform form of questionnaires, and computer processing of examination results. Information about the type, quantity, short-term and long-term dynamics of spent nuclear fuel supply will provide the opportunity to perform zoning of the region's territory in order to assess the suitability of sites for storage facilities, installation (use) of communications, infrastructure development and other related, but no less important problems.

3.2 Deep geological disposal of radioactive waste.

The long time scale for which some of the waste remains radioactive has led to the idea of ​​deep geological disposal in underground repositories in stable geological formations. Isolation is provided by a combination of engineered and natural barriers (rock, salt, clay), and no obligation to actively maintain such a disposal site is passed on to future generations. This method is often referred to as a multi-barrier concept, recognizing that waste packaging, repository engineering, and the geological environment itself all provide barriers to prevent radionuclides from reaching people and the environment.

The storage facility consists of tunnels or caves dug into rocks in which packaged waste is stored. In some cases (such as wet rock), the waste containers are then surrounded by a material such as cement or clay (usually bentonite) to provide an additional barrier (called a buffer or backfill). The choice of materials for waste containers and the design and materials for the buffer varies depending on the type of waste to be contained and the nature of the rocks in which the repository is located.

Conducting tunneling and earthworks when constructing a deep underground storage facility using standard mining or civil engineering technology, is limited to accessible locations (for example, under land or under coastal zone), blocks of rock that are sufficiently stable and do not contain large flow groundwater, and depths between 250 and 1000 meters. At a depth of more than 1000 meters, excavation becomes to a greater extent technically difficult and, accordingly, more expensive.

Deep geological disposal remains the preferred option for managing long-lived radioactive waste in many countries, including Argentina, Australia, Belgium, the Czech Republic, Finland, Japan, the Netherlands, the Republic of Korea, Russia, Spain, Sweden, Switzerland and the United States. Thus, there is sufficient information available on various disposal concepts; a few examples are given here. The only purpose-built deep geological repository for long-lived intermediate level waste currently licensed for disposal operations is located in the United States. Spent fuel disposal plans are well advanced in Finland, Sweden and the United States, with the first such facility scheduled to become operational by 2010. Deep burial policies are currently being considered in Canada and the UK.

3.3 Near-surface disposal

The IAEA defines this option as the disposal of radioactive waste, with or without engineered barriers, in:

1. Near-surface burials at ground level. These burials are located at or below the surface, where the protective coating is approximately several meters thick. Waste containers are placed in constructed storage chambers, and when the chambers are full, they are filled (backfilled). Eventually they will be closed and covered with an impenetrable partition and top layer soil. These burials may include some form of drainage and possibly a gas ventilation system.

2. Near-surface burials in caves below ground level. Unlike near-surface burial at ground level, where excavation is carried out from the surface, shallow burial requires underground excavation, but the disposal is located several tens of meters below the surface of the earth and is accessible through a slightly inclined mine opening.

The term "near-surface disposal" replaces the terms "surface disposal" and "ground burial", but these older terms are still sometimes used when referring to this option.

These burial sites may be affected by long-term climate changes (eg glaciation), and this effect must be taken into account when considering safety aspects, as such changes may cause destruction of these burial sites. However, this type of disposal is usually used for low and intermediate level waste containing radionuclides with short period half-life (up to approximately 30 years).

Near-surface burials at ground level

UK – Drigg in Wales, operated by BNFL.

Spain – El Cabril, managed by ENRESA.

France – Ayube Center, managed by Andra.

Japan – Rokkase Mura, managed by JNFL.

Near-surface burials in caves below ground level currently in operation:

Sweden - Forsmark, where the burial depth is 50 meters under the bottom of the Baltic Sea.

Finland - Olkiluoto and Loviisa nuclear power plants, where the depth of each burial is about 100 meters.

3.4 Rock melting

An option for smelting rock located deep underground involves melting the waste into adjacent rock. The idea is to produce a stable, solid mass that includes the waste, or to embed the waste in a dilute form into the rock (that is, dispersed over a large volume of rock) that cannot easily be leached and transported back to the surface. This method has been proposed mainly for heat-generating wastes such as vitrified , and for breeds with suitable heat loss reduction characteristics.

Highly active waste in liquid or solid form could be placed in a cavity or deep borehole. The heat released by the waste would then be accumulated, resulting in sufficient high temperatures, in order to melt the surrounding rock and dissolve radionuclides in the growing thickness of the molten material. As the rock cools, it will crystallize and become a matrix for radioactive substances, thus dispersing the waste throughout a large volume of rock.

A variation of this option has been calculated, in which the heat generated by the waste would be accumulated in containers, and the rock would melt around the container. Alternatively, if the waste did not generate enough heat, the waste would be immobilized in the rock matrix by a conventional or nuclear explosion.

Rock melting has never been implemented to remove radioactive waste. There have been no practical demonstrations of the feasibility of this option other than laboratory studies of rock melting. Some examples of this option and its variations are described below.

In the late 1970s and early 1980s, the option of melting rock at depth was advanced to the engineering design stage. This project involved the construction of a shaft or borehole that would lead into a cavity to a depth of 2.5 kilometers. The design was reviewed but did not demonstrate that the waste would be immobile in a volume of rock one thousand times larger than the original waste volume.

Another early proposal was to design heat-resistant waste containers that would generate heat in such quantities that they would melt the underlying rock, allowing them to move down to great depths, with the molten rock solidifying above them. This alternative bore similarities to similar self-disposal methods proposed for the disposal of high-level waste in ice sheets.

In the 1990s there was renewed interest in this option, especially for the disposal of limited volumes of specialized high-level waste, especially plutonium, in Russia and the UK. A design has been proposed whereby the contents of the waste in the container, the composition of the container and its placement plan are designed to preserve the container and prevent the waste from becoming embedded in the molten rock. The host rock would only be partially melted and the container would not move to great depths.

Russian scientists have proposed that high-level waste, especially with excess plutonium, be placed in a deep shaft and immobilized by a nuclear explosion. However, the great disturbance of rock mass and groundwater caused by the use of nuclear explosions, as well as consideration of arms control measures, led to a general abandonment of this option.

3.5 Direct injection

This approach involves injecting liquid radioactive waste directly into a rock formation deep underground that is selected for its suitable waste containment characteristics (that is, minimizing any further movement after injection).

This requires a number of geological prerequisites. There must be a rock formation (the injection reservoir) with sufficient porosity to accommodate the waste and sufficient permeability to allow easy injection (i.e. act like a sponge). Above and below the injection reservoir there must be impermeable layers that could act as natural seals. Additional benefits may be provided by geological characteristics that limit horizontal or vertical movement. For example, pumping groundwater into rock layers containing natural brine. This is due to the fact that the high density of brine ( salt water) would reduce the possibility of upward movement.

Direct injection could, in principle, be used for any type of radioactive waste, provided that it is converted into a solution or slurry (very fine particles in water). Slurries containing a cement slurry that hardens underground can also be used to minimize the movement of radioactive waste. Direct injection has been implemented in Russia and the USA, as described below.

In 1957, Russia began comprehensive geological studies of formations suitable for injection of radioactive waste. Three sites were found, all in sedimentary rocks. In Krasnoyarsk-26 and Tomsk-7, injection was carried out into porous sandstone layers blocked by clays at depths of up to 400 meters. In Dimitrovgrad, injection has currently been stopped, but it was carried out there in sandstone and limestone at a depth of 1400 meters. In total, several tens of millions of cubic meters of low, medium and high activity waste were injected.

In the United States, direct injection of approximately 7,500 cubic meters of low-level waste as cement slurries was attempted in the 1970s to a depth of approximately 300 meters. It was produced over a 10-year period at Oak Ridge National Laboratory, Tennessee, and was abandoned due to uncertainty about the movement of slurry into surrounding rocks (shales). Additionally, a scheme to inject high-level waste into crystalline bedrock below the Savannah River Process Complex in South Carolina in the US was stalled before it could proceed due to public concerns.

Radioactive materials generated as waste products from the oil and gas industry are generally referred to as "Natural Advanced Technology Radioactive Materials - TENORM". In the UK, most of this waste is exempt from disposal under the UK Radioactive Substances Act 1993 due to its low level of radioactivity. However, some such wastes have higher activity. There are currently a limited number of disposal routes available, including reinjection back into the borehole (i.e. the source), which is approved by the UK Environment Agency.

3.6 Other methods of radioactive waste disposal

Disposal at sea concerns radioactive waste carried on ships and discharged into the sea in packages designed:

To explode at depth resulting in the direct release and dispersal of radioactive material into the sea, or

To dive to the seabed and reach it intact.

After some time, the physical containment of the containers will no longer be effective, and the radioactive substances will dissipate and dilute into the sea. Further dilution will cause radioactive substances to migrate away from the discharge site under the influence of currents.

The amount of radioactive substances remaining in sea ​​water, would further decrease due to natural radioactive decay and the movement of radioactive substances into seabed sediments during the sorption process.

The method of disposal of low and intermediate level waste at sea has been practiced for some time. It has gone from a generally accepted method of disposal, which was actually implemented by a number of countries, to a method that is now prohibited by international agreements. Countries that have at one time or another attempted to discharge radioactive waste into the sea using the above methods include Belgium, France, the Federal Republic of Germany, Italy, the Netherlands, Sweden and Switzerland, as well as Japan. South Korea and the USA. This option has not been implemented for high level waste.

3.6.2 Subseabed removal

The disposal option involves disposal of radioactive waste containers under the seabed into an appropriate geological environment below the ocean floor at great depth. This option has been proposed for low, medium and high level waste. Variations of this option include:

A storage facility located below the seabed. The storage facility would be accessible from land, from a small uninhabited island, or from a structure located some distance from the shore;

Disposal of radioactive waste in deep ocean sediments. This method is prohibited by international agreements.

Removal under the seabed has not been implemented anywhere and is not permitted by international agreements.

Disposal of radioactive waste in a repository created below the seabed has been considered by Sweden and the UK. If the concept of a repository below the seabed were considered desirable, the design of such a repository could be designed to ensure the possibility of future waste return. Control of waste in such a repository would be less problematic than with other forms of disposal at sea.

In the 1980s, the possibility of disposing of high level waste in deep ocean sediments was investigated and a formal report was presented by the Organization economic cooperation and development. To realize this concept, the radioactive waste was planned to be packaged in corrosion-resistant containers or glass that would be placed at least 4,000 meters below the water level in the stable deep geology of the seabed, chosen for both the slow flow of water and the ability delay the movement of radionuclides. The radioactive substances, having passed through the sediments, would then undergo the same processes of dilution, dispersion, diffusion and sorption that affect radioactive waste disposed of at sea. This disposal method therefore provides additional containment of radionuclides when compared to disposal of radioactive waste directly on the seabed.

Disposal of radioactive waste in deep ocean sediments could be accomplished by two various methods: using penetrators (devices for penetrating into sediments) or drilling wells for placement sites. The depth of disposal of waste containers below the seabed may vary for each of the two methods. If penetrators were used, waste containers could be placed in sediments to a depth of about 50 meters. The penetrators, weighing several tons, would sink into the water, receiving enough momentum to penetrate the sediment. A key aspect of radioactive waste disposal in seabed sediments is that the waste is isolated from the seabed by the thickness of the sediment. In 1986, some confidence in this method was provided by experiments undertaken at a water depth of about 250 meters in the Mediterranean Sea.

Experiments clearly showed that the entry paths created by the penetrators were closed and refilled with re-loosened sediment of approximately the same density as the surrounding undisturbed sediment.

It is also possible to place waste under the seabed using drilling equipment, which has been used at great depths for approximately 30 years. With this method, packaged waste could be placed in boreholes drilled 800 meters below the seabed, with the topmost container located about 300 meters below the seabed.

3.6.3 Removal into movement zones

Movement zones are areas in which one denser plate of the Earth's crust moves lower towards another, lighter plate. The thrust of one lithospheric plate onto another leads to the formation of a fault (trench) that appears at some distance from the sea coast, and causes earthquakes that occur in the zone of inclined contact of the earth's crust plates. The edge of the dominant plate crushes and rises, forming a chain of mountains parallel to the fault. Deep marine sediments are scraped off the downgoing plate and built into adjacent mountains. When an ocean plate sinks into the hot mantle, parts of it can begin to melt. This is how magma is formed, migrating upward, part of it reaches the surface of the earth in the form of lava erupting from volcanic craters. As shown in the accompanying illustration, the idea for this option was to bury the waste in such a fault zone that it would then be carried deeper into the earth's crust.

This method is not permitted by international agreements because it is a form of disposal at sea. Although zones of plate movement exist in a number of places on the Earth's surface, their number is very limited geographically. No country producing radioactive waste has the right to consider disposal in deep sea trenches without finding an internationally acceptable solution to this problem. However, this option has not been implemented anywhere, since it is one of the forms of radioactive waste disposal at sea and therefore is not permitted by international agreements.

3.6.4 Burial in ice sheets

In this disposal option, containers containing heat-emitting waste would be placed in stable ice sheets, such as those found in Greenland and Antarctica. The containers would melt the surrounding ice and sink deep into the ice sheet, where the ice could recrystallize above the waste, creating a powerful barrier.

Although disposal into ice sheets could technically be considered for all types of radioactive waste, it has only been seriously explored for high level waste where the heat generated by the waste could be advantageously used to self-bury the waste within the ice by melting it.

The option of removal in ice sheets has never been implemented. It has been rejected by countries that have signed the Antarctic Treaty or are committed to providing a solution for managing their radioactive waste within their national borders. Since 1980, no serious examination of this option has been carried out.

3.6.5 Removal into outer space

This option aims to remove radioactive waste from Earth forever by releasing it into space. Obviously, the waste must be packaged in such a way as to remain undamaged in the most unimaginable accident scenarios. A rocket or space shuttle could be used to launch packaged waste into outer space. Several final destinations for the waste were considered, including directing it towards the Sun, keeping it in orbit around the Sun between Earth and Venus, and throwing the waste away altogether. solar system. This is necessary because the placement of waste in outer space in low-Earth orbit is fraught with its possible return to Earth.

The high cost of this option means that this method of radioactive waste disposal might be suitable for high level waste or spent fuel (that is, long-lived, highly radioactive material that is relatively small in volume). Recycling of the waste might be required to separate the more radioactive materials for disposal into outer space and therefore reduce the volume of cargo transported. This option was not pursued and further research was not carried out due to the high cost and due to the safety aspects involved With possible risk unsuccessful launch.

The most detailed studies of this option were carried out in the United States by NASA in the late 1970s and early 1980s. Currently NASA. Only thermal radioisotope generators (TRGs) containing several kilograms of Pu-238 are launched into space.

4. Radioactive waste and spent nuclear fuel in the Russian nuclear power industry.

What is the real situation with radioactive waste from nuclear power plants in Russia? Nuclear power plants are storage sites for radioactive waste generated in addition to spent fuel. About 300 thousand m3 of radioactive waste with a total activity of about 50 thousand curies are stored on the territory of Russian nuclear power plants. Not a single nuclear power plant has a complete set of installations for conditioning radioactive waste. Liquid radioactive waste is evaporated, and the resulting concentrate is stored in metal containers, in some cases pre-cured by bituminization. Solid radioactive waste is placed in special storage facilities without prior preparation. Only three nuclear power plants have pressing plants and two stations have solid radioactive waste combustion plants. These technical means are clearly not enough from the standpoint modern approach to ensure radiation and environmental safety. Very serious difficulties arose due to the fact that solid and solidified waste storage facilities in many Russian nuclear power plants crowded. Most nuclear power plants do not have a complete set of technical equipment necessary from the standpoint of a modern approach to ensuring radiation and environmental safety. Nuclear energy cannot exist otherwise than by producing more and more quantities of artificial radionuclides, including plutonium, which until the early 40s of the last century nature did not know and to which it is not adapted. To date, as a result of the operation of nuclear power plants with reactor VVER and RBMK plants store about 14 thousand tons of spent nuclear fuel in storage facilities of various types and accessories, its total radioactivity is 5 billion Ci (34.5 Ci for each person). Most of it (about 80%) is stored in reactor storage pools and station spent fuel storage facilities, the rest of the fuel is in centralized storage facilities of the RT-1 plant at the Mayak Production Association and at the Mining and Chemical Combine (MCC) near Krasnoyarsk (VVER-SNF 1000). The annual increase in spent fuel is about 800 tons (135 tons of spent fuel are supplied annually from VVER-1000 reactors).

The specificity of spent fuel from Russian nuclear power plants is its diversity both in physical and technical parameters and in the weight and size characteristics of fuel assemblies, which determines differences in the approach to further handling of spent fuel. An unresolved element in this scheme is the creation of production of mixed uranium-plutonium fuel from regenerated plutonium accumulated at the RT-1 plant of the Mayak Production Association in a volume of -30 tons.

For reactors of the VVER-1000 and RBMK-1000 types, a forced solution (for a number of reasons) is the intermediate long-term storage of spent fuel from this waste before the start of reprocessing, which is not included in the cost of the final product - electricity.

5. Problems of the radioactive waste management system in Russia and possible ways to solve them

5.1 Structure of the radioactive waste management system in the Russian Federation

The problem of radioactive waste management is multifaceted and complex, and is complex in nature. When deciding it, it is necessary to take into account various factors, including a possible increase in the cost of products or services of enterprises due to the imposition of new requirements for the storage and management of radioactive waste, the use of special mandatory technologies for radioactive waste management, the variety of methods for managing radioactive waste depending on their specific activity, physico-chemical state, radionuclide composition, volumes, toxicity, and conditions for safe storage and disposal. Analysis of the regulatory framework of the Russian Federation regulating the management of radioactive waste at the final stage of the nuclear fuel cycle - the structure of the regulatory framework technical documentation, compliance with requirements for various stages of radioactive waste management in documents of various levels, etc. showed that it lacks documents defining:

the fundamentals of state policy in the field of radioactive waste management, which would define property rights in the field of radioactive waste management and sources of financing for this activity, as well as the responsibility of enterprises producing radioactive waste;

maximum volumes and terms of temporary storage of various radioactive waste;

the procedure for agreeing and making decisions on the location of final isolation (disposal) points for radioactive waste;

methods for assessing the safety of final isolation facilities and methods for obtaining initial data for such assessments, as well as a number of other important points.

In addition, the current documents contain contradictions and also require improvement. Thus, the existing classification of radioactive waste (by activity level) does not contain instructions on the required periods of waste isolation from the biosphere and, as a consequence, methods of their disposal.

The current situation with radioactive waste is characterized by the following figures. According to the state accounting and control system for radioactive substances and radioactive waste, as of January 1, 2004, more than 1.5 billion Ci (5.96E+19Bq) have been accumulated in the Russian Federation, of which more than 99% is concentrated at Rosatom enterprises.

Most waste is located in temporary storage facilities. One of important reasons accumulation of large volumes of radioactive waste in storage facilities is the current ineffective approach to waste management. It is currently accepted that all generated waste should be stored for 30-50 years with the possibility of extending the storage period. This path does not lead to a final safe solution to the problem and requires significant costs for the operation of storage facilities without a clear prospect of eliminating the latter. At the same time final decision the problem of accumulation of radioactive waste is transferred to subsequent generations.

An alternative is to introduce the principle of final isolation of radioactive waste, in which the risks of accidents and the negative impact of radioactive waste on humans and the environment are reduced by approximately 2-3 orders of magnitude. Consequently, the main method of isolation should not be long-term storage, but the final disposal of waste. Considering climatic conditions In Russia, underground waste isolation is safer than near-surface isolation.

The current situation is complicated by the “bulk” placement of solid radioactive waste, which has been used until recently at the storage facilities of enterprises that are sources of radioactive waste, as a rule.

RW storage facilities were created taking into account the specifics of the enterprises and the technologies used, as a result of which there are practically no standard solutions for waste isolation. Solid radioactive waste is stored in storage facilities of more than 30 various types, represented mainly by specialized buildings or internal industrial premises, trenches and bunkers, tanks and open areas. Liquid waste is stored in more than 18 different types of storage facilities, mainly represented by free-standing containers, open reservoirs, slurry storage facilities, etc. The storage facility designs did not provide for solutions for their decommissioning and subsequent rehabilitation of the territories. All this significantly complicates the determination of radionuclide and chemical composition stored waste and makes it difficult or often impossible to remove it.

There are no standard solutions in the industry for processing and preparing radioactive waste for disposal. Technologies for processing and conditioning of radioactive waste, and, accordingly, processing plants, were created taking into account the specifics of the radioactive waste generated at each enterprise and, for the most part, are not unified and universal.

The complex of problems described in the field of radioactive waste management determines the need to modernize the current system.

5.2 Proposals for changing the doctrine of radioactive waste management

Fundamentals of technical policy for effective solution The problems of final isolation of existing radioactive waste in the Russian Federation can be formulated as follows:

Changing the existing conceptual approach to waste isolation. In RW management projects, the main method of waste isolation should not be long-term storage, but the final disposal of waste without possible recovery;

Minimizing the creation of new surface and near-surface radioactive waste storage facilities at enterprises;

Use of territories adjacent to enterprises that are sources of generation and accumulation of large volumes of waste and have experience and licenses for handling them to create new regional and local radioactive waste repositories, if possible, with maximum use of existing underground facilities being decommissioned;

Use of standard radioactive waste management technologies for certain types of waste and types of storage facilities;

Development or modification of legislative and regulatory technical documentation for the implementation of disposal of all types of radioactive waste.

6. Conclusion

Thus, we can conclude that the most realistic and promising way to dispose of radioactive waste is their geological disposal. The difficult economic situation in our country does not allow the use of alternative, expensive disposal methods on an industrial scale.

Therefore, the most important task of geological research will be to study the optimal geological conditions for the safe disposal of radioactive waste, possibly on the territory of specific nuclear industry enterprises. The fastest way to solve the problem is to use borehole repositories, the construction of which does not require large capital costs and allows you to begin HLW burial in relatively small-sized geological blocks of favorable rocks.

It seems relevant to create scientific and methodological guidelines for choosing the geological environment for HLW disposal and identifying the most promising places in Russia for the construction of repositories.

A very promising area of ​​geological and mineralogical research by Russian scientists may be the study of the insulating properties of the geological environment and the sorption properties of natural mineral mixtures.

7. List of used literature:

1. Belyaev A.M. Radioecology

2. Based on materials from the conference “Safety of Nuclear Technologies: Economics of Safety and Handling of IRS”

3. Kedrovsky O.L., Shishits Yu.I., Leonov E.A., et al. Main directions for solving the problem of reliable isolation of radioactive waste in the USSR. // Atomic energy, vol. 64, issue 4. 1988, p. 287-294.

4. IAEA Bulletin. T. 42. No. 3. - Vienna, 2000.

5. Kochkin B.T. Selection of geological conditions for the disposal of highly radioactive waste // Dis. for the job application d. g.-m. n. IGEM RAS, M., 2002.

6. Laverov N.P., Omelyanenko B.I., Velichkin V.I. Geological aspects of the problem of radioactive waste disposal // Geoecology. 1999. No. 6.

The existence of living organisms (people, birds, animals, plants) on earth largely depends on how protected the environment in which they live is from pollution. Every year, humanity accumulates a huge amount of garbage, and this leads to the fact that radioactive waste becomes a threat to the whole world if it is not destroyed.

Now there are already many countries where the problem of environmental pollution, the sources of which are household, industrial waste, pay special attention to:

• separate household waste and then use methods to safely recycle it;
• build waste recycling plants;
• create specially equipped sites for the disposal of hazardous substances;
• create new technologies for processing secondary raw materials.

Countries such as Japan, Sweden, Holland and some other states on the issues of radioactive waste disposal and disposal household waste are taken seriously.

The result of an irresponsible attitude is the formation of giant landfills, where waste products decompose, turning into mountains of toxic waste.

When did the waste appear?

With the advent of man on Earth, waste also appeared. But if the ancient inhabitants did not know what light bulbs, glass, polyethylene and others were modern achievements, then now scientific laboratories are working on the problem of destroying chemical waste, where talented scientists are attracted. It is still not entirely clear what awaits the world in hundreds, thousands of years if waste continues to accumulate.

The first household inventions appeared with the development of glass production. At first, little was produced, and no one thought about the problem of waste generation. Industry, keeping pace with scientific achievements, began to actively develop by the beginning of the 19th century. Factories that used machinery grew rapidly. Tons of processed coal were released into the atmosphere, which polluted the atmosphere due to the formation of acrid smoke. Now industrial giants are “feeding” rivers, seas and lakes with huge amounts of toxic emissions, natural springs inevitably become places of their burial.

Classification

In Russia, Federal Law No. 190 of July 11, 2011 is in force, which reflects the main provisions for the collection and management of radioactive waste. The main evaluation criteria by which radioactive waste is classified are:

• disposed - radioactive waste that does not exceed the risks of radiation exposure and the costs of removal from storage with subsequent burial or management.
• special - radioactive waste that exceeds the risks of radiation exposure and the costs of subsequent disposal or recovery.

Radiation sources are dangerous due to their detrimental effect on the human body, and therefore the need to localize active waste is extremely important. Nuclear power plants produce almost nothing, but there is another difficult problem associated with them. Spent fuel is filled into containers; they remain radioactive for a long time, and its quantity is constantly growing. Back in the 50s, the first research attempts were made to solve the problem of radioactive waste. Proposals have been made to send them into space, store them on the ocean floor and other hard-to-reach places.

There are different landfill plans, but decisions on how to use the sites are contested public organizations and environmentalists. State scientific laboratories have been working on the problem of destroying the most hazardous waste almost since nuclear physics appeared.

If successful, this will reduce the amount of radioactive waste generated by nuclear power plants by up to 90 percent.

What happens in nuclear power plants is that a fuel rod containing uranium oxide is contained in a stainless steel cylinder. It is placed in a reactor, the uranium decays and releases thermal energy, it drives a turbine and produces electricity. But after only 5 percent of the uranium was exposed radioactive decay, the entire rod becomes contaminated with other elements and must be disposed of.

This produces so-called spent radioactive fuel. It is no longer useful for generating electricity and becomes waste. The substance contains impurities of plutonium, americium, cerium and other by-products of nuclear decay - this is a dangerous radioactive “cocktail”. American scientists are conducting experiments using special devices to artificially complete the nuclear decay cycle.

Waste disposal

The facilities where radioactive waste is stored are not marked on maps, there are no identification signs on the roads, and the perimeter is carefully guarded. At the same time, it is prohibited to show the security system to anyone. Several dozen such objects are scattered across Russia. Radioactive waste storage facilities are being built here. One of these associations reprocesses nuclear fuel. Nutrients separated from active waste. They are disposed of, and valuable components are again sold.

The requirements of the foreign buyer are simple: he takes the fuel, uses it, and returns the radioactive waste. They are taken to the factory by railway, loading is done by robots, and it is mortally dangerous for a person to approach these containers. Sealed, durable containers are installed in special cars. A large carriage is turned over, containers with fuel are placed using special machines, then it is returned to the rails and special compounds with the warning railway services and the Ministry of Internal Affairs, they are sent from the nuclear power plant to the enterprise point.

In 2002, “green” demonstrations took place, they protested against the import of nuclear waste into the country. Russian nuclear scientists believe that they are being provoked by foreign competitors.

Specialized factories process waste of medium and low activity. Sources - everything that surrounds people in everyday life: irradiated parts of medical devices, parts electronic technology and other devices. They are brought in containers on special vehicles that deliver radioactive waste via regular roads, accompanied by police. Externally, they are distinguished from a standard garbage truck only by their coloring. At the entrance there is a sanitary checkpoint. Here everyone must change clothes and change shoes.

Only after this can you get to workplace, where it is prohibited to eat, drink alcohol, smoke, use cosmetics or be without overalls.

For employees of such specific enterprises, this is normal work. The difference is one thing: if a red light suddenly lights up on the control panel, you need to immediately run away: the radiation sources can neither be seen nor felt. Control devices are installed in all rooms. When everything is in order, the green lamp is on. The workspaces are divided into 3 classes.

1st class

Waste is processed here. In the furnace, radioactive waste is turned into glass. People are prohibited from entering such premises - it is mortally dangerous. All processes are automated. You can only enter in the event of an accident while wearing special protective equipment:

• insulating gas mask (special protection made of lead, absorbing, shields for eye protection);
• special uniforms;
• remote means: probes, grippers, special manipulators;

By working in such enterprises and following impeccable safety precautions, people are not exposed to radiation.

2nd grade

From here the operator controls the furnaces; on the monitor he sees everything that happens in them. The second class also includes rooms where they work with containers. They contain waste of different activity. There are three basic rules here: “stand further”, “work faster”, “don’t forget about protection”!

You cannot pick up a waste container with your bare hands. There is a risk of serious radiation exposure. Respirators and work gloves are worn only once; when they are removed, they also become radioactive waste. They are burned and the ashes are decontaminated. Each worker always wears an individual dosimeter, which shows how much radiation is collected during the work shift and the total dose; if it exceeds the norm, the person is transferred to safe work.

3rd grade

This includes corridors and ventilation shafts. There is a powerful air conditioning system here. Every 5 minutes the air is completely replaced. The radioactive waste processing plant is cleaner than the kitchen of a good housewife. After each transportation, the vehicles are watered with a special solution. Several people work in rubber boots with a hose in their hands, but the processes are being automated so that they become less labor-intensive.

The workshop area is washed with water and ordinary washing powder 2 times a day, the floor is covered with plastic compound, the corners are rounded, the seams are well taped, there are no baseboards or hard-to-reach places that cannot be thoroughly washed. After cleaning, the water becomes radioactive, it flows into special holes and is collected through pipes into a huge container underground. Liquid waste is carefully filtered. The water is purified so that it can be drunk.

Radioactive waste is hidden “under seven locks.” The depth of the bunkers is usually 7-8 meters, the walls are reinforced concrete, while the storage facility is being filled, a metal hangar is installed above it. Containers with a high degree of protection are used to store very hazardous waste. Inside such a container is lead, there are only 12 small holes the size of a gun cartridge. Less hazardous waste is placed in huge reinforced concrete containers. All this is lowered into the shafts and closed with a hatch.

These containers can later be removed and sent for subsequent processing to complete the final disposal of radioactive waste.

Filled storage facilities are filled with a special type of clay; in the event of an earthquake, it will glue the cracks together. The storage facility is covered with reinforced concrete slabs, cemented, asphalted and covered with earth. After this, radioactive waste poses no danger. Some of them decay into safe elements only after 100–200 years. On secret maps where vaults are marked, there is a stamp “keep forever”!

Landfills where radioactive waste is buried are located at a considerable distance from cities, towns and reservoirs. Nuclear energy, military programs - problems that concern everyone world community. They are not only to protect people from the influence of sources of radioactive waste, but also to carefully protect them from terrorists. It is possible that landfills where radioactive waste is stored could become targets during military conflicts.

Radioactive waste has become an extremely pressing problem of our time. If at the dawn of energy development few people thought about the need to store waste material, now this task has become extremely urgent. So why is everyone so worried?

Radioactivity

This phenomenon was discovered in connection with the study of the relationship between luminescence and x-rays. IN late XIX century, during a series of experiments with uranium compounds, the French physicist A. Becquerel discovered a previously unknown substance passing through opaque objects. He shared his discovery with the Curies, who began to study it closely. It was the world-famous Marie and Pierre who discovered that all uranium compounds have this property, as does it itself in its pure form, as well as thorium, polonium and radium. Their contribution was truly invaluable.

Later it became known that all chemical elements, starting with bismuth, are radioactive in one form or another. Scientists also thought about how the process of nuclear decay could be used to produce energy, and were able to initiate and reproduce it artificially. And to measure the level of radiation, a radiation dosimeter was invented.

Application

In addition to energy, radioactivity has received wide application and in other sectors: medicine, industry, scientific research And agriculture. Using this property, they have learned to stop the spread of cancer cells, make more accurate diagnoses, find out the age of archaeological values, and monitor the transformation of substances into various processes etc. List possible applications radioactivity is constantly expanding, so it is even surprising that the issue of disposal of waste materials has become so acute only in recent decades. But this is not just garbage that can be easily thrown into a landfill.

Radioactive waste

All materials have their own service life. This is no exception for elements used in nuclear energy. The output is waste that still has radiation, but no longer has any practical value. As a rule, used materials that can be recycled or used in other areas are considered separately. In this case we're talking about just about radioactive waste (RAW), the further use of which is not envisaged, so it is necessary to get rid of it.

Sources and forms

Due to the variety of uses, waste can also have different origins and condition. They can be either solid, liquid or gaseous. The sources can also be very different, since in one form or another such waste often arises during the extraction and processing of minerals, including oil and gas, and there are also categories such as medical and industrial radioactive waste. There are also natural sources. Conventionally, all this radioactive waste is divided into low-, medium- and high-level. In the USA there is also a category of transuranium radioactive waste.

Options

Enough for a long time It was believed that the disposal of radioactive waste did not require special rules; it was enough just to disperse it into the environment. However, it was later discovered that isotopes tend to accumulate in certain systems, such as animal tissues. This discovery changed the opinion about radioactive waste, since in this case the probability of their movement and entry into the human body with food became quite high. Therefore, it was decided to develop some options for how to deal with this type of waste, especially for the high-level category.

Modern technologies make it possible to maximally neutralize the danger posed by radioactive waste by processing them in various ways or placement in a safe space for humans.

1. Vitrification. This technology is otherwise called vitrification. In this case, radioactive waste goes through several stages of processing, as a result of which a fairly inert mass is obtained, which is placed in special containers. These containers are then sent to storage.
2. Sinrok. This is another method of radioactive waste neutralization developed in Australia. In this case, the reaction uses a special complex compound.
3. Burial. At this stage, a search is underway for suitable places in the earth's crust where radioactive waste could be placed. The most promising project seems to be one in which waste material is returned to
4. Transmutation. Reactors capable of converting highly active radioactive waste into less hazardous substances are already being developed. At the same time as waste neutralization, they are capable of generating energy, so technologies in this area are considered extremely promising.
5. Removal into outer space. Although this idea is attractive, it has many disadvantages. Firstly, this method is quite expensive. Secondly, there is a risk of a launch vehicle accident, which could be catastrophic. Finally, the contamination of outer space with such waste can lead to big problems after some time.

Disposal and storage rules

In Russia, radioactive waste management is regulated primarily federal law and comments thereto, as well as some related documents, for example, Water Code. According to the Federal Law, all radioactive waste must be buried in the most isolated places, while contamination is not allowed water bodies, sending into space is also prohibited.

Each category has its own regulations, in addition, the criteria for classifying waste as a particular type and all the necessary procedures are clearly defined. However, Russia has a lot of problems in this area. Firstly, the disposal of radioactive waste may very soon become a non-trivial task, because there are not many specially equipped storage facilities in the country, and quite soon they will be filled. Secondly, there is no unified system for managing the recycling process, which seriously complicates control.

International projects

Taking into account the fact that the storage of radioactive waste has become most relevant after the termination, many countries prefer to cooperate on this issue. Unfortunately, it has not yet been possible to reach a consensus in this area, but discussions of various programs at the UN continue. The most promising projects seem to be to build a large international storage facility for radioactive waste in sparsely populated areas, as a rule, we are talking about Russia or Australia. However, citizens of the latter are actively protesting against this initiative.

Consequences of radiation

Almost immediately after the discovery of the phenomenon of radioactivity, it became clear that it negatively affects the health and life of humans and other living organisms. The research that the Curies carried out over several decades ultimately led to a severe form of radiation sickness in Maria, although she lived to be 66 years old.

This disease is the main consequence of human exposure to radiation. The manifestation of this disease and its severity mainly depend on the total radiation dose received. They can be quite mild or cause genetic changes and mutations, thus affecting subsequent generations. One of the first to suffer is the hematopoietic function; patients often experience some form of cancer. However, in most cases, treatment turns out to be quite ineffective and consists only of observing an aseptic regimen and eliminating symptoms.

Prevention

Preventing conditions associated with exposure to radiation is quite simple - just stay out of areas with high levels of radiation. Unfortunately, this is not always possible, because many modern technologies involve active elements in one form or another. In addition, not everyone carries a portable radiation dosimeter with them to know that they are in an area where prolonged exposure can cause harm. However, there are certain measures to prevent and protect against dangerous radiation, although there are not many of them.

Firstly, this is shielding. Almost everyone who came for an x-ray of a certain part of the body encountered this. If we are talking about the cervical spine or skull, the doctor suggests wearing a special apron with lead elements sewn into it that does not allow radiation to pass through. Secondly, you can maintain the body's resistance by taking vitamins C, B 6 and P. Finally, there are special drugs - radioprotectors. In many cases they turn out to be very effective.

2. Radioactive waste. Origin and classification. 4

2.1 Origin of radioactive waste. 4

2.2 Classification of radioactive waste. 5

3. Disposal of radioactive waste. 7

3.1. Disposal of radioactive waste in rocks. 8

3.1.1 Main types and physical and chemical characteristics of rocks for nuclear waste disposal. 15

3.1.2 Selecting a radioactive waste disposal site. 18

3.2 Deep geological disposal of radioactive waste. 19

3.3 Near-surface disposal. 20

3.4 Rock melting21

3.5Direct injection22

3.6 Other methods of disposal of radioactive waste23

3.6.1 Removal at sea23

3.6.2 Removal under the seabed... 23

3.6.3 Removal into movement zones. 24

3.6.4 Burial in ice sheets.. 25

3.6.5 Removal into outer space.. 25

4. Radioactive waste and spent nuclear fuel in the Russian nuclear power industry. 25

5. Problems of the radioactive waste management system in Russia and possible ways to solve it... 26

5.1 Structure of the radioactive waste management system in the Russian Federation.. 26

5.2 Proposals for changing the doctrine of radioactive waste management.. 28

6. Conclusion.. 29

7. List of used literature: 30

1. Introduction

The second half of the twentieth century was marked by a sharp aggravation of environmental problems. The scale of mankind's technogenic activity is currently comparable to geological processes. To the previous types of environmental pollution, which have received extensive development, a new danger of radioactive contamination has been added. The radiation situation on Earth has undergone significant changes over the past 60-70 years: by the beginning of World War II, all countries of the world had about 10-12 g of natural radioactive substance radium obtained in its pure form. Nowadays, one medium-power nuclear reactor produces 10 tons of artificial radioactive substances, most of which, however, are short-lived isotopes. Radioactive substances and sources of ionizing radiation are used in almost all industries, in healthcare, and in conducting a wide variety of scientific research.

Over the past half century, tens of billions of curies of radioactive waste have been generated on Earth, and these numbers are increasing every year. The problem of recycling and disposal of radioactive waste from nuclear power plants is becoming especially acute now, when the time has come to dismantle the majority of nuclear power plants in the world (according to the IAEA, these are more than 65 nuclear power plant reactors and 260 reactors used for scientific purposes). There is no doubt that the most significant volume of radioactive waste was generated on the territory of our country as a result of the implementation of military programs for more than 50 years. During the creation and improvement of nuclear weapons, one of the main tasks was the rapid production of nuclear fissile materials that give a chain reaction. Such materials are highly enriched uranium and weapons-grade plutonium. The largest above-ground and underground storage facilities for radioactive waste have formed on Earth, posing a huge potential danger to the biosphere for many hundreds of years.

http://zab.chita.ru/admin/pictures/424.jpgThe issue of radioactive waste management involves an assessment of different categories and storage methods, as well as different requirements for environmental protection. The purpose of disposal is to isolate waste from the biosphere for extremely long periods of time, to ensure that residual radioactive substances reaching the biosphere will be in negligible concentrations compared to, for example, natural background radioactivity, and to ensure that the risk from careless intervention the person will be very small. Geological disposal has been widely proposed to achieve these goals.

However, there are many different proposals regarding methods for disposing of radioactive waste, for example:

· Long-term above-ground storage,

· Deep wells (at a depth of several km),

Rock melting (suggested for heat-generating waste)

· Direct injection (suitable for liquid waste only),

· Removal at sea,

· Removal to the ocean floor,

· Removal into movement zones,

· Removal into ice sheets,

· Removal into space

Some proposals are still being developed by scientists from around the world, others have already been prohibited by international agreements. Most scientists studying this problem recognize the most rational option for burying radioactive waste in the geological environment.

The problem of radioactive waste is an integral part of “Agenda 21”, adopted at the World Summit on Earth in Rio de Janeiro (1992) and the “Program of Action for the Further Implementation of Agenda 21”, adopted Special session of the United Nations General Assembly (June 1997). The latest document, in particular, outlines a system of measures to improve methods of managing radioactive waste, to expand international cooperation in this area (exchange of information and experience, assistance and transfer of relevant technologies, etc.), to tighten the responsibility of states for ensuring safe storage and removal of radioactive waste.

In my work I will try to analyze and evaluate the disposal of radioactive waste in the geological environment, as well as the possible consequences of such disposal.

2. Radioactive waste. Origin and classification.

2.1 Origin of radioactive waste.

Radioactive waste includes materials, solutions, gaseous media, products, equipment, biological objects, soil, etc. that are not subject to further use, in which the content of radionuclides exceeds the levels established by regulations. Spent nuclear fuel (SNF) may also be included in the “RAW” category if it is not subject to subsequent processing in order to extract components from it and, after appropriate storage, is sent for disposal. RW is divided into high-level waste (HLW), intermediate-level waste (ILW) and low-level waste (LLW). The division of waste into categories is established by regulations.

Radioactive waste is a mixture of stable chemical elements and radioactive fragmentation and transuranium radionuclides. Fragmentation elements numbered 35-47; 55-65 are fission products of nuclear fuel. During 1 year of operation of a large power reactor (when loading 100 tons of nuclear fuel with 5% uranium-235), 10% (0.5 tons) of fissile material is produced and approximately 0.5 tons of fragmentation elements are produced. Nationwide, 100 tons of fragmentation elements are produced annually at nuclear power reactors alone.

Main and the most dangerous for the biosphere, the elements of radioactive waste are Rb, Sr, Y, Zr, Mo, Ru, Rh, Pd, I, Cs, Ba, La....Dy and transuranic elements: Np, Pu, Am and Cm. Solutions of radioactive waste with high specific activity in composition are mixtures of nitric acid salts with a nitric acid concentration of up to 2.8 mol/liter, they contain additives HF(up to 0.06 mol/liter) and H2SO4(up to 0.1 mol/liter). The total content of salts of structural elements and radionuclides in solutions is approximately 10 wt%. Transuranium elements are formed as a result of the neutron capture reaction. In nuclear reactors, fuel (enriched natural uranium) is in the form of tablets UO 2 placed in tubes made of zirconium steel (fuel element - TVEL). These tubes are located in the reactor core; between them are placed moderator blocks (graphite), control rods (cadmium) and cooling tubes through which the coolant circulates - most often, water. One load of fuel rods lasts approximately 1-2 years.

Radioactive waste is generated:

During the operation and decommissioning of nuclear fuel cycle enterprises (mining and processing of radioactive ores, manufacturing of fuel elements, electricity generation at nuclear power plants, reprocessing of spent nuclear fuel);

In the process of implementing military programs for the creation of nuclear weapons, conservation and liquidation of defense facilities and rehabilitation of territories contaminated as a result of the activities of enterprises producing nuclear materials;

During the operation and decommissioning of ships of the naval and civil fleets with nuclear power plants and their maintenance bases;

When using isotope products in the national economy and medical institutions;

As a result of nuclear explosions in the interests of the national economy, during the extraction of mineral resources, during the implementation of space programs, as well as during accidents at nuclear facilities.

When radioactive materials are used in medical and other research institutions, a significantly smaller amount of radioactive waste is generated than in the nuclear industry and the military-industrial complex - this is several tens of cubic meters of waste per year. However, the use of radioactive materials is expanding, and with it the volume of waste is increasing.

2.2 Classification of radioactive waste

RW is classified according to various criteria (Fig. 1): by state of aggregation, by composition (type) of radiation, by lifetime (half-life) T 1/2), by specific activity (radiation intensity). However, the classification of radioactive waste used in Russia by specific (volume) activity has its disadvantages and positive aspects. The disadvantages include the fact that it does not take into account the half-life, radionuclide and physico-chemical composition of the waste, as well as the presence of plutonium and transuranium elements in them, the storage of which requires special stringent measures. The positive side is that at all stages of radioactive waste management, including storage and disposal, the main task is to prevent environmental pollution and overexposure of the population, and the separation of radioactive waste depending on the level of specific (volume) activity is precisely determined by the degree of their impact on the environment and humans . The measure of radiation hazard is influenced by the type and energy of radiation (alpha, beta, gamma emitters), as well as the presence of chemically toxic compounds in waste. The duration of isolation from the environment for intermediate-level waste is 100-300 years, for high-level waste - 1000 years or more, for plutonium - tens of thousands of years. It is important to note that radioactive waste is divided depending on the half-life of radioactive elements: short-lived, with a half-life of less than a year; medium-lived from a year to a hundred years and long-lived more than a hundred years.

Apartments in new buildings in Japan are rated not by the level of comfort or prestige of the area, but by the level of radiation in the apartments. This explains why life expectancy in Japan is 87 years, and in Russia it is 70.

There are no radiation certificates in new buildings in Moscow, so some apartments simply “glow” from radiation. According to experts, after research, such apartments will fall in price tens of times. The price for this is at least 10 years of human life.

Radiation occurs in Moscow

• 45-55% - natural background radiation of the earth and radiation from the sun
• 20-35% - medical examinations
• from 2% to 20% - radioactive gas Radon, which is contained in the ground, in the basements of residential buildings rises into apartments through ventilation shafts
• from 0.1% to 15% - nuclear rectors, of which there are 11 in Moscow, and enterprises working with radioactive materials - there are more than 2,500 of them in Moscow
• 1% - food
• from 5 to 50% - wall material in apartments of houses - radioactive sand, clay, gravel, granite, etc.

Moreover, some construction companies are building new buildings on contaminated sites. Moscow developers, without having maps of radioactive contamination in Moscow, can build new buildings in dangerous areas, as happened in the area of ​​Rokosovsky Boulevard, the so-called “Green Hill” - a nuclear waste burial site:

Dangerous enterprises in Moscow:

• ITEP (Institute of Theoretical and experimental physics)
• Kurchatov Institute (Institute of Atomic Energy)
• Bochvar Institute of Inorganic Materials
• NIKIET
• Mosrentgen village
• Polymetals Plant
• NIIHT
• Plant "Molniya"
• Low-background underground laboratory - at a depth of 27 meters under the Ukraine Hotel
• Marshal Rokossovsky Boulevard ("Green Hill")
• At Poklonnaya Gora (from the side of the railway embankment next to the museum of military equipment).

There are entire nuclear agglomerations consisting of nuclear institutes, nuclear plants and radioactive dumps:

In addition, there are five more reactors in Khimki and Lytkarino. Total area the capital is more than one thousand one hundred square kilometers. (Without New Moscow). At the same time, only official dangerous radiation objects are 18 units. There is no such density in any capital in the world. But the main thing is not quantity, but quality.

In Moscow, infection sites are located directly next to residential areas. About this in this material.

Main in this issue is that this topic completely closed. Neither Rosatom nor the Ministry of Defense, citing state secrets, want to share data on the condition of facilities or emergency incidents. A special problem is “ringing” apartments in new buildings in Moscow.

Construction companies almost never test either metal or stone for radioactive contamination.

Radiation dumps in Moscow:

Acute problem - radioactive landfills. There are dozens of them in the city. In the fifties of the last century, under the leadership of L.P. Beria, active work began in Moscow on enriching uranium to create nuclear shield And research papers in the field of peaceful atom.

In densely populated areas of the capital, uranium enrichment centrifuges were installed; production and testing waste was transported outside the city and dumped in ravines, lowlands and covered with a meter-thick layer of soil. Or didn't fall asleep.

At that time, the city border passed immediately beyond the Moscow Ring Railway. That is, now it is almost the center of Moscow. The largest and industrial wastes are located near the Kashirskoye Highway, on the banks of the Moscow River. There are tens (according to some sources up to 800) thousand cubic meters of waste.

The difficulty of this section lies in the steepness of the coast and the volume of soil. If you start removing it, the existing soil structure will be disrupted, the bank will slide and radiation will fall into the river. It’s also impossible not to take it out - it rains and groundwater wash away radioactive rocks and contaminate the river.

A global problem are abandoned radioactive dumps. Enthusiasts and Authorized government bodies They are found in the capital by the dozens every year. There are radioactive equipment, disused medical devices and soil dumps here.

The danger is posed by the slope of the Moskva River, not far from MEPhI on Kashirka. A health hazard may occur if you stay there for more than an hour. In general, much has been said about the exceptional danger of radiation for the health of Muscovites (knowing about the overcrowding of people in Moscow and the presence of unprecedented large quantity"nuclear" enterprises), they plan to solve the problem with the help of the Radon enterprise

The most dangerous radiation dumps in Moscow

1. Bank of the Likhoborka River
2. in Troparevsky forest park
3. in Lyublino
4. in Krylatskoe
5. Wild radioactive waste dump - Zhostovo quarry 500 meters from the Pirogovskoye reservoir and 1500 meters from the Moscow canal

The radiation level in Moscow is 11-15 microroentgens (the norm is 30 microroentgens). In the metro the level is several times higher than normal. Experts consider it harmless, since the radiation here is natural; it is based on radon gas. However, it all depends on how long a person stays there.

All major nuclear facilities in Moscow are located in industrial zones. Check out full list dangerous enterprises and their location on maps of Moscow.

Radioactive objects in Moscow include

• 11 nuclear reactors
• 2000 organizations directly related to radiation sources (the number is increasing)
• 155 thousand (!!!) radiation sources
• 60 to 90 sources of radiation are discovered annually
• Special attention I would like to pay attention to the “Green Hill” section (Marshal Rokossovsky Boulevard). There is a radioactive burial ground here - more than two dozen sites. The excess of the norm is 150 times.
• More than 10 radiation source sites have been discovered in the Strogino area. The Radon company removed and buried more than 220 thousand radiation sources.
• The Moscow authorities have developed the program “Ensuring the Nuclear and Radiation Safety of Moscow for 2011 - 2013.” About 5 billion rubles were found for these purposes. Where do they plan to spend it?

Look at the maps of radiation dumps in Moscow.

Radiation map - waste disposal on the Likhoborka River

Radiation map - some wild radioactive waste dumps in Moscow

Full map radiation in Moscow can be viewed on the main page of the site on the map by clicking the buttons above the map “Radioactivity” and “Show”

Look at today's environmental situation Moscow and Moscow region -