What type of contamination is radioactive waste? Nuclear waste disposal

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 science. 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 occurs in a variety of forms with widely varying 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 by sanitary rules issued by the Sanitary and Epidemiological Supervision Authority.

• 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 the 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 greater 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 is given to this class of waste 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 produces 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 with food into the human body). Therefore, attitudes towards radioactive waste have 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 a manner that does not 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. Due consideration is given to the interdependencies between all stages of radioactive waste generation and management.

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 for the purpose of reducing 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 step is very important because in many cases pre-treatment provides the 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, 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 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 a 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 of the volatile substance RuO 4, which contains 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, but the 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 of maritime law. Another reason is that in Europe and North America there are serious fears of a leak 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 a concentrate of radioactive waste weighing up to 10 tons is lowered inside, the capsule should self-heat and melt the earth's rock in the form of a “fireball”. 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 now, cesium-137, strontium-90, technetium-99 and some other isotopes are used to irradiate 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 disadvantages, 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 international agreements regarding this problem have not yet been reached.

Nuclear fuel cycle

Start of the cycle

Front end waste of the nuclear fuel cycle is typically 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 numbers of actinides that emit alpha rays, such as plutonium-239, which undergoes nuclear reactions 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 of national security, detailed designs of modern bombs are not covered in the literature available to the general public.

Some models also contain (RTGs), which use plutonium-238 as a long-lasting source of electrical power 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 from the radioactive decay of the bomb core will be very small, and in any case it is 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 is a bigger problem than the decay of plutonium-239 and plutonium-240, since americium is a gamma emitter (its external impact on workers increases) and an alpha emitter, capable of generating 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 effect of ionizing radiation on a substance and depends on its 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)

Removal, processing and disposal of waste from hazard classes 1 to 5

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Radioactive waste is a substance unsuitable for further activities, containing large quantities of hazardous elements.

Various natural and man-made sources of radiation provoke the emergence of hazardous waste. Such debris is generated during the following processes:

• when creating nuclear fuel
• operation of a nuclear reactor
• radiation treatment of fuel elements
• production, as well as use of natural or artificial radioisotopes

The collection and further management of radioactive waste is established by the legislation of the Russian Federation.

Classification

In Russia, the classification of radioactive waste is based on Federal Law No. 190 of July 11, 2011, which regulates the collection and management of radioactive waste.

Radioactive waste can be of the following types:

• Deletable. The risk that may arise during the extraction and further use of hazardous waste. These costs should not be higher than the risk associated with the creation of a repository on the territory of the country.
• Special. A risk that includes possible exposure to hazardous radiation, as well as other risks based on the removal from storage and subsequent use of the elements. Must exceed the risks associated with their burial on the site.

The criteria by which the distribution is made are established by the Russian Government.

Radioactive waste is classified according to the following criteria:

Half-life of radionuclides, these include:

• long-lived
• short-lived

Specific activity. So, depending on the degree of activity, radioactive waste is usually divided into:

• Weakly active, the concentration of beta-emitting radioisotopes reaches 10 - 5 curies / l in such a substance.
• Medium activity, the concentration of beta-emitting radioisotopes reaches more than 1 curie / l.
• Low activity.
• Very low activity.

State. There are three types of such garbage:

• LRW (liquid radioactive waste)
• Solid

Presence of nuclear type elements:

• Availability
• absence

It is also customary to highlight:

• Materials formed during the mining (processing) of uranium ores.
• Materials formed as a result of the extraction of mineral (organic) raw materials not associated with the use of nuclear energy.

Danger

This waste is extremely dangerous for nature, as it increases the level of background radioactivity. There is also a danger of harmful substances entering the human body through consumed food and water. The result is mutation, poisoning or death.

That is why enterprises are recommended to use all kinds of filters in order to prevent harmful debris from entering the external environment. Currently, legislation requires the installation of special cleaners that collect harmful elements.

The level of radiation hazard depends on:

• Amounts of radioactive waste in the biosphere.
• The dose rate of gamma radiation present.
• Area of ​​territory exposed to pollution.
• Population size.

Radioactive waste is dangerous due to its penetration into the human body. Because of this, it is necessary to localize such mining in the territory of their formation. It is very important to prevent the possible migration of these raw materials through existing animal and human food chains.

Storage and transportation

• Storage of radioactive waste. Storage involves the collection and subsequent transfer of harmful elements for processing or disposal.
• Burial is the placement of waste in burial grounds. In this way, hazardous waste is removed from the scope of human activity and does not pose a danger to the environment.

It is worth noting that only solid and solidified waste can be sent to burial grounds for storage. The period of radioactive hazard of waste must be lower than the “lifetime” of engineering structures in which storage and disposal take place.

The following features associated with the disposal of hazardous waste should also be taken into account:

• Only radioactive waste with a possible threat life of no more than 500 years will be sent for disposal in a remote area.
• Waste, the danger period of which does not exceed several decades, can be stopped for storage on its territory without being sent for disposal.

The maximum amount of hazardous waste sent for storage is established based on an assessment of the safety of the repository. Methods and means for determining the permissible waste content in a special room can be found in regulatory documents.

Containers for this waste are disposable bags made from the following elements:

• rubber
• plastic
• paper

Collection, storage, transportation and further handling of radioactive waste packaged using such containers are carried out in specially equipped transport containers. Premises intended for storing these containers must be equipped with protective screens, refrigerators or containers.

There is a large list of storage options for various radioactive waste:

• Refrigerators. They are designed to contain the corpses of laboratory animals, as well as other organic materials.
• Metal drums. Dust-like radioactive waste is placed in them and the lids are sealed.
• Waterproof paint. It covers laboratory equipment for transportation.

Recycling

Treatment of radioactive waste is possible using several methods; the choice of method depends on the type of waste that will be processed.

Disposal of radioactive waste:

• They are crushed and pressed. This is necessary to optimize the volume of raw materials, as well as to reduce activity.
• They are burned in furnaces that are used to dispose of flammable residues.

The processing of radioactive waste must comply with the hygienic requirements:

1. 100% guaranteed insulation from food and water.
2. No external exposure exceeding the permissible level.
3. No negative impact on mineral deposits.
4. Performing economically feasible actions.

Collection and removal

Collection and sorting for further destruction of these wastes must be carried out in the places where they appear, separately from non-radioactive substances.

In this case, the following must be taken into account:

• Aggregate state of a harmful substance.
• Substance category.
• The amount of material that needs to be collected.
• Each property of a substance (chemical and physical).
• Approximate half-life of radionuclides. Typically, the measurement is presented in days, that is, more than 15 days or less than 15 days.
• Potential hazard of the substance (fire or explosion hazard).
• Future management of radioactive waste.

It is worth noting an important point - collection and disposal can only be done with low and medium active types of waste.

NRAW - low level radioactive waste are ventilation emissions that can be removed through a pipe and subsequently dissipated. According to the DKB standard, which was established by the national operator for radioactive waste management, there is a parameter for the height and conditions of the release.

The DKB value is calculated as follows: the ratio of the limit of the annual intake of a substance to a specific volume of water (usually 800 liters) or air (8 million liters). In this case, the DCS parameter is the limit of the annual intake of harmful substances (radionuclides) into the human body through water and air.

Intermediate level and liquid waste treatment

The collection and removal of medium-level radioactive substances is carried out using special devices:

• Gas tanks. A technology whose task is to receive, store and subsequently release gas. The main feature is that waste with a low half-life (1 - 4 hours) will be contained in the device exactly as long as it takes to completely decontaminate the harmful substance.
• Adsorption columns. The device is designed for more complete removal (about 98%) of radioactive gases. The decontamination scheme is as follows: the gas is cooled with the process of moisture separation, followed by deep drying in the columns themselves and the supply of the substance to the adsorber, which contains coal to absorb harmful elements.

Liquid radioactive waste is usually treated by evaporation. It is an ion exchange of two stages with preliminary purification of the substance from harmful impurities.

There is another way - liquid waste that is hazardous to the environment can be cleaned using rubber irradiation units. In most cases, a Co-60 type irradiator is used, which was stored in water.

After the ban on nuclear weapons testing in three areas, the problem of destroying radioactive waste generated during the use of atomic energy for peaceful purposes occupies one of the first places among all problems of radiation ecology.

Based on their physical state, radioactive waste (RAW) is divided into solid, liquid and gaseous.

According to OSPORB-99 (Basic Sanitary Rules for Radiation Safety), solid radioactive waste includes spent radionuclide sources, materials, products, equipment, biological objects, soil not intended for further use, as well as solidified liquid radioactive waste, in which the specific activity radionuclides are greater than the values ​​given in Appendix P-4 NRB-99 (radiation safety standards). If the radionuclide composition is unknown, materials with a specific activity greater than:

100 kBq/kg – for beta radiation sources;

10 kBq/kg – for alpha radiation sources;

1 kBq/kg – for transuranium radionuclides (chemical radioactive elements located in the periodic table of elements after uranium, i.e. with an atomic number greater than 92. All of them are obtained artificially, and only Np and Pu are found in nature in extremely small quantities).

Liquid radioactive waste includes organic and inorganic liquids, pulps and sludges that are not subject to further use, in which the specific activity of radionuclides is more than 10 times higher than the intervention levels when entering with water, given in Appendix P-2 NRB-99.

Gaseous radioactive waste includes radioactive gases and aerosols that cannot be used and are generated during production processes with volumetric activity exceeding the permissible average annual volumetric activity (ARV) given in Appendix P-2 of NRB-99.

Liquid and solid radioactive waste are divided according to specific activity into 3 categories: low-level, intermediate-level and high-level (Table 26).

Table26 – Classification of liquid and solid radioactive waste (OSPORB-99)

	Specific activity, kBq/kg
	beta emitting	alpha emitting	transuranic
Low activity
Moderately active	from 10 3 to 10 7	from 10 2 to 10 6	from 10 1 to 10 5
Highly active

Radioactive waste is generated:

− in the process of mining and processing radioactive minerals
new raw materials;

− during the operation of nuclear power plants;

− during the operation and dismantling of ships with nuclear
installations;

− during reprocessing of spent nuclear fuel;

− in the production of nuclear weapons;

− when conducting scientific work using research
Tel nuclear reactors and fissile material;

− when using radioisotopes in industry, copper
medicine, science;

− during underground nuclear explosions.

The management system for solid and liquid radioactive waste at the places of their generation is determined by the project for each organization planning to work with open sources of radiation, and includes their collection, sorting, packaging, temporary storage, conditioning (concentration, solidification, pressing, combustion), transportation, long-term storage and burial.

To collect radioactive waste, organizations must have special collections. The locations of collections must be provided with protective devices to reduce radiation outside their boundaries to an acceptable level.

For temporary storage of radioactive waste that creates a gamma radiation dose of more than 2 mGy/h at the surface, special protective wells or niches must be used.

Liquid radioactive waste is collected in special containers and then sent for disposal. It is prohibited to discharge liquid radioactive waste into domestic and storm sewers, reservoirs, wells, boreholes, irrigation fields, filtration fields and onto the Earth's surface.

During nuclear reactions occurring in the reactor core, radioactive gases are released: xenon-133 (T physical = 5 days), krypton-85 (T physical = 10 years), radon-222 (T physical = 3.8 day) and others. These gases enter the adsorber filter, where they lose their activity and only then are released into the atmosphere. Some carbon-14 and tritium are also released into the environment.

Another source of rhodium nuclides entering the environment from operating nuclear power plants is unbalanced and process water. Fuel rods located in the reactor core are often deformed and fission products enter the coolant. An additional source of radiation in the coolant are radionuclides formed as a result of irradiation of reactor materials with neutrons. Therefore, the primary circuit water is periodically renewed and cleared of radionuclides.

To prevent environmental pollution, water from all technological circuits of the nuclear power plant is included in the circulating water supply system (Fig. 8).

Nevertheless, part of the liquid waste is discharged into a cooling pond available at each nuclear power plant. This reservoir is a low-flow basin (most often it is an artificial reservoir), so the discharge of liquids containing even small amounts of radionuclides into it can lead to dangerous concentrations. Discharge of liquid radioactive waste into cooling ponds is strictly prohibited by the Sanitary Rules. Only liquids in which the concentration of radioisotopes does not exceed permissible limits can be sent into them. In addition, the amount of liquids discharged into a reservoir is limited by the permissible discharge norm. This standard is established in such a way that the impact of radionuclides on water users does not exceed a dose of 5´10 -5 Sv/year. Volumetric activity of the main radionuclides in discharged water from nuclear power plants in the European part of Russia, according to Yu.A. Egorova (2000), is (Bq):

Rice. 8. Block diagram of NPP water supply recycling

In progress self-cleaning water, these radionuclides sink to the bottom and are gradually buried in bottom sediments, where their concentration can reach 60 Bq/kg. Relative distribution of radionuclides in the ecosystems of NPP cooling ponds, according to Yu.A. Egorov is given in Table 27. According to this author, such reservoirs can be used for any national economic and recreational purposes.

Table 27 – Relative distribution of radionuclides in cooling ponds, %

Ecosystem components
Hydrobionts: shellfish
filamentous algae
higher plants
Bottom sediments

Do nuclear power plants harm the environment? The operating experience of domestic nuclear power plants has shown that with proper maintenance and well-established environmental monitoring, they are practically safe. The radioactive impact on the biosphere of these enterprises does not exceed 2% of the local radiation background. Landscape-geochemical studies in the ten-kilometer zone of the Beloyarsk NPP show that the density of plutonium contamination in soils of forest and meadow biocenoses does not exceed 160 Bq/m2 and is within the global background (Pavletskaya, 1967). Calculations show that thermal power plants are much more dangerous in terms of radiation, since the coal, peat and gas burned in them contain natural radionuclides of the uranium and thorium families. Average individual radiation doses in the area where thermal power plants with a capacity of 1 GW/year are located range from 6 to 60 μSv/year, and from nuclear power plant emissions – from 0.004 to 0.13 μSv/year. Thus, nuclear power plants during normal operation are more environmentally friendly than thermal power plants.

The danger of nuclear power plants lies only in emergency releases of radionuclides and their subsequent spread in the external environment by atmospheric, water, biological and mechanical routes. In this case, damage is caused to the biosphere, disabling vast areas that cannot be used for economic activity for many years.

Thus, in 1986, at the Chernobyl nuclear power plant, as a result of a thermal explosion, up to 10% of nuclear material was released into the environment,
located in the reactor core.

Over the entire period of operation of nuclear power plants, about 150 emergency cases of radionuclide releases into the biosphere have been officially recorded in the world. This is an impressive figure, showing that the reserve for improving the safety of nuclear reactors is still very large. Therefore, environmental monitoring in the areas of nuclear power plants is very important, which plays a decisive role in developing methods for localizing radioactive contamination and their elimination. A special role here belongs to scientific research in the field of studying geochemical barriers at which radioactive elements lose their mobility and begin to concentrate.

Radioactive waste containing radionuclides with a half-life of less than 15 days is collected separately and kept in temporary storage areas to reduce activity to safe levels, after which it is disposed of as normal industrial waste.

The transfer of radioactive waste from the organization for processing or disposal must be carried out in special containers.

Processing, long-term storage and disposal of radioactive waste are carried out by specialized organizations. In some cases, it is possible to carry out all stages of radioactive waste management in one organization, if this is provided for by the project or if a special permit has been issued from state supervisory authorities.

The effective radiation dose to the population caused by radioactive waste, including the storage and disposal stages, should not exceed 10 μSv/year.

The largest volume of radioactive waste is supplied by nuclear power plants. Liquid radioactive waste from nuclear power plants is the bottoms of evaporators, slurry from mechanical and ion exchange filters for purifying loop water. At nuclear power plants they are stored in concrete tanks lined with stainless steel. Then they are cured and buried using special technology. Solid waste from nuclear power plants includes failed equipment and its parts, as well as spent materials. As a rule, they have low activity and are disposed of at nuclear power plants. Waste with medium and high activity is sent for disposal in special underground storage facilities.

Radioactive waste storage facilities are located deep underground (at least 300 m), and they are constantly monitored, since radionuclides emit a large amount of heat. Underground storage facilities for radioactive waste must be long-term, designed for hundreds and thousands of years. They are located in seismically quiet areas, in homogeneous rock masses devoid of cracks. The most suitable for this are granite geological complexes of mountain ranges adjacent to the ocean coast. It is most convenient to construct underground tunnels for radioactive waste in them (Kedrovsky, Chesnokov, 2000). Reliable radioactive waste storage facilities can be located in permafrost. One of them is planned to be created on Novaya Zemlya.

To facilitate disposal and ensure reliability of the latter, liquid highly active radioactive waste is converted into solid inert substances. Currently, the main methods for processing liquid radioactive waste are cementation and vitrification, followed by enclosure in steel containers that are stored underground at a depth of several hundred meters.

Researchers from the Moscow Radon Association proposed a method for converting liquid radioactive waste into stable aluminosilicate ceramics at a temperature of 900°C using carbamide (urea), fluorine salts and natural aluminosilicates (Lashchenova, Lifanov, Solovyov, 1999).

However, for all their progressiveness, the listed methods have a significant drawback - the volume of radioactive waste is not reduced. Therefore, scientists are constantly looking for other methods of disposing of liquid radioactive waste. One of these methods is selective sorption of radionuclides. As sorbents researchers propose using natural zeolites, with the help of which liquids can be purified from radioisotopes of cesium, cobalt and manganese to safe concentrations. At the same time, the volume of the radioactive product is reduced tens of times (Savkin, Dmitriev, Lifanov et al., 1999). Yu.V. Ostrovsky, G.M. Zubarev, A.A. Shpak and other Novosibirsk scientists (1999) proposed galvanochemical
processing of liquid radioactive waste.

A promising method for disposing of high-level waste is to remove it into space. The method was proposed by academician A.P. Kapitsa in 1959. Intensive research is currently underway in this area.

Radioactive waste is produced in large quantities by nuclear power plants, research reactors and the military sphere (nuclear reactors of ships and submarines).

According to the IAEA, by the end of 2000, 200 thousand tons of irradiated fuel were unloaded from nuclear reactors.

It is assumed that the main part of it will be removed without processing (Canada, Finland, Spain, Sweden, USA), the other part will be processed (Argentina, Belgium, China, France, Italy, Russia, Switzerland, England, Germany).

Belgium, France, Japan, Switzerland, England bury blocks of radioactive waste encased in borosilicate glass.

Burial at the bottom of seas and oceans. Disposal of radioactive waste in seas and oceans has been practiced by many countries. The United States was the first to do this in 1946, then Great Britain in 1949, Japan in 1955, and the Netherlands in 1965. The first marine repository for liquid radioactive waste appeared in the USSR no later than 1964.

In the sea dumps of the North Atlantic, where, according to the IAEA, from 1946 to 1982, 12 countries of the world flooded radioactive waste with a total activity of more than MCi (one megaCurie). Regions of the globe according to the amount of total activity are now distributed as follows:

a) North Atlantic - approximately 430 kCi;

b) the seas of the Far East - about 529 kCi;

c) Arctic - does not exceed 700 kCi.

25-30 years have passed since the first flooding of high-level waste in the Kara Sea. Over the years, the activity of reactors and spent fuel has naturally decreased many times. Today in the northern seas the total activity of radioactive waste is 115 kCi.

At the same time, we must assume that the marine disposal of radioactive waste was carried out by competent people - professionals in their field. RW was flooded in the depressions of bays, where currents and underwater waters do not affect these deep layers. Therefore, the radioactive waste “sits” there and does not spread anywhere, but is only absorbed by special precipitation.

It should also be taken into account that radioactive waste with the highest activity is preserved with hardening mixtures. But even if radionuclides get into sea water, they are sorbed by these sediments in the immediate vicinity of the flooding site. This was confirmed by direct measurements of the radiation situation.

The most frequently discussed option for disposal of radioactive waste is the use of disposal in a deep basin, where the average depth is at least 5 km. The deep rocky ocean floor is covered with a layer of sediment, and shallow burial under tens of meters of sediment can be obtained by simply throwing the container overboard. Deep burial under hundreds of meters of sediment will require drilling and backfilling. The deposits are saturated with seawater, which after tens or hundreds of years can corrode (through corrosion) the fuel cell canisters of used fuel. However, it is assumed that the sediments themselves adsorb leached fission products, preventing them from entering the ocean. Calculations of the consequences of the extreme case of destruction of the container shell immediately after entering a layer of sediments showed that dispersion of a fuel element containing fission products under a layer of sediments will occur no earlier than in 100-200 years. By then, the level of radioactivity will have dropped by several orders of magnitude.

Final burial in salt deposits. Salt deposits are attractive sites for long-term disposal of radioactive waste. The fact that salt is found in solid form in a geological layer indicates that there has been no circulation of groundwater since its formation several hundred million years ago. Thus, fuel placed in such a deposit will not be subject to leaching by soil
waters. This type of salt deposits is very common.

Geological burial. Geological disposal involves placing containers containing spent fuel elements in a stable formation, usually at a depth of 1 km. It can be assumed that such rocks contain water, since their depth is significantly lower than the groundwater table. However, water is not expected to play a major role in heat transfer from the containers, so storage should be designed to keep the surface temperature of the canisters no more than 100°C or so. However, the presence of groundwater means that material leached from stored blocks can penetrate the water reservoir. This is an important issue when designing such systems. The circulation of water through rock as a result of density differences caused by temperature gradients over long periods of time is important in determining the migration of fission products. This process is very slow and therefore is not expected to cause major problems. However, for long-term disposal systems it must be taken into account.

The choice between different disposal methods will be determined by the availability of suitable sites, and much more biological and oceanographic data will be required. However, research in many countries shows that used fuel can be treated and disposed of without undue risk to humans and the environment.

Recently, the possibility of throwing containers with long-lived isotopes using rockets onto the invisible far side of the Moon has been seriously discussed. But how can we ensure a 100% guarantee that all launches will be successful and that none of the launch vehicles will explode in the earth’s atmosphere and cover it with deadly ash? No matter what the rocket scientists say, the risk is very high. And in general, we don’t know why our descendants will need the far side of the Moon. It would be extremely frivolous to turn it into a deadly radiation dump.

Disposal of plutonium. In the fall of 1996, the International Scientific Seminar on Plutonium was held in Moscow. This extremely toxic substance comes from a nuclear reactor and was previously used to produce nuclear weapons. But over the years of using nuclear energy, thousands of tons of plutonium have already accumulated on Earth; no country needs so much to produce weapons. So the question arose, what to do with it next?

Just leaving it somewhere in storage is a very expensive pleasure.

As is known, plutonium does not occur in nature; it is obtained artificially from uranium-238 by irradiating the latter with neutrons in a nuclear reactor:

92 U 238 + 0 n 1 -> -1 e 0 + 93 Pu 239 .

Plutonium has 14 isotopes with mass numbers from 232 to 246; The most common isotope is 239 Pu.

Plutonium released from spent fuel from nuclear power plants contains a mixture of highly active isotopes. Under the influence of thermal neutrons, only Pu-239 and Pu-241 fission, and fast neutrons cause the fission of all isotopes.

The half-life of 239 Pu is 24,000 years, 241 Pu is 75 years, and the isotope 241 Am is formed with strong gamma radiation. The toxicity is such that a thousandth of a gram is fatal.

Academician Yu. Trutnev proposed storing plutonium in underground storage facilities constructed using nuclear explosions. Radioactive waste, together with rocks, vitrifies and does not spread into the environment.

The position that spent nuclear fuel (SNF) is the most valuable means for the nuclear industry, subject to processing and use in a closed cycle: uranium - reactor - plutonium - reprocessing - reactor (England, Russia, France) is considered promising.

In 2000, Russian nuclear power plants accumulated about 74,000 m 3 of liquid radioactive waste with a total activity of 0.22´10 5 Ci, about 93,500 m 3 of solid radioactive waste with an activity of 0.77´10 3 Ci and about 9,000 tons of spent nuclear fuel with an activity of over 4´10 9 Ki. At many nuclear power plants, radioactive waste storage facilities are 75% full and the remaining volume will only last for 5-7 years.

Not a single nuclear power plant is equipped with equipment for conditioning the generated radioactive waste. According to experts from the Ministry of Atomic Energy of Russia, in reality, in the next 30-50 years, radioactive waste will be stored on the territory of nuclear power plants, so there is a need to create special long-term storage facilities there, adapted for the subsequent extraction of radioactive waste from them for transportation to the final disposal site.

Liquid radioactive waste from the Navy is stored in onshore and floating tanks in regions where nuclear-powered ships are based. The annual supply of such radioactive waste is about 1300 m3. They are processed by two technical transport vessels (one in the Northern Fleet, the other in the Pacific Fleet).

In addition, due to the intensification of the use of ionizing radiation in human economic activity, the volume of spent radioactive sources coming from enterprises and institutions that use radioisotopes in their work is increasing every year. Most of these enterprises are located in Moscow (about 1000), regional and republican centers.

This category of radioactive waste is disposed of through the centralized system of territorial special plants "Radon" of the Russian Federation, which receive, transport, process and dispose of spent sources of ionizing radiation. The Department of Housing and Communal Services of the Ministry of Construction of the Russian Federation is responsible for 16 special plants "Radon": Leningrad, Nizhny Novgorod, Samara, Saratov, Volgograd, Rostov, Kazan, Bashkir, Chelyabinsk, Yekaterinburg, Novosibirsk, Irkutsk, Khabarovsk, Primorsky, Murmansk, Krasnoyarsk. The seventeenth special plant, Moskovsky (located near Sergiev Posad), is subordinate to the Moscow Government.

Each Radon enterprise has specially equipped radioactive waste disposal sites(PZRO).

To bury spent sources of ionizing radiation, engineered near-surface well-type storage facilities are used. Each Radon enterprise has a normal
operation of storage facilities, accounting of buried waste, constant radiation control and monitoring of the radioecological state of the environment. Based on the results of monitoring the radioecological situation in the area where the RWDF is located, a radioecological passport of the enterprise is periodically compiled, which is approved by the control and supervisory authorities.

Radon special plants were designed in the 70s of the 20th century in accordance with the requirements of now outdated radiation safety standards.

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Removal, processing and disposal of waste from hazard classes 1 to 5

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In the 20th century, the non-stop search for an ideal energy source seemed to have ended. This source was the nuclei of atoms and the reactions occurring in them - the active development of nuclear weapons and the construction of nuclear power plants began all over the world.

But the planet quickly faced the problem of processing and destroying nuclear waste. The energy from nuclear reactors carries a lot of dangers, as does the waste from this industry. Until now, there is no thoroughly developed processing technology, while the field itself is actively developing. Therefore, safety depends primarily on proper disposal.

Definition

Nuclear waste contains radioactive isotopes of certain chemical elements. In Russia, according to the definition given in Federal Law No. 170 “On the Use of Atomic Energy” (dated November 21, 1995), the further use of such waste is not provided for.

The main danger of materials is the emission of gigantic doses of radiation, which has a detrimental effect on a living organism. The consequences of radioactive exposure include genetic disorders, radiation sickness and death.

Classification map

The main source of nuclear materials in Russia is the nuclear energy sector and military developments. All nuclear waste has three degrees of radiation, familiar to many from physics courses:

• Alpha - radiating.
• Beta - emitting.
• Gamma - radiating.

The first are considered the most harmless, as they produce a non-hazardous level of radiation, unlike the other two. True, this does not prevent them from being included in the class of the most hazardous waste.


In general, the map of classifications of nuclear waste in Russia divides it into three types:

1. Solid nuclear debris. This includes a huge amount of maintenance materials in the energy sector, personnel clothing, and garbage that accumulates during work. Such waste is burned in furnaces, after which the ashes are mixed with a special cement mixture. It is poured into barrels, sealed and sent to storage. The burial is described in detail below.
2. Liquid. The operation of nuclear reactors is impossible without the use of technological solutions. In addition, this includes water that is used to treat special suits and wash workers. The liquids are thoroughly evaporated, and then burial occurs. Liquid waste is often recycled and used as fuel for nuclear reactors.
3. Elements of the design of reactors, transport and technical control equipment at the enterprise form a separate group. Their disposal is the most expensive. Today, there are two options: installing the sarcophagus or dismantling it with its partial decontamination and further sending it to storage for burial.

The map of nuclear waste in Russia also identifies low-level and high-level:

• Low-level waste - arises during the activities of medical institutions, institutes and research centers. Here radioactive substances are used to carry out chemical tests. The level of radiation emitted by these materials is very low. Proper disposal can turn hazardous waste into normal waste in about a few weeks, after which it can be disposed of as regular waste.
• High-level waste is spent reactor fuel and materials used in the military industry to develop nuclear weapons. The fuel at the stations consists of special rods containing a radioactive substance. The reactor operates for approximately 12 - 18 months, after which the fuel must be changed. The volume of waste is simply colossal. And this figure is growing in all countries developing the nuclear energy sector. Disposal of high-level waste must take into account all the nuances in order to avoid disaster for the environment and humans.

Recycling and disposal

At the moment, there are several methods for disposing of nuclear waste. All of them have their advantages and disadvantages, but no matter how you look at them, they do not allow you to completely get rid of the danger of radioactive exposure.

Burial

Waste disposal is the most promising disposal method, which is especially actively used in Russia. First, the process of vitrification or “vitrification” of the waste occurs. The spent substance is calcined, after which quartz is added to the mixture, and this “liquid glass” is poured into special cylindrical steel molds. The resulting glass material is resistant to water, which reduces the possibility of radioactive elements entering the environment.

The finished cylinders are brewed and washed thoroughly, getting rid of the slightest contamination. Then they are sent to storage for a very long time. The storage facility is located in geologically stable areas so that the storage facility is not damaged.

Geological disposal is carried out at a depth of more than 300 meters in such a way that the waste does not require further maintenance for a long time.

Burning

Some nuclear materials, as mentioned above, are direct results of production, and a kind of by-product waste in the energy sector. These are materials that were exposed to irradiation during production: waste paper, wood, clothing, household waste.

All this is burned in specially designed furnaces that minimize the level of toxic substances into the atmosphere. The ash, among other wastes, is cemented.

Cementing

Disposal (one of the methods) of nuclear waste in Russia by cementing is one of the most common practices. The idea is to place irradiated materials and radioactive elements in special containers, which are then filled with a special solution. The composition of such a solution includes a whole cocktail of chemical elements.

As a result, it is practically not exposed to the external environment, which allows it to achieve an almost unlimited lifespan. But it is worth making a reservation that such burial is possible only for the disposal of waste of medium hazard level.

Seal

A long-standing and fairly reliable practice aimed at disposal and reduction of waste volume. It is not used for processing basic fuel materials, but can process other low-hazard wastes. This technology uses hydraulic and pneumatic presses with low pressure force.

Reuse

The use of radioactive material in the field of energy does not occur to its full extent due to the specific activity of these substances. Having spent its time, the waste still remains a potential source of energy for reactors.

In the modern world, and especially in Russia, the situation with energy resources is quite serious, and therefore the secondary use of nuclear materials as fuel for reactors no longer seems incredible.

Today, there are methods that make it possible to use spent raw materials for energy applications. Radioisotopes contained in waste are used for food processing and as a “battery” to operate thermoelectric reactors.

But the technology is still in development, and an ideal processing method has not been found. However, the processing and destruction of nuclear waste can partially resolve the issue with such waste by using it as fuel for reactors.

Unfortunately, in Russia, such a method of getting rid of nuclear waste is practically not being developed.

Volumes

In Russia, throughout the world, the volume of nuclear waste sent for disposal amounts to tens of thousands of cubic meters annually. Every year, European storage facilities accept about 45 thousand cubic meters of waste, while in the United States only one landfill in the state of Nevada absorbs this volume.

Nuclear waste and work related to it abroad and in Russia are the activities of specialized enterprises equipped with high-quality technology and equipment. At enterprises, waste is subjected to various processing methods described above. As a result, it is possible to reduce the volume, reduce the level of danger, and even use some waste in the energy sector as fuel for nuclear reactors.

The peaceful atom has long proven that everything is not so simple. The energy sector is developing and will continue to develop. The same can be said about the military sphere. But if we sometimes turn a blind eye to the emission of other waste, improperly disposed nuclear waste can cause a total catastrophe for all of humanity. Therefore, this issue requires an early solution before it is too late.

Any production leaves behind waste. And spheres that use the properties of radioactivity are no exception. Free circulation of nuclear waste is, as a rule, unacceptable even at the legislative level. Accordingly, they must be isolated and preserved, taking into account the characteristics of the individual elements.

A sign that is a warning about the danger of ionizing radiation from RW (radioactive waste)

Radioactive waste (RAW) is a substance that contains elements that are radioactive. Such waste has no practical significance, that is, it is unsuitable for recycling.

Note! Quite often the synonymous concept is used -.

It is worth distinguishing from the term “radioactive waste” the concept “spent nuclear fuel - SNF”. The difference between spent nuclear fuel and radioactive waste is that spent nuclear fuel, after proper reprocessing, can be reused as fresh materials for nuclear reactors.

Additional information: SNF is a collection of fuel elements, mainly consisting of fuel residues from nuclear installations and a large number of half-life products, as a rule, these are the isotopes 137 Cs and 90 Sr. They are actively used in scientific and medical institutions, as well as in industrial and agricultural enterprises.

In our country there is only one organization that has the right to carry out activities for the final disposal of radioactive waste. This is the National Operator for Radioactive Waste Management (FSUE NO RAO).

The actions of this organization are regulated by the Legislation of the Russian Federation (No. 190 Federal Law of July 11, 2011). The law prescribes the mandatory disposal of radioactive waste produced in Russia and also prohibits its import from abroad.

Classification

The classification of the type of waste under consideration includes several classes of radioactive waste and consists of:

• low-level (they can be divided into classes: A, B, C and GTCC (the most dangerous));
• intermediate-level (in the United States this type of radioactive waste is not classified as a separate class, so the concept is usually used in European countries);
• highly active radioactive waste.

Sometimes another class of radioactive waste is distinguished: transuranium. This class includes waste characterized by the content of transuranic α-emitting radionuclides with long decay periods and extremely high concentrations. Due to the long half-life of this waste, burial occurs much more thoroughly than the isolation of low-level and intermediate-level radioactive waste. It is extremely problematic to predict how dangerous these substances will be for the environment and the human body.

The problem of radioactive waste management

During the operation of the first enterprises using radioactive compounds, it was generally accepted that the dispersion of a certain amount of radioactive waste in environmental areas was acceptable, in contrast to the waste generated in other industrial sectors.

Thus, at the notorious Mayak enterprise, at the initial stage of its activities, all radioactive waste was discharged into the nearest water sources. Thus, serious pollution of the Techa River and a number of reservoirs located on it occurred.

Subsequently, it became clear that accumulation and concentration of hazardous radioactive waste occurs in various areas of the biosphere and therefore simply discharging them into the environment is unacceptable. Together with contaminated food, radioactive elements enter the human body, which leads to a significant increase in the risk of radiation exposure. Therefore, in recent years, various methods for collecting, transporting and storing radioactive waste have been actively developed.

Disposal and recycling

Disposal of radioactive waste can occur in different ways. This depends on the class of radioactive waste to which they belong. The most primitive is the recycling of low-level and intermediate-level radioactive waste. We also note that, based on their structure, radioactive waste is divided into short-lived substances with a short half-life and waste with a long half-life. The latter belong to the long-lived class.

For short-lived waste, the simplest method of disposal is their short-term storage in specially designated areas in sealed containers. Over a certain period of time, radioactive waste is neutralized, after which radioactively harmless waste can be processed in the same way as household waste is processed. Such waste may include, for example, materials from medical institutions (HCI). A standard two-hundred-liter barrel made of metal can serve as a container for short-term storage. To avoid the penetration of radioactive elements from the container into the environment, the waste is usually filled with a bitumen or cement mixture.

The photo shows radioactive waste management technologies at one of the modern enterprises in Russia

Disposal of waste constantly generated at nuclear power plants is much more difficult to implement and requires the use of special methods, such as, for example, plasma processing, recently implemented at the Novovoronezh NPP. In this case, radioactive waste is converted into glass-like substances, which are subsequently placed in containers for permanent disposal.

Such processing is absolutely safe and allows reducing the amount of radioactive waste several times. This is facilitated by multi-stage purification of combustion products. The process can run autonomously for 720 hours, with a productivity of up to 250 kg of waste per hour. The temperature in the furnace installation reaches 1800 0 C. It is believed that such a new complex will operate for another 30 years.

The advantages of the plasma RW recycling process over others, as they say, are obvious. Thus, there is no need to carefully sort waste. In addition, numerous cleaning methods can reduce the release of gaseous impurities into the atmosphere.

Radioactive contamination, radioactive waste repositories in Russia

For many years, Mayak, located in northeastern Russia, was a nuclear power plant, but in 1957 it suffered one of the world's most catastrophic nuclear accidents. As a result of the incident, up to 100 tons of hazardous radioactive waste were released into the natural environment, affecting vast areas. At the same time, the disaster was carefully hidden until the 1980s. For many years, waste from the station and from the contaminated surrounding area was dumped into the Karachay River. This caused contamination of a water source that was so necessary for thousands of people.

“Mayak” is far from the only place in our country susceptible to radioactive contamination. One of the main environmentally hazardous facilities in the Nizhny Novgorod region is the radioactive waste disposal site, located 17 kilometers from the city of Semenov, also widely known as the Semenovsky burial ground.

There is a storage facility in Siberia that has been storing nuclear waste for more than 40 years. To store radioactive materials, they use unclosed pools and containers, which already contain approximately 125 thousand tons of waste.

In Russia, a huge number of territories with radiation levels exceeding permissible standards have been discovered. These even include such large cities as St. Petersburg, Moscow, Kaliningrad, etc. For example, in a kindergarten near the Institute. Kurchatov in our capital, a sandbox for children with a radiation level of 612 thousand mR/hour was discovered. If a person had been at this “safe” children’s facility for 1 day, he would have been exposed to a lethal dose of radiation.

During the existence of the USSR, especially in the middle of the last century, the most dangerous radioactive waste could be dumped into nearby ravines, so that a whole landfill was formed. And with the expansion of cities, new sleeping and industrial neighborhoods were built in these contaminated places.

Assessing the fate of radioactive waste in the biosphere is quite problematic. Rain and winds actively spread pollution throughout all surrounding areas. Thus, in recent years, the rate at which the White Sea is polluted as a result of radioactive waste disposal has increased significantly.

Disposal problems

Today, there are two approaches to the implementation of storage and disposal processes for nuclear waste: local and regional. Disposal of radioactive waste at the site of their production is very convenient from various points of view, however, this approach can lead to an increase in the number of hazardous disposal sites during the construction of new structures. On the other hand, if the number of these places is strictly limited, then the problem of cost and ensuring safe transportation of waste will arise. Indeed, regardless of whether the transportation of radioactive waste is a production process, it is worth excluding non-existent danger criteria. It is quite difficult, if not impossible, to make an uncompromising choice in this matter. In different states this issue is resolved differently and there is no consensus yet.

One of the main problems can be considered the identification of geological formations suitable for organizing a radioactive waste cemetery. Deep adits and mines used for the extraction of rock salt are best suited for this purpose. Wells are also often used in areas rich in clay and rock. High water resistance, one way or another, is one of the most important characteristics when choosing a burial site. A kind of radioactive waste repository appears in places of underground nuclear explosions. Thus, in the state of Nevada, USA, at a site that served as a testing ground for approximately 450 explosions, almost each of these explosions formed a repository of high-level nuclear waste buried in rock without any technical “obstacles.”

Thus, the problem of the formation of radioactive waste is extremely difficult and controversial. Advances in nuclear energy, of course, bring enormous benefits to humanity, but at the same time they create a lot of troubles. And one of the main and unresolved problems today is the problem of radioactive waste disposal.

More details about the history of the issue, as well as about the modern view of the problem of nuclear waste, can be seen in the special edition of the “Nuclear Heritage” program of the “Science 2.0” TV channel.