Radioactive waste. Sources of appearance

Radioactive waste (RAW) is those substances that contain radioactive elements and cannot be reused in the future, since they have no practical value. They are formed during the mining and processing of radioactive ore, during the operation of equipment that generates heat, and during the disposal of nuclear waste.

Types and classification of radioactive waste

By type of radioactive waste they are divided:

• by state – solid, gaseous, liquid;
• by specific activity – highly active, medium activity, low active, very low activity
• by type – deleted and special;
• according to the half-life of radionuclides - long- and short-lived;
• by elements of nuclear type - with their presence, with their absence;
• in mining - during the processing of uranium ores, during the extraction of mineral raw materials.

This classification is relevant for Russia and is accepted at the international level. In general, the division into classes is not final, it requires coordination with different national systems.

Freed from control

There are types of radioactive waste that contain very low concentrations of radionuclides. They pose virtually no danger to environment. Such substances fall into the exempt category. The annual amount of radiation from them does not exceed 10 μ3v.

Rules for handling radioactive waste

Radioactive substances are divided into classes not only to determine the level of danger, but also to develop rules for handling them:

• it is necessary to ensure the protection of the person who works with radioactive waste;
• environmental protection from hazardous substances should be increased;
• control the waste disposal process;
• indicate the level of exposure at each burial site based on documents;
• control the accumulation and use of radioactive elements;
• in case of danger, accidents must be prevented;
• in extreme cases, all consequences must be eliminated.

What is the danger of radioactive waste?

To prevent such an outcome, all enterprises using radioactive elements are obliged to use filtration systems, control production activities, disinfect and dispose of waste. This helps prevent environmental disaster.

The level of danger of radioactive waste depends on several factors. First of all, this is the amount of waste in the atmosphere, the power of radiation, the area of ​​the contaminated territory, the number of people who live on it. Since these substances are deadly, in the event of an accident it is necessary to eliminate the disaster and evacuate the population from the territory. It is also important to prevent and stop the movement of radioactive waste to other territories.

Storage and transportation rules

An enterprise working with radioactive substances must ensure reliable waste storage. It involves the collection of radioactive waste and their transfer for disposal. The means and methods necessary for storage are established by documents. Special containers are made for them from rubber, paper and plastic. They are also stored in refrigerators and metal drums. Transportation of radioactive waste is carried out in special sealed containers. They must be securely secured in transport. Transportation can only be carried out by companies that have a special license for this.

Recycling

The choice of processing methods depends on the characteristics of the waste. Some types of waste are shredded and compacted to optimize waste volume. It is customary to burn certain residues in the oven. RW processing must meet the following requirements:

• isolation of substances from water and other products;
• eliminate exposure;
• isolate the impact on raw materials and minerals;
• assess the feasibility of processing.

Collection and removal

The collection and disposal of radioactive waste must be carried out in places where there are no non-radioactive elements. In this case, it is necessary to take into account the state of aggregation, category of waste, its properties, materials, half-life of radionuclides, and the potential threat of the substance. In this regard, it is necessary to develop a strategy for radioactive waste management.

Specialized equipment must be used for collection and removal. Experts say that these operations are possible only with medium and low active substances. During the process, every step must be controlled to prevent environmental disaster. Even a small mistake can lead to an accident, environmental pollution and the death of a huge number of people. It will take many decades to eliminate the influence of radioactive substances and restore nature.

Connoisseurs appreciate Fourier's champagne. It is obtained from grapes growing in the picturesque hills of Champagne. It's hard to believe that less than 10 km from the famous vineyards lies the largest radioactive waste storage facility. They are brought from all over France, delivered from abroad and buried for the next hundreds of years. The House of Fourier continues to make excellent champagne, the meadows are blooming around, the situation is controlled, complete cleanliness and safety are guaranteed in and around the landfill. Such a green lawn - the main objective construction of radioactive waste disposal sites.

Roman Fishman

No matter what some hotheads say, we can say with confidence that Russia is not in danger of turning into a global radioactive dump in the foreseeable future. A federal law passed in 2011 specifically prohibits the transport of such waste across borders. The ban applies in both directions, with the only exception concerning the return of radiation sources that were produced in the country and shipped abroad.

But even taking into account the law, nuclear energy produces little truly frightening waste. The most active and dangerous radionuclides are contained in spent nuclear fuel (SNF): fuel elements and assemblies in which they are placed emit even more strongly than fresh nuclear fuel and continue to generate heat. This is not waste, but a valuable resource; it contains a lot of uranium-235 and 238, plutonium and a number of other isotopes useful for medicine and science. All this makes up more than 95% of SNF and is successfully recovered at specialized enterprises - in Russia, this is primarily the famous Mayak Production Association in the Chelyabinsk region, where the third generation of reprocessing technologies is now being introduced, allowing 97% of SNF to be returned to work. Soon the production, operation and reprocessing of nuclear fuel will be closed into a single cycle that will not release virtually any hazardous substances.

However, even without spent nuclear fuel, the volume of radioactive waste will amount to thousands of tons per year. After all, sanitary rules require that everything that emits above a certain level or contains more than the required amount of radionuclides be included here. Almost any object that has been in contact with ionizing radiation for a long time falls into this group. Parts of cranes and machines that worked with ore and fuel, air and water filters, wires and equipment, empty containers and simply work clothes that have served their purpose and no longer have value. The IAEA (International Atomic Energy Agency) divides radioactive waste (RAW) into liquid and solid, into several categories, ranging from very low-level to high-level. And each has its own requirements for treatment.

RW classification

Class 1	Class 2	Class 3	Class 4	Class 5	Class 6
Solid				Liquid
Materials Equipment Products Solidified liquid radioactive waste HLW with high heat release	Materials Equipment Products Solidified liquid radioactive waste Low-heat HLW SAO are long-lived	Materials Equipment Products Solidified liquid radioactive waste SAO short-lived NAO are long-lived	Materials Equipment Products Biological objects Solidified liquid radioactive waste NAE is short-lived VLLW is long-lived	Organic and inorganic liquids SAO short-lived NAO are long-lived	RW generated during the mining and processing of uranium ores, mineral and organic raw materials with a high content of natural radionuclides
	Final isolation at deep burial sites with preliminary curing	Final isolation in deep burial sites at depths of up to 100 m	Final isolation at ground level near-surface disposal sites	Final isolation in existing deep disposal sites	Final isolation at near-surface disposal sites

Cold: recycling

The biggest environmental mistakes associated with the nuclear industry were made in the industry's early years. Not yet realizing all the consequences, the superpowers of the mid-twentieth century were in a hurry to get ahead of their competitors, to more fully master the power of the atom and did not pay much attention to waste management. However, the results of such a policy became obvious quite quickly, and already in 1957 the USSR adopted a decree “On measures to ensure safety when working with radioactive substances,” and a year later the first enterprises for their processing and storage opened.

Some of the enterprises are still operating today, already in the structures of Rosatom, and one retains its old “serial” name - “Radon”. One and a half dozen enterprises were transferred to the management of the specialized company RosRAO. Together with PA Mayak, the Mining and Chemical Combine and other Rosatom enterprises, they are licensed to handle radioactive waste of various categories. However, not only nuclear scientists resort to their services: radioactive substances are used for a variety of applications, from cancer treatment and biochemical research to the production of radioisotope thermoelectric generators (RTGs). And all of them, having served their purpose, turn into waste.

Most of them are low-level - and of course, over time, as short-lived isotopes decay, they become safer. Such waste is usually sent to prepared landfills for storage for tens or hundreds of years. They are pre-processed: what can burn is burned in ovens, purifying the smoke complex system filters. Ash, powders and other loose components are cemented or filled with molten borosilicate glass. Liquid waste of moderate volumes is filtered and concentrated by evaporation, extracting radionuclides from them with sorbents. Hard ones are crushed in presses. Everything is placed in 100 or 200 liter barrels and again pressed, placed in containers and cemented again. “Everything is very strict here,” the deputy told us. general director RusRAO Sergey Nikolaevich Brykin. “When handling radioactive waste, everything that is not permitted by licenses is prohibited.”

Special containers are used for transportation and storage of radioactive waste: depending on the activity and type of radiation, they can be reinforced concrete, steel, lead, or even boron-enriched polyethylene. They try to carry out processing and packaging on site using mobile complexes in order to reduce the difficulties and risks of transportation, partly with the help of robotic technology. Transportation routes are thought out and agreed upon in advance. Each container has its own identifier, and their fate is traced to the very end.

RW conditioning and storage center in Andreeva Bay on the shore Barents Sea works on the site of the former technical base of the Northern Fleet.

Warmer: storage

The RTGs we mentioned above are almost never used on Earth today. They once provided power to automatic monitoring and navigation points in remote and hard-to-reach locations. However, numerous incidents with leaks of radioactive isotopes into the environment and the banal theft of non-ferrous metals forced them to abandon their use anywhere other than spacecraft. The USSR managed to produce and assemble more than a thousand RTGs, which were dismantled and continue to be disposed of.

Even more problematic is the legacy of the Cold War: in decades alone nuclear submarines Almost 270 were built, and today less than fifty remain in service, the rest have been disposed of or are awaiting this complex and expensive procedure. In this case, the spent fuel is unloaded, and the reactor compartment and two adjacent ones are cut out. The equipment is removed from them, additionally sealed and left to be stored afloat. This has been done for years, and by the early 2000s in the Russian Arctic and in Far East About 180 radioactive “floats” were rusting. The problem was so acute that it was discussed at a meeting of the leaders of the countries " Big Eight", who agreed on international cooperation in cleaning the coast.

Dock pontoon for performing operations with reactor compartment blocks (85 x 31.2 x 29 m). Load capacity: 3500 t; draft when towing: 7.7 m; towing speed: up to 6 knots (11 km/h); service life: at least 50 years. Builder: Fincantieri. Operator: Rosatom. Location: Saida Guba in the Kola Bay, designed to store 120 reactor compartments.

Today, the blocks are lifted from the water and cleaned, the reactor compartments are cut out, and an anti-corrosion coating is applied to them. Treated packages are installed for long-term safe storage on prepared concrete sites. At the recently launched complex in Saida Guba in the Murmansk region, a hill was even demolished for this purpose, the rocky base of which provided reliable support for a storage facility designed for 120 compartments. Lined up in a row, the thickly painted reactors resemble a neat factory site or industrial equipment warehouse, watched over by an attentive owner.

This result of the elimination of dangerous radiation objects is called a “brown lawn” in the language of nuclear scientists and is considered completely safe, although not very aesthetically pleasing. The ideal target of their manipulations is a “green lawn”, like the one that stretches over the already familiar French CSA storage facility (Centre de stockage de l’Aube). A waterproof coating and a thick layer of specially selected turf turn the roof of a buried bunker into a clearing in which you just want to lie down, especially since it is allowed. Only the most dangerous radioactive waste is destined not for the “lawn”, but for the gloomy darkness of final burial.

Hot: burial

High-level radioactive waste, including spent fuel reprocessing waste, requires reliable isolation for tens and hundreds of thousands of years. Sending waste into space is too expensive, dangerous due to accidents during launch, and burial in the ocean or in faults in the earth's crust is fraught with unpredictable consequences. For the first years or decades they can still be kept in pools of “wet” above-ground storage facilities, but then something will have to be done with them. For example, transfer it to a safer and longer-term dry place - and guarantee its reliability for hundreds and thousands of years.

“The main problem of dry storage is heat transfer,” explains Sergey Brykin. “If there is no aqueous environment, high-level waste heats up, which requires special engineering solutions.” In Russia, such a centralized ground storage facility with a sophisticated passive air cooling system operates at the Mining and Chemical Combine near Krasnoyarsk. But this is only a half-measure: a truly reliable burial ground must be underground. Then it will be protected not only by engineering systems, but also by geological conditions, hundreds of meters of fixed and preferably waterproof rock or clay.

This underground dry storage facility has been in use since 2015 and continues to be built in parallel in Finland. In Onkalo, highly active radioactive waste and spent nuclear fuel will be locked in granite rock at a depth of about 440 m, in copper canisters, additionally insulated with bentonite clay, and for a period of at least 100 thousand years. In 2017, Swedish energy engineers from SKB announced that they would adopt this method and build their own “eternal” storage facility near Forsmark. In the United States, debate continues over the construction of the Yucca Mountain repository in the Nevada desert, which will go hundreds of meters into the volcanic mountain range. The general fascination with underground storage facilities can be viewed from another angle: such reliable and protected burial can become a good business.

Taryn Simon, 2015−3015. Glass, radioactive waste. Vitrification of radioactive waste seals it inside a solid, inert substance for millennia. American artist Taryn Simon used this technology in her work dedicated to the centenary of Malevich’s Black Square. The black glass cube with vitrified radioactive waste was created in 2015 for the Moscow Garage Museum and has since been stored on the territory of the Radon plant in Sergiev Posad. It will end up in a museum in about a thousand years, when it becomes finally safe for the public.

From Siberia to Australia

Firstly, in the future, technologies may require new rare isotopes, of which there are many in spent nuclear fuel. Methods for their safe, cheap extraction may also emerge. Secondly, many countries are ready to pay for the disposal of high-level waste now. Russia has nowhere to go: the highly developed nuclear industry needs a modern “eternal” repository for such dangerous radioactive waste. Therefore, in the mid-2020s, an underground research laboratory should open near the Mining and Chemical Combine.

Three vertical shafts will go into the gneiss rock, which is poorly permeable to radionuclides, and at a depth of 500 m a laboratory will be equipped where canisters with electrically heated simulators of radioactive waste packages will be placed. In the future, compressed medium- and high-level waste, placed in special packaging and steel canisters, will be placed in containers and cemented with a bentonite-based mixture. In the meantime, about one and a half hundred experiments are planned here, and only after 15-20 years of testing and safety justification, the laboratory will be converted into a long-term dry storage facility for radioactive waste of the first and second classes - in a sparsely populated part of Siberia.

The population of a country is an important aspect of all such projects. People rarely welcome the creation of radioactive waste disposal sites a few kilometers from their own home, and in densely populated Europe or Asia it is not easy to find a place for construction. Therefore, they are actively trying to interest such sparsely populated countries as Russia or Finland. Recently, Australia has joined them with its rich uranium mines. According to Sergei Brykin, the country has put forward a proposal to build an international burial ground on its territory under the auspices of the IAEA. The authorities expect that this will bring additional money and new technologies. But then Russia is definitely not in danger of becoming a global radioactive dump.

The article “Green lawn above the nuclear burial ground” was published in the magazine “Popular Mechanics” (No. 3, March 2018).

The Law on the Use of Nuclear Energy states that radioactive waste is substances, materials, devices and other equipment that contain high levels of radionuclides and have lost their consumer properties and are also unsuitable for reuse.

Under what circumstances is waste containing radioactive elements generated?

Radioactive waste is contained in nuclear fuel; it is formed during the operation of nuclear power plants; this is one of the main sources. They can also be obtained as a result:

• mining radioactive ore;
• ore processing;
• production of heat dissipation elements;
• disposal of spent nuclear fuel.

During the development of nuclear weapons by the Russian armed forces, radioactive waste was also generated, such actions as the production, conservation and liquidation of facilities that used this material did not rehabilitate previous work with this material. As a result, the country contains a lot of waste generated during the production of nuclear materials.

Navy, submarines, as well as civilian ships using nuclear reactors, also leave radioactive waste during their operation and even after their failure.

Work with radioactive waste in Russia is associated with the following industries:

• In the national economy, using isotope products.
• In medical or pharmaceutical institutions and laboratories.
• Chemical, metallurgical and other industrial processing industries.
• Carrying out scientific experiments and research using nuclear fuel or similar elements.
• Even security services, in particular customs control.
• Oil or gas production also requires the use of nuclear substances, which leave behind radioactive waste.

It is important to know. Spent nuclear fuel does not fall under the category of radioactive waste, according to Russian legislation.

Division into types

A decree from the Government of the Russian Federation made adjustments according to which radioactive waste can be:

• hard;
• liquid;
• gas of the like;

species. The classification of radioactive waste classifies all elements and substances containing radionuclides as solid, liquid and gas-like. An exception is possible only if the formation is not related to nuclear energy, and the content of radionuclides is due to the extraction or processing of natural minerals and organic raw materials from increased level radionuclides or near its natural source. Concentration, which is within acceptable standards established by the resolution Russian Government, does not exceed 1.

RW belonging to the “solid” type contains man-made radionuclides, from which sources such as closed enterprises working with such substances are excluded. They are divided into four categories:

• highly active;
• moderately inactive;
• low active;
• very low active.

RW arriving in a “liquid” state is divided into only three categories:

• highly active;
• moderately active;
• low active.

Closed, spent enterprises and factories that worked with radionuclides belong to other categories of radioactive waste.

RW classification

Exists the federal law, for the purpose of which, the classification of radioactive waste divides it into the following types:

• Removable are substances for which the risk associated with their impact on the environment does not increase. And in the event of their removal from the storage site for subsequent burial, the risk of their presence on the territory of their location does not exceed. This type requires quite large financial costs to perform all manipulations with it and prepare special equipment and train personnel of recycling organizations.
• Special - radioactive waste, this type exposes the environment to a very great danger, in the event of their extraction, transportation and further actions, for cleanup of the territory or disposal in another place. Manipulations with this type are also very expensive financial side. In cases with a similar species, it is safer and more economically profitable to carry out the burial process at their primary location.

Radioactive waste is classified depending on the following characteristics:

• Half-life of radionuclides - short-lived or long-lived.
• Specific activity – highly active, medium active and low active radioactive waste.
• Physical state - can be liquid, solid or gas-like.
• The content of nuclear elements is present or absent in the waste material.
• Spent, closed uranium mining or processing plants that emit ionizing rays.
• RW not related to the use or work on nuclear energy. The sources are processing enterprises for the extraction of organic and mineral raw materials ores, with an increased level of radionuclides of natural origin.

The classification of radioactive waste was developed by the Government Russian Federation, to divide them into types. As well as further removal or burial at their location.

Classification system

At this time, the classification system is not thoroughly developed and requires constant improvements, this is determined by the lack of consistency between national systems.

The basis of the classification contains consideration of options for subsequent disposal of radioactive waste. The main sign of this is the duration of the decay period of the nuclide, because the disposal technology directly depends on this indicator. They are buried with special strengthening solutions at least for the period during which they may be hazardous to the environment. According to these data, the classification system divides all waste and hazardous substances into the following categories.

Freed from control

Low active and medium active radioactive waste

They contain enough level radionuclides in order to pose a threat to personnel working with them and the population living in the immediate area. Sometimes they have such a high level of activity that they require cooling and the use of measures to protect against them. This category contains two groups: long-lived and short-lived species. The methods of their burial are very diverse and individual.

This type has such a quantity of radionuclides that it requires constant cooling while working with it. Upon completion of any actions, it requires reliable isolation from the biosphere, otherwise the infection process will take over the entire district in which it is located.

Typical characteristics

A controlled-exempt waste class (CW) has an activity level of 0.01 mSv or lower, taking into account the annual dose to the population. There are no restrictions on radiological disposal.

Medium and low active (LILW) are characterized by an activity level higher than the value for CW, but the heat release of this class is below 2W/m3.

Short-lived class (LILW-SL) – has these typical characteristics. The long-term viability of radionuclides has a limited concentration (less than 400 Bq/g for all packages). The burial places for such classes are deep or near-surface storage facilities.

Long-lived waste (LILW-LL) – the concentration of which is higher than that of short-lived waste. Such classes should be buried only in deep storage facilities. This is one of the main requirements in relation to them.

High-level class (HLW) - characterized by a very high concentration of long-lived radionuclides, their thermal output is more than 2 W/m3. Their burial places should also be deep storage facilities.

Rules for handling radioactive waste

Radioactive waste requires classification not only for the sake of dividing it according to the level of danger and the ability to choose disposal methods, but also to determine instructions for methods of handling it, depending on its class. They must meet the following indicators:

• Principles for ensuring the protection of human health, or at least an acceptable level of protection, depending on radiation exposure from radioactive waste elements.
• Environmental protection – an acceptable level of environmental protection from the effects of radioactive waste.
• Interdependence between all stages of the formation of radioactive waste, as well as the management of their elements.
• Protection of the future generation, by predicting the level of exposure, and rationing the amount of buried material at each burial site, based on information from regulatory documents.
• Do not place too high hopes on the future generation due to the need to dispose of radioactive waste.
• Control the formation and accumulation of radioactive waste, limit their accumulation and minimize the achieved level.
• Prevent accidents, or mitigate possible consequences, if such situations arise.

Radioactive waste is the most dangerous look debris on the ground, requiring very careful and careful handling. Causing the greatest damage to the environment, the population and all living beings on the territory of its foundation.

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Collection, modification and disposal of radioactive waste must be carried out separately from other types of waste materials. Dumping them into water bodies is prohibited, otherwise the consequences will be very sad. Radioactive waste is waste that has no practical value for further production. They include a collection of radioactive chemical elements. According to Russian legislation, subsequent use of such compounds is prohibited.

Before starting the disposal process, radioactive waste must be sorted according to the degree of radioactivity, form and decay period.

Subsequently, to reduce the volume of dangerous isotopes and neutralize radionuclides, they are processed through combustion, evaporation, pressing and filtration.

Subsequent treatment consists of fixing liquid waste with cement or bitumen for the purpose of solidification, or vitrification of highly active radioactive waste.

The fixed isotopes are placed in special, complexly designed containers with thick walls for their further transportation to the storage location. In order to increase safety, they are supplied with additional packaging.

general characteristics Radioactive waste can be generated from various sources and have a variety of different shapes

and properties.

• Important characteristics of radioactive waste include: Concentration. A parameter showing the value of specific activity. That is, this is the activity that accounts for one unit of mass. The most popular unit of measurement is Ci/T. Accordingly, the greater this characteristic, the more dangerous consequences
• may bring such rubbish with it.

Half life. The duration of the decay of half the atoms in a radioactive element. It is worth noting that the faster this period, the more energy the garbage releases, causing more harm, but in this case the substance loses its properties faster.

• Harmful substances can have different forms; there are three main physical states:
• Gaseous. As a rule, this includes emissions from ventilation units of organizations involved in the direct processing of radioactive materials.
• Solid form. These are glass and glassware from hospitals and research laboratories.

Storage of radioactive waste

The owner of a radioactive waste storage facility in Russia can be: entity, and the federal government. For temporary storage, radioactive waste must be placed in a special container that ensures the conservation of spent fuel. Moreover, the material from which the container is made should not enter into any chemical reaction with substance.

Storage premises must be equipped with dry drums, which allow short-lived radioactive waste to decay before further processing. Such a room is a radioactive waste storage facility. The purpose of its operation is the temporary placement of radioactive waste for further transportation to their disposal sites.

Container for solid radioactive waste

Disposal of radioactive waste cannot be done without a special container called a container for radioactive waste. A container for radioactive waste is a vessel used as a storage facility for radioactive waste. In Russia, the law establishes a huge number of requirements for such an invention.

The main ones:

1. The non-returnable container is not intended for storing liquid radioactive waste. Its structure allows it to contain only solid or hardened substances.
2. The body that the container has must be sealed and not allow even a small part of the stored waste to pass through.
3. After removing the cover and decontamination, contamination should not exceed 5 particles per m2. It is impossible to allow more pollution, since unpleasant consequences can also affect the external environment.
4. The container must withstand the harshest temperature conditions from - 50 to + 70 degrees Celsius.
5. When draining a radioactive substance from high temperature into a container, the container must withstand temperatures up to + 130 degrees Celsius.
6. The container must withstand external physical influences, in particular earthquakes.

The isotope storage process in Russia must ensure:

• Their isolation, compliance with protective measures, as well as monitoring the state of the environment. The consequences of violating such a rule can be disastrous, since the substances can almost instantly pollute nearby areas.
• Possibility of facilitating further procedures at subsequent stages.

The main directions of the toxic waste storage process are:

• Storage of radioactive waste with a short lifespan. Subsequently, they are discharged in strictly regulated volumes.
• Storage of high-level radioactive waste until disposal. This allows you to reduce the amount of heat they generate and reduce the consequences of harmful effects on the environment.

Disposal of radioactive waste

Problems with radioactive waste disposal still exist in Russia. Not only the environmental protection of humans, but also the environment must be ensured. This type of activity presupposes the availability of a license for the use of subsoil and the right to carry out work on the development of nuclear energy.

Radioactive waste disposal facilities can be either federally owned or owned by the state corporation Rosatom. Today, radioactive waste is buried in the Russian Federation in specially designated places called radioactive waste repositories.

1. There are three types of disposal, their classification depends on the duration of storage of radioactive substances:
2. Long-term disposal of radioactive waste - ten years. Harmful elements are buried in trenches, small engineering structures made on or under the ground.
3. For hundreds of years. In this case, the disposal of radioactive waste is carried out in the geological structures of the continent, which includes underground workings and natural cavities. In Russia and other countries, they actively practice the creation of burial grounds on the ocean floor.

Transmutation. A theoretically possible way to get rid of radioactive substances, which involves irradiating long-lived radionuclides and turning them into short-lived ones.

• The type of burial is selected based on three parameters:
• Specific activity of a substance
• Packaging sealing level

Estimated shelf life

1. Radioactive waste storage facilities in Russia must meet the following requirements:
2. The radioactive waste storage facility should be located away from the city. The distance between them must be at least 20 kilometers. The consequences of violating this rule are poisoning and possible death of the population.
3. There should be no built-up areas near the burial site, otherwise there is a risk of damage to the containers.
4. There must be an area adjacent to the landfill where waste will be buried.
5. The level of ground sources should be as far away as possible. If waste gets into the water, the consequences will be sad - the death of animals and humans Radioactive burial grounds for solid and other waste must have sanitary. Its length cannot be less than 1 kilometer from livestock grazing areas and populated areas.
6. At the landfill there should be a plant engaged in the detoxification of radioactive waste.

Recycling

Reprocessing of radioactive waste is a procedure that is aimed at direct transformation state of aggregation or properties of a radioactive substance, in order to create convenience for the transportation and storage of waste.

Each type of waste has its own methods for carrying out such a procedure:

• For liquids - precipitation, exchange using ions and distillation.
• For solids – combustion, pressing and calcination. The remaining solid waste is sent to disposal sites.
• For gases - chemical absorption and filtration. Substances will then be stored in high-pressure cylinders.

Regardless of which unit the product is processed, the end result will be immobilized compact blocks of solid types. For immobilization and further isolation of solids, the following methods are used:

• Cementing. Used for waste with low and medium activity of the substance. As a rule, this is solid waste.
• Burning at high temperatures.
• Vitrification.
• Packaging in special containers. Typically these containers are made of steel or lead.

Deactivation

Due to active environmental pollution, in Russia and other countries of the world they are trying to find an up-to-date method for decontaminating radioactive waste. Yes, the burial and disposal of solid radioactive waste produces results, but unfortunately, these procedures do not ensure environmental safety, and therefore are not perfect. Currently, several methods of radioactive waste decontamination are practiced in Russia.

Using sodium carbonate

This method is used exclusively for solid waste that has entered the soil: sodium carbonate leaches radionuclides, which are extracted from the alkali solution by ion particles that include magnetic material. Next, the chelate complexes are removed using a magnet. This method of processing solids is quite effective, but there are disadvantages.

Method problem:

• The lixiviant (formula Na2Co3) has a fairly limited chemical ability. He is simply not able to extract the entire range of radioactive compounds from solid state and convert them into liquid materials.
• The high cost of the method is mainly due to the chemisorption material, which has a unique structure.

Dissolution in nitric acid

Let's apply the method to radioactive pulps and sediments; these substances are dissolved in nitric acid mixed with hydrazine. After this, the solution is packaged and vitrified.

The main problem is the high cost of the procedure, since the evaporation of the solution and further disposal of radioactive waste is quite expensive.

Soil elution

Used for decontamination of soil and ground. This method is the most environmentally friendly. The bottom line is this: contaminated soil or soil is treated by elution with water, aqueous solutions with additions of ammonium salts, and ammonia solutions.

The main problem is the relatively low efficiency in extracting radionuclides that are bound to the soil at the chemical level.

Decontamination of liquid waste

Liquid radioactive waste is a special type of waste that is difficult to store and dispose of. That is why decontamination is the best means of getting rid of such a substance.

There are three ways to clean harmful material from radionuclides:

1. Physical method. Refers to the process of evaporation or freezing of substances. Next, the hazardous elements are sealed and placed in waste repositories.
2. Physico-chemical. Extraction is carried out using a solution with selective extractants, i.e. removal of radionuclides.
3. Chemical. Purification of radionuclides using various natural reagents. The main problem of this method is the large amount of remaining sludge that is sent to landfills.

Common problem with each method:

• Physical methods - extremely high costs for evaporation and freezing of solutions.
• Physico-chemical and chemical - huge volumes of radioactive sludge sent to burial sites. The burial procedure is quite expensive, it requires a lot of money and time.

Radioactive waste is a problem not only in Russia, but also in other countries. The main task of humanity at the moment is the disposal of radioactive waste and its disposal. Each state decides independently how to do this.

Switzerland does not independently reprocess and dispose of radioactive waste, but is actively developing programs for the management of such waste. If you do not take any action, the consequences can be the most tragic, including the death of humanity and animals.

Radioactive waste

Radioactive waste (RAO) - waste containing radioactive isotopes of chemical elements and having no practical value.

According to the Russian “Law on the Use of Atomic Energy” (No. 170-FZ dated November 21, 1995), radioactive waste (RAW) is nuclear materials and radioactive substances, the further use of which is not envisaged. According to Russian legislation, the import of radioactive waste into the country is prohibited.

Radioactive waste and spent nuclear fuel are often confused and considered synonymous. These concepts should be distinguished. Radioactive waste is materials that are not intended to be used. Spent nuclear fuel is a fuel element containing residual nuclear fuel and a variety of fission products, mainly 137 Cs and 90 Sr, widely used in industry, agriculture, medicine and scientific activity. Therefore, it is a valuable resource, as a result of its processing, fresh nuclear fuel and isotope sources are obtained.

Sources of waste

Radioactive waste is generated in various forms with very different physical and chemical characteristics, such as the concentrations and half-lives of their constituent radionuclides. This waste can be generated:

• in gaseous form, such as ventilation emissions from installations where radioactive materials are processed;
• in liquid form, ranging from scintillation counter solutions from research facilities to liquid high-level waste generated during spent fuel reprocessing;
• in solid form (contaminated consumables, glassware from hospitals, medical research facilities and radiopharmaceutical laboratories, vitrified waste from fuel reprocessing or spent fuel from nuclear power plants when it is considered waste).

Examples of sources of radioactive waste in human activity:

Work with such substances is regulated sanitary rules, issued by Sanitary and Epidemiological Supervision.

• Coal . Coal contains small amounts of radionuclides such as uranium or thorium, but the content of these elements in coal is less than their average concentration in the earth's crust.

Their concentration increases in fly ash, since they practically do not burn.

However, the radioactivity of ash is also very small, it is approximately equal to the radioactivity of black shale and less than that of phosphate rocks, but it poses a known danger, since some amount of fly ash remains in the atmosphere and is inhaled by humans. At the same time, the total volume of emissions is quite large and amounts to the equivalent of 1000 tons of uranium in Russia and 40,000 tons worldwide.

Classification

Conventionally radioactive waste is divided into:

• low-level (divided into four classes: A, B, C and GTCC (the most dangerous);
• medium-level (US legislation does not distinguish this type of radioactive waste into a separate class; the term is mainly used in European countries);
• highly active.

US legislation also distinguishes transuranium radioactive waste. This class includes waste contaminated with alpha-emitting transuranium radionuclides with half-lives of more than 20 years and concentrations greater than 100 nCi/g, regardless of their form or origin, excluding highly active radioactive waste. Due to the long period of decay of transuranic waste, their disposal is more thorough than the disposal of low-level and intermediate-level waste. Also Special attention This class of waste is allocated because all transuranium elements are artificial and the behavior of some of them in the environment and in the human body is unique.

Below is the classification of liquid and solid radioactive waste in accordance with the “Basic sanitary rules for ensuring radiation safety” (OSPORB 99/2010).

One of the criteria for such classification is heat generation. Low-level radioactive waste has extremely low heat generation. For medium-active ones, it is significant, but active heat removal is not required. High-level radioactive waste generates so much heat that it requires active cooling.

Radioactive waste management

Initially, it was believed that a sufficient measure was the dispersion of radioactive isotopes in the environment, by analogy with industrial waste in other industries. At the Mayak enterprise, in the first years of operation, all radioactive waste was dumped into nearby reservoirs. As a result, the Techa cascade of reservoirs and the Techa River itself became polluted.

Later it turned out that due to natural and biological processes radioactive isotopes are concentrated in certain subsystems of the biosphere (mainly in animals, in their organs and tissues), which increases the risk of irradiation of the population (due to the movement of large concentrations of radioactive elements and their possible entry into the human body with food). Therefore, the attitude towards radioactive waste has changed.

1) Protection of human health. Radioactive waste is managed in such a way as to ensure an acceptable level of protection of human health.

2) Environmental protection. Radioactive waste is managed in such a way as to ensure an acceptable level of environmental protection.

3) Protection beyond national borders. Radioactive waste is managed in a manner that takes into account possible consequences for human health and the environment beyond national borders.

4) Protection of future generations. Radioactive waste is managed in such a way that the foreseeable consequences for the health of future generations do not exceed the appropriate levels of consequences that are acceptable today.

5) Burden for future generations. Radioactive waste is managed in such a way as not to impose undue burden on future generations.

6) National legal structure. Radioactive waste management is carried out within the framework of an appropriate national legal framework, which provides for a clear division of responsibilities and independent regulatory functions.

7) Control over the generation of radioactive waste. The generation of radioactive waste is kept to the minimum practicable level.

8) Interdependencies between the generation of radioactive waste and their management. The interdependencies between all stages of radioactive waste generation and management are duly taken into account.

9) Installation safety. The safety of radioactive waste management facilities is adequately ensured throughout their service life.

Main stages of radioactive waste management

• At storage radioactive waste should be contained in such a way that:
  • their isolation, protection and environmental monitoring were ensured;
  • If possible, actions at subsequent stages (if provided) were facilitated.

In some cases, storage may be primarily for technical reasons, such as the storage of radioactive waste containing primarily short-lived radionuclides for the purpose of decay and subsequent discharge within authorized limits, or the storage of high-level radioactive waste prior to disposal in geological formations in order to reduce heat generation.

• Preliminary processing waste is the initial stage of waste management. This includes collection, chemical control and decontamination and may include a period of interim storage. This stage is very important, since in many cases during pre-processing it appears best opportunity to separate waste streams.

• Treatment radioactive waste includes operations whose purpose is to improve safety or economy by changing the characteristics of radioactive waste. Basic processing concepts: volume reduction, radionuclide removal and composition modification. Examples:
  • burning of combustible waste or compaction of dry solid waste;
  • evaporation, filtration or ion exchange of liquid waste streams;
  • sedimentation or flocculation of chemicals.

Radioactive waste capsule

• Conditioning radioactive waste consists of operations in which radioactive waste is given a form suitable for movement, transportation, storage and disposal. These operations may include immobilizing radioactive waste, placing the waste in containers, and providing additional packaging. Common immobilization methods include solidification of liquid low- and intermediate-level radioactive waste by embedding it in cement (cementing) or bitumen (bitumenization), and vitrification of liquid radioactive waste. Immobilized waste, in turn, depending on the nature and its concentration, can be packaged in various containers, ranging from ordinary 200-liter steel barrels to complexly designed containers with thick walls. In many cases, processing and conditioning are carried out in close conjunction with each other.

• Burial Basically, radioactive waste is placed in a disposal facility under appropriate security conditions without the intention of its removal and without long-term surveillance and maintenance of the repository. Safety is primarily achieved through concentration and containment, which involves isolating properly concentrated radioactive waste in a disposal facility.

Technologies

Management of intermediate level radioactive waste

Typically in the nuclear industry, intermediate level radioactive waste is subjected to ion exchange or other methods whose purpose is to concentrate radioactivity in a small volume. After processing, the much less radioactive body is completely neutralized. It is possible to use iron hydroxide as a flocculant to remove radioactive metals from aqueous solutions. After the radioisotopes are absorbed by iron hydroxide, the resulting precipitate is placed in a metal drum, where it is mixed with cement to form a solid mixture. For greater stability and durability, concrete is made from fly ash or furnace slag and Portland cement (as opposed to ordinary concrete, which consists of Portland cement, gravel and sand).

Management of high-level radioactive waste

Removal of low-level radioactive waste

Transportation of flasks with high-level radioactive waste by train, Great Britain

Storage

For the temporary storage of high-level radioactive waste, tanks for storing spent nuclear fuel and storage facilities with dry drums are intended, allowing short-lived isotopes to decay before further processing.

Vitrification

Long-term storage of radioactive waste requires conservation of waste in a form that will not react or degrade over a long period of time. One way to achieve this state is vitrification (or vitrification). Currently, in Sellafield (UK), highly active RW (purified products of the first stage of the Purex process) are mixed with sugar and then calcined. Calcination involves passing the waste through a heated rotating tube and aims to evaporate water and denitrogenize the fission products to increase the stability of the resulting glassy mass.

Crushed glass is constantly added to the resulting substance, located in an induction furnace. The result is a new substance in which, when hardened, the waste binds to the glass matrix. This substance in a molten state is poured into alloy steel cylinders. As the liquid cools, it hardens into glass, which is extremely resistant to water. According to the International Technology Society, it would take about a million years for 10% of such glass to dissolve in water.

After filling, the cylinder is brewed and then washed. After inspection for external contamination, the steel cylinders are sent to underground storage facilities. This state of waste remains unchanged for many thousands of years.

The glass inside the cylinder has a smooth black surface. In the UK, all work is done using highly active substance chambers. Sugar is added to prevent the formation volatile substance RuO 4 containing radioactive ruthenium. In the West, borosilicate glass, identical in composition to Pyrex, is added to waste; In the countries of the former USSR, phosphate glass is usually used. The amount of fission products in glass must be limited, since some elements (palladium, platinum group metals, and tellurium) tend to form metal phases separate from the glass. One of the vitrification plants is located in Germany, where waste from a small demonstration processing factory that has ceased to exist is processed.

In 1997, in the 20 countries with most of the world's nuclear potential, spent fuel stockpiles in storage facilities inside reactors amounted to 148 thousand tons, 59% of which were disposed of. External storage facilities contained 78 thousand tons of waste, of which 44% was recycled. Taking into account the rate of recycling (about 12 thousand tons annually), the final elimination of waste is still quite far away.

Geological burial

The search for suitable sites for deep final disposal of waste is currently underway in several countries; The first such storage facilities are expected to come into operation after 2010. The international research laboratory in Grimsel, Switzerland, deals with issues related to the disposal of radioactive waste. Sweden is talking about its plans for direct disposal of used fuel using KBS-3 technology, after the Swedish parliament deemed it safe enough. In Germany, discussions are currently underway about finding a place for permanent storage of radioactive waste; residents of the village of Gorleben in the Wendland region are actively protesting. This location, until 1990, seemed ideal for the disposal of radioactive waste due to its proximity to the borders of the former German Democratic Republic. Now the radioactive waste is in temporary storage in Gorleben; a decision on the location of its final disposal has not yet been made. US authorities chose Yucca Mountain, Nevada as the burial site, however this project met with strong opposition and became a topic of heated debate. There is a project to create an international storage facility for high-level radioactive waste; Australia and Russia are proposed as possible disposal sites. However, Australian authorities oppose such a proposal.

There are projects for disposal of radioactive waste in the oceans, including disposal under the abyssal zone of the seabed, disposal in a subduction zone, as a result of which the waste will slowly sink to the earth's mantle, as well as disposal under a natural or artificial island. These projects have obvious advantages and will help solve the unpleasant problem of radioactive waste disposal at the international level, but despite this, they are currently frozen due to prohibitive provisions maritime law. Another reason is that in Europe and North America there are serious concerns about leakage from such a storage facility, which will lead to an environmental disaster. The real possibility of such a danger has not been proven; however, the bans were strengthened after the dumping of radioactive waste from ships. However, in the future, countries that cannot find other solutions to this problem may seriously think about creating ocean storage facilities for radioactive waste.

In the 1990s, several options for conveyor disposal of radioactive waste into the bowels were developed and patented. The technology was supposed to be as follows: a large-diameter starting well with a depth of up to 1 km is drilled, a capsule loaded with radioactive waste concentrate weighing up to 10 tons is lowered inside, the capsule should self-heat and in the form of “ fireball» melt through the earth's rock. After the first “fireball” is deepened, a second capsule should be lowered into the same hole, then a third, etc., creating a kind of conveyor.

Reuse of radioactive waste

Another use for isotopes contained in radioactive waste is their reuse. Already, cesium-137, strontium-90, technetium-99 and some other isotopes are used for irradiation food products and ensure the operation of radioisotope thermoelectric generators.

Removal of radioactive waste into space

Sending radioactive waste into space is a tempting idea because radioactive waste is permanently removed from the environment. However, such projects have significant drawbacks, one of the most important is the possibility of a launch vehicle accident. In addition, the significant number of launches and their high cost make this proposal impractical. The matter is also complicated by the fact that the international agreements about this problem.

Nuclear fuel cycle

Start of the cycle

Waste initial period nuclear fuel cycle - usually waste rock produced from uranium extraction that emits alpha particles. It usually contains radium and its decay products.

The main byproduct of enrichment is depleted uranium, consisting primarily of uranium-238, with less than 0.3% uranium-235. It is stored in the form of UF 6 (waste uranium hexafluoride) and can also be converted into the form of U 3 O 8 . IN small quantities Depleted uranium is used in applications where its extremely high density is valued, such as yacht keels and anti-tank shells. Meanwhile, several million tons of waste uranium hexafluoride have accumulated in Russia and abroad, and there are no plans for its further use in the foreseeable future. Waste uranium hexafluoride can be used (together with reused plutonium) to create mixed oxide nuclear fuel (which may be in demand if the country builds large quantities of fast neutron reactors) and to dilute highly enriched uranium previously included in nuclear weapons. This dilution, also called depletion, means that any country or group that acquires nuclear fuel will have to repeat the very expensive and complex enrichment process before it can create a weapon.

End of cycle

Substances that have reached the end of the nuclear fuel cycle (mostly spent fuel rods) contain fission products that emit beta and gamma rays. They may also contain actinides that emit alpha particles, which include uranium-234 (234 U), neptunium-237 (237 Np), plutonium-238 (238 Pu) and americium-241 (241 Am), and sometimes even sources neutrons such as californium-252 (252 Cf). These isotopes are formed in nuclear reactors.

It is important to distinguish between the processing of uranium to produce fuel and the reprocessing of used uranium. Used fuel contains highly radioactive fission products. Many of them are neutron absorbers, thus receiving the name “neutron poisons.” Ultimately, their number increases to such an extent that, by trapping neutrons, they stop the chain reaction even if the neutron absorber rods are completely removed.

Fuel that has reached this state must be replaced with fresh fuel, despite the still sufficient amount of uranium-235 and plutonium. Currently in the US, used fuel is sent to storage. In other countries (in particular, in Russia, Great Britain, France and Japan), this fuel is processed to remove fission products, and then after additional enrichment it can be reused. In Russia, such fuel is called regenerated. The reprocessing process involves working with highly radioactive substances, and the fission products removed from the fuel are a concentrated form of highly active radioactive waste, just like the chemicals used in reprocessing.

To close the nuclear fuel cycle, it is proposed to use fast neutron reactors, which make it possible to recycle fuel that is waste from thermal neutron reactors.

On the issue of nuclear weapons proliferation

When working with uranium and plutonium, the possibility of using them in the creation of nuclear weapons is often considered. Active nuclear reactors and stockpiles of nuclear weapons are carefully guarded. However, high-level radioactive waste from nuclear reactors may contain plutonium. It is identical to the plutonium used in reactors, and consists of 239 Pu (ideal for making nuclear weapons) and 240 Pu (an undesirable component, highly radioactive); these two isotopes are very difficult to separate. Moreover, high-level radioactive waste from reactors is full of highly radioactive fission products; however, most of them are short-lived isotopes. This means that the waste can be buried, and after many years the fission products will decay, reducing the radioactivity of the waste and making the plutonium easier to handle. Moreover, the unwanted isotope 240 Pu decays faster than 239 Pu, so the quality of weapons raw materials increases over time (despite the decrease in quantity). This raises controversy over the possibility that over time, waste storage facilities could turn into plutonium mines of sorts, from which raw materials for weapons could be relatively easily extracted. Against these assumptions is the fact that the half-life of 240 Pu is 6560 years, and the half-life of 239 Pu is 24110 years, thus, the comparative enrichment of one isotope relative to the other will occur only after 9000 years (this means that during this time the proportion of 240 Pu in a substance consisting of several isotopes will independently decrease by half - a typical transformation of reactor plutonium into weapons-grade plutonium). Consequently, if “weapons-grade plutonium mines” become a problem, it will only be in the very distant future.

One solution to this problem is to reuse recycled plutonium as fuel, for example in fast nuclear reactors. However, the very existence of nuclear fuel regeneration plants, necessary to separate plutonium from other elements, creates the possibility of nuclear weapons proliferation. In pyrometallurgical fast reactors, the resulting waste has an actinoid structure, which does not allow it to be used to create weapons.

Nuclear weapons reprocessing

Waste from the reprocessing of nuclear weapons (as opposed to their manufacture, which requires primary raw materials from reactor fuel) does not contain sources of beta and gamma rays, with the exception of tritium and americium. They contain much larger number actinides that emit alpha rays, such as plutonium-239, which undergoes nuclear reaction in bombs, as well as some substances with high specific radioactivity, such as plutonium-238 or polonium.

In the past, beryllium and highly active alpha emitters such as polonium have been proposed as nuclear weapons in bombs. Now an alternative to polonium is plutonium-238. For reasons state security, detailed designs of modern bombs are not covered in the literature accessible to a wide range of readers.

Some models also contain (RTG), in which a long-lasting source electrical power Plutonium-238 is used to operate the bomb's electronics.

It is possible that the fissile material of the old bomb to be replaced will contain decay products of plutonium isotopes. These include alpha-emitting neptunium-236, formed from inclusions of plutonium-240, as well as some uranium-235, derived from plutonium-239. The amount of this waste radioactive decay There will be very few bomb cores, and in any case they are much less dangerous (even in terms of radioactivity as such) than plutonium-239 itself.

As a result of the beta decay of plutonium-241, americium-241 is formed, an increase in the amount of americium - a big problem, than the decay of plutonium-239 and plutonium-240, since americium is a gamma emitter (its external influence workers) and an alpha emitter that can generate heat. Plutonium can be separated from americium in a variety of ways, including pyrometric treatment and aqueous/organic solvent extraction. Modified technology for extracting plutonium from irradiated uranium (PUREX) is also one of the possible separation methods.

In popular culture

In reality, the impact of radioactive waste is described by the impact ionizing radiation on the substance and depends on their composition (what radioactive elements are included in the composition). Radioactive waste does not acquire any new properties and does not become more dangerous because it is waste. Their greater danger is due only to the fact that their composition is often very diverse (both qualitatively and quantitatively) and sometimes unknown, which complicates the assessment of the degree of their danger, in particular, the doses received as a result of an accident.

see also

Notes

Links

• Safety when handling radioactive waste. General provisions. NP-058-04
• Key Radionuclides and Generation Processes (unavailable link)
• Belgian Nuclear Research Center - Activities (unavailable link)
• Belgian Nuclear Research Center - Scientific Reports (unavailable link)
• International Atomic Energy Agency - Nuclear Fuel Cycle and Waste Technology Program (unavailable link)
• (unavailable link)
• Nuclear Regulatory Commission - Spent Fuel Heat Generation Calculation (unavailable link)