Radiation waste and their classification. Radioactive waste. Sources of appearance. Classification. Sources of hazardous waste

IN modern world the problem of disposal of radioactive waste is on a par with others environmental issues... With an increase in the population and the development of technological progress, the amount of such waste is constantly increasing. Meanwhile, their correct collection, storage and subsequent disposal is a complex and time-consuming process.

What is the danger of radioactive substances?

The danger of such materials can hardly be overestimated. Each territory has its own radiation background, which is considered normal for it. If released into the air, land or water, this type of waste increases the local radiation background. Harmful substances enter the organisms of animals and people, provoking the development of mutations and poisoning, increasing the mortality rate among the population.

Given the danger of such materials, today the legislator obliges enterprises that use radioactive raw materials to establish special filters reducing pollution the environment... Despite this, the amount of harmful elements is constantly increasing. The degree of radiation hazard directly depends on the following factors:

• the size of the population living in the hazardous area;
• territory that has been contaminated (area, nature);
• dose rates;
• the amount of waste contained in the biosphere.

After entering the human body, harmful substances can lead to the development of serious diseases, which are characterized by a high mortality rate. Preventing the movement of such substances along the food chain is an important task. If unsuccessful, they will spread out of control.

Sources of hazardous waste

Radioactive waste is a substance that is dangerous to the environment and is useless for further production. Disposal of radioactive waste should be carried out according to special rules, separately from other types of used substances.

There are several types of classification of such waste. They can have a variety of physical forms and chemical characteristics. Differences also lie in the concentration of substances and the half-lives of their main elements. Today, radioactive waste occurs due to:

• creation of fuel intended for operation of nuclear reactors;
• operation of nuclear reactors;
• treatment of fuel with radiation;
• recycling scintillation counters;
• reprocessing of previously used fuel;
• functioning of ventilation systems (if the enterprise uses radioactive substances, they will be emitted by the ventilation system in the form of gas).

Sources can also be used medical devices, dishes that were in special laboratories, glass containers into which fuel was poured. We must also not forget about the existence of PIR - natural sources of radiation that can pollute the surrounding territories.

Classification

There are several signs by which radioactive substances are separated. For example, they may or may not contain nuclear-type elements. They also isolate materials that were formed as a result of the extraction of uranium ores, and substances that are not in any way related to nuclear energy.

Depending on the condition, there are three forms of hazardous materials:

• solid. This includes glassware used in hospitals and special research laboratories;
• liquid. Formed as a result of the processing of previously used fuel. The activity of such substances is usually quite high, so they can cause significant harm to the environment;
• gaseous. This group of substances includes materials released by ventilation systems of enterprises engaged in the processing of radioactive raw materials.

Depending on the radioactivity of the waste, they are divided into:

• highly active;
• medium active;
• low activity.

The most dangerous is the group of high-level waste, the least hazardous is the low-level waste. The half-life is also important. This indicator reflects the time during which half of the atoms contained in a radioactive substance decay. The higher the number, the faster the waste disintegrates. This reduces the time it takes for the substance to lose its negative properties, but up to that moment more energy is released.

RW storage

RW storage means the collection of hazardous elements with their subsequent transfer to processing or disposal facilities. This is a temporary measure that allows you to concentrate radioactive waste in one place, and then deliver them to another. Disposal means permanent placement of radioactive waste in special repositories where it will not harm the environment.

In some cases, enterprises that generate such substances prefer to store them on their territory until they are completely decontaminated. This is possible only if the half-life of the elements does not exceed several decades. In other cases, burial grounds are used.

It should be noted that substances that will pose a threat to the environment for no more than five hundred years come to the burial grounds. This circumstance is explained by the fact that the stored material must become safe before the place of its storage collapses. Certain requirements are also put forward to the containers in which the material will be stored. So:

• only solids or materials that have hardened as a result of processing can be stored in this way;
• the container must be completely sealed. It is necessary to exclude the possibility of the least exit of material from the container;
• the container must maintain its characteristics at temperatures from fifty (minus) to seventy (plus) degrees. During the draining of substances with high temperature, the container must withstand heating up to one hundred and thirty degrees;
• strength is a prerequisite. The container must be able to withstand the impact of physical forces on it (for example, remain unharmed after an earthquake).

During storage of waste, their isolation and facilitation of further procedures that will be carried out in the process of subsequent stages of burial / processing should be ensured. The state or legal entity providing storage must monitor the containers and monitor the environment.

Recycling

Today there are different ways of processing and further utilization of radioactive waste. Their use depends on the specific substance and its activity. Depending on several parameters, the following can be applied:

• vitrification. Processing of radioactive waste is carried out using borosilicate glass. It has a stable shape, due to which radioactive elements in such material will be safely stored for several thousand years;
• burning. The method can be used for limited volume reduction of emitting materials. Since the air can be polluted during their combustion, the method can be used to dispose of contaminated waste paper, wood, clothing, rubber. The special design of the furnaces avoids the excessive release of hazardous materials into the air;
• seal. It is used when it is necessary to dispose of large items. Pressing allows the material to be compacted, reducing its final size;
• cementing. Waste is placed in a special container, after which the latter is filled with a large amount of cement, created with a selection of special chemicals.

Despite the fact that such methods are used quite actively today, they do not solve the problem complete elimination waste. Hazardous materials still have the potential to affect the environment. In this regard, today, new methods of disposal are being developed (for example, burial in the Sun).

RW processing depending on their activity

The methods described above are used for the disposal of a variety of radioactive substances. An important role in the choice of a specific method is played by such an indicator as the activity of radioactive waste. So:

• low-level waste is the easiest to dispose of. They become safe within just a few years. For their storage, it is enough to use special sealed containers. After the danger has disappeared, they can be disposed of in the usual way;
• intermediate level waste is decontaminated much longer (several times). For their storage, special barrels made of several alloys are used. After filling, they are filled with cement and bitumen in several layers;
• high-level waste is the most hazardous. They remain a threat to the environment for centuries. Therefore, before the disposal of such waste (in most cases, this is the fuel used at nuclear power plants), the plants recycle them. The procedure allows most of the fuel to be reused. The useless residue is poured over with glass (vitrification) and stored in deep wells that are in the rock.

High-level waste in some cases can remain hazardous for millennia. And although the number of reservoirs with them is relatively small, in the future they can become a serious problem for humanity.

Thus, radioactive waste is a danger to both the environment and humanity. Therefore, they must be disposed of in a special way. Today radioactive waste is classified according to different parameters. The most dangerous are highly active substances. Their utilization provides for vitrification followed by placement in deep rocky wells. Since all existing on this moment the methods do not allow to completely get rid of hazardous materials; today, work is underway to find new methods for RW disposal.

Radioactive waste

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

According to the Russian "Law on the use of atomic energy"(Dated November 21, 1995 No. 170-FZ) radioactive waste (RW) is nuclear materials and radioactive substances, the further use of which is not envisaged. Under Russian law, the import of radioactive waste into the country is prohibited.

Radioactive waste and spent nuclear fuel are often confused and considered synonymous. You should distinguish between these concepts. Radioactive waste is material that is not intended to be used. Spent nuclear fuel is a fuel element containing nuclear fuel residues and many fission products, mainly 137 Cs and 90 Sr, which are widely used in industry, agriculture, medicine and scientific activities. Therefore, it is a valuable resource, which is processed to obtain fresh nuclear fuel and isotopic sources.

Waste sources

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 discharges from installations where radioactive materials are processed;
• in liquid form, ranging from solutions of scintillation counters from research facilities to liquid high-level waste generated during the reprocessing of spent fuel;
• in solid form (contaminated consumables, glassware from hospitals, medical research facilities and radiopharmaceutical laboratories, vitrified waste from reprocessing fuel or spent fuel from nuclear power plants when considered waste).

Examples of sources of radioactive waste in human activities:

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

• Coal . Coal contains a small number 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 as they practically do not burn.

However, the radioactivity of ash is also very low, it is approximately equal to the radioactivity of black shale and less than that of phosphate rocks, but it poses a known hazard, since some of the 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

Radioactive waste is conventionally divided into:

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

US legislation also allocates transuranic radioactive waste. This class includes wastes contaminated with alpha-emitting transuranium radionuclides with half-lives of more than 20 years and a concentration of more than 100 nCi / g, regardless of their form or origin, excluding high-level radioactive waste. Due to the long decay period of transuranic waste, their disposal is more thorough than the disposal of low-level and intermediate-level waste. Also, special attention is paid to this class of waste because all transuranic elements are artificial and the behavior in the environment and in the human body of some of them 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).

Heat generation is one of the criteria for this classification. Low-level radioactive waste produces extremely little heat. In the case of moderately active people, it is significant, but active heat removal is not required. The heat release of high-level radioactive waste is so great that they require active cooling.

Radioactive waste management

Initially, it was believed that a sufficient measure is the scattering of radioactive isotopes in the environment, by analogy with production waste in other industries. At the Mayak enterprise in the first years of operation, all radioactive waste was discharged into nearby water bodies. As a result, the Techa cascade of reservoirs and the Techa river itself turned out to be polluted.

Later it turned out that due to natural natural and biological processes radioactive isotopes are concentrated in various subsystems of the biosphere (mainly in animals, in their organs and tissues), which increases the risks of exposure 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 been changed.

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

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

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

4) Protecting future generations... Radioactive waste is managed in such a way that predictable health effects for future generations do not exceed appropriate levels of effects that are acceptable today.

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

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

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

8) Interdependencies of radioactive waste generation and management... Due consideration is given to the interdependencies between all stages of radioactive waste generation and management.

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

The main stages of radioactive waste management

• At storage radioactive waste, they should be contained in such a way that:
  • provided their isolation, protection and monitoring of the environment;
  • actions at subsequent stages were facilitated as much as possible (if any).

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

• Preliminary processing waste is the initial stage of waste management. It includes collection, regulation chemical composition and decontamination and may include an intermediate storage period. This step is very important because in many cases the pretreatment is the best opportunity to separate the waste streams.

• Treatment radioactive waste includes operations whose purpose is to improve safety or economy by changing the characteristics of the radioactive waste. Basic treatment concepts: volume reduction, radionuclide removal and compositional modification. Examples:
  • incineration 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 such operations in which the radioactive waste is formed into a form suitable for movement, transportation, storage and disposal. These operations may include immobilizing radioactive waste, placing waste in containers and providing additional packaging. Common methods of immobilization include solidification of low and intermediate level liquid radioactive waste by incorporation into cement (cementing) or bitumen (bitumenization), as well as vitrification of liquid radioactive waste. Immobilized waste, in turn, depending on the nature and their concentration, can be packed in various containers, ranging from ordinary 200-liter steel drums to those with a complex structure with thick walls. In many cases, processing and conditioning are carried out in close connection with each other.

• Burial mainly consists in placing the radioactive waste in a disposal facility with adequate security, with no intention of removal and without long-term storage monitoring and maintenance. Safety is mainly achieved through concentration and containment, which entails containment of appropriately concentrated radioactive waste in a disposal facility.

Technology

Management of intermediate level radioactive waste

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

Storage

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

Vitrification

Long-term storage of radioactive waste requires conservation of waste in a form that will not react and degrade over a long period of time. One of the ways to achieve this state is vitrification (or vitrification). Currently, in Sellafield (Great Britain), 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 denitrogenate fission products in order to increase the stability of the resulting vitreous mass.

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

After filling, the cylinder is welded, then washed. After being examined for external contamination, the steel cylinders are sent to underground storage facilities. This state of waste has remained unchanged for many thousands of years.

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

In 1997, in 20 countries with for the most part of the world nuclear potential, the stocks of spent fuel in storage facilities inside the reactors amounted to 148 thousand tons, 59% of which were disposed of. The external storage facilities contained 78 thousand tons of waste, of which 44% was utilized. Taking into account the rate of utilization (about 12 thousand tons annually), it is still a long way to the final disposal of waste.

Geological burial

The search for suitable deep final disposal sites is currently under way in several countries; the first such repositories are expected to be operational after 2010. The international research laboratory in Grimsel, Switzerland, deals with issues related to the disposal of radioactive waste. Sweden talks about plans to directly dispose 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, active protests are announced by residents of the village of Gorleben in the Wendland region. Until 1990, this site seemed ideal for disposal of radioactive waste due to its proximity to the borders of the former German Democratic Republic. Now the radioactive waste is in Gorleben for temporary storage, the decision on the place of their final disposal has not yet been made. The US government chose Yucca Mountain, Nevada, for the burial site, but the project has met with strong opposition and has become a topic of heated discussion. There is a project to create an international repository for high-level radioactive waste; Australia and Russia are proposed as possible disposal sites. However, the Australian authorities oppose such a proposal.

There are projects for the disposal of radioactive waste in the oceans, including burial under the abyssal zone of the seabed, burial in the subduction zone, as a result of which the waste will slowly sink to the earth's mantle, as well as burial under a natural or artificial island. These projects have obvious advantages and will allow solving the unpleasant problem of radioactive waste disposal at the international level, but despite this, they are currently frozen due to the prohibitive provisions of the maritime law. Another reason is that in Europe and North America there is a serious fear of 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 prohibitions were strengthened after the disposal of radioactive waste from ships. However, in the future, countries that will not be able to find other solutions to this problem can seriously think about the creation of oceanic storage facilities for radioactive waste.

In the 1990s, several options for conveyor burial of radioactive waste were developed and patented. The technology was supposed to be as follows: a starting well of large diameter up to 1 km deep 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 in the form of a "fireball". After deepening the first "fireball", the second capsule should be lowered into the same well, then the third, etc., creating a kind of conveyor.

Reuse of radioactive waste

Another application for isotopes contained in radioactive waste is their reuse. Already now, 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, since 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 large number of launches and their high cost makes this proposal impractical. The matter is also complicated by the fact that international agreements on this problem have not yet been reached.

Nuclear fuel cycle

Cycle start

Waste from the initial phase of the nuclear fuel cycle is usually waste rock produced from the extraction of uranium and emitting alpha particles. It usually contains radium and its decay products.

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

End of cycle

Substances in which the nuclear fuel cycle has come to an end (mostly spent fuel rods) contain fission products that emit beta and gamma rays. They can also contain alpha-emitting actinides, 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 produced in nuclear reactors.

It is important to distinguish between the processing of uranium for fuel production and the processing of spent 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 capturing neutrons, they stop the chain reaction even when the neutron absorber rods are completely removed.

The fuel that has reached this state must be replaced with fresh fuel, despite the still sufficient amount of uranium-235 and plutonium. Used fuel is currently being sent to storage in the United States. In other countries (in particular, in Russia, Great Britain, France and Japan), this fuel is processed in order to remove fission products, then after re-enrichment it is possible to reuse it. In Russia, such fuel is called regenerated. The reprocessing process includes work with highly radioactive substances, and fission products removed from the fuel are a concentrated form of high-level radioactive waste, just like the chemicals used in reprocessing.

To close the nuclear fuel cycle, it is proposed to use fast reactors, which allows reprocessing fuel that is waste from thermal reactors.

On the issue of nuclear proliferation

When working with uranium and plutonium, the possibility of their use in the creation of nuclear weapons... Active nuclear reactors and nuclear weapons stockpiles are closely guarded. However, high-level radioactive waste from nuclear reactors may contain plutonium. It is identical to the plutonium used in reactors and is composed of 239 Pu (ideal for building nuclear weapons) and 240 Pu (unwanted 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 waste disposal is possible, and after many years the fission products will decay, reducing the radioactivity of the waste and making it easier to work with plutonium. Moreover, the unwanted isotope 240 Pu decays faster than 239 Pu, so the quality of raw materials for weapons increases over time (despite the decrease in quantity). This raises controversy that over time, waste storage may turn into a kind of "plutonium mines", from which it will be relatively easy to extract raw materials for weapons. 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 fraction of 240 Pu in a substance consisting of several isotopes will independently halve - a typical transformation of reactor plutonium into weapons-grade plutonium). Consequently, "weapons-grade plutonium mines", if they become a problem, only in the very distant future.

One solution to this problem is to reuse reprocessed plutonium as fuel, for example, in fast nuclear reactors. However, the very existence of nuclear fuel regeneration factories necessary to separate plutonium from other elements creates an opportunity for the proliferation of nuclear weapons. In pyrometallurgical fast reactors, the resulting waste has an actinoid structure, which makes it impossible to use it to create weapons.

Recycling of nuclear weapons

Waste from the reprocessing of nuclear weapons (as opposed to their manufacture, which requires primary raw materials from reactor fuel), do not contain sources of beta and gamma rays, with the exception of tritium and americium. They contain a much larger number of alpha-emitting actinides, such as plutonium-239, which undergoes a 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 charges in bombs. Plutonium-238 is now an alternative to polonium. For national security reasons, the detailed designs of modern bombs are not covered in the literature available to the general public.

Some models also contain (RTG), which uses plutonium-238 as a durable source of electrical power for the bomb electronics.

It is possible that the fissile material of the old bomb to be replaced will contain the decay products of plutonium isotopes. These include alpha-emitting neptunium-236 from plutonium-240 inclusions, as well as some uranium-235 from plutonium-239. The amount of this waste from the radioactive decay of the bomb nucleus will be very small, 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 is a bigger problem than the decay of plutonium-239 and plutonium-240, since americium is a gamma emitter (its external effect on workers increases) and an alpha emitter, capable of generating heat. Plutonium can be separated from americium different ways, among which are pyrometric treatment and extraction with an aqueous / organic solvent. A modified technology for extracting plutonium from irradiated uranium (PUREX) is also one of the possible separation methods.

In popular culture

In reality, the effect of radioactive waste is described by the effect of ionizing radiation on a substance and depends on its composition (which radioactive elements are included in the composition). Radioactive waste does not acquire any new properties, it does not become more dangerous because it is waste. Their greater danger is explained only by 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 the accident.

see also

Notes (edit)

Links

• Safety in 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)

Radioactive waste (RW) 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 extraction and processing of radioactive ore, during the operation of equipment that generates heat, during the disposal of nuclear waste.

Types and classification of radioactive waste

The types of radioactive waste are divided into:

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

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

Freed from control

There are types of radioactive waste in which the concentration of radionuclides is very low. They are practically harmless to the environment. Such substances are in the exempt category. The annual amount of radiation from them does not exceed the level of 10 μ3v.

Radioactive waste management rules

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;
• the protection of the environment from hazardous substances should be improved;
• control the process of waste disposal;
• indicate the level of exposure at each repository on the basis of documents;
• control the accumulation and use of radioactive elements;
• in case of danger, accidents must be prevented;
• in extreme cases, it is necessary to eliminate all the consequences.

What is the danger of radioactive waste

To prevent such an outcome, all enterprises using radioactive elements undertake to use filtration systems, control production activities, decontaminate and dispose of waste. This helps prevent ecological disaster.

RW hazard level 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 area, the number of people who live on it. Since these substances are deadly, it is necessary in the event of an accident to liquidate the catastrophe 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 storage of waste. It involves the collection of radioactive waste, their transfer for disposal. The means and methods necessary for storage are established by documents. For them, special containers are made of rubber, paper and plastic. They are also stored in refrigerators, metal drums. RW transportation is carried out in special sealed containers. In transport, they must be securely fixed. Transportation can only be carried out by companies that have a special license for this.

Processing

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

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

Collection and disposal

Collection and disposal of radioactive waste should be carried out in places where there are no non-radioactive elements. It should be taken into account state of aggregation, waste category, their properties, materials, half-life of radionuclides, potential hazard of the substance. In this regard, it is necessary to develop a strategy for radioactive waste management.

For collection and disposal, you need to use specialized equipment. Experts say that these operations are possible only with medium and low active substances. During the process, each step must be monitored to prevent an environmental disaster. Even a small mistake can lead to accidents, 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.

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

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

• separate household waste, and then apply methods for its safe recycling;
• build waste disposal plants;
• form specially equipped sites for the disposal of hazardous substances;
• create new technologies for the processing of secondary raw materials.

Countries such as Japan, Sweden, Holland and some other states take radioactive waste disposal and household waste disposal seriously.

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

When the waste appeared

With the advent of man, waste appeared on Earth. But if the ancient inhabitants did not know what light bulbs, glass, polyethylene and other modern achievements were, then now scientific laboratories are working on the problem of destroying chemical waste, which attracts talented scientists. It is still not completely clear what the world will face in hundreds, thousands of years if waste accumulates.

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

Classification

In Russia, the Federal Law No. 190 of 11.07.2011 is in force, which reflects the main Regulations for the collection and management of radioactive waste. The main criteria for assessing the classification of radioactive waste:

• removable - radioactive waste that does not exceed the risks of radiation exposure and costs during extraction from a storage facility with subsequent disposal or handling.
• special - radioactive waste that exceeds the risks of radiation exposure and costs for subsequent disposal or extraction.

Sources of radiation are dangerous for their destructive effect on the human body, and therefore the need to localize active workings is extremely important. Nuclear power plants produce almost no greenhouse gases, but there is another complex problem associated with them. Tanks are filled with spent fuel, they remain radioactive for a long time, and the amount is constantly growing. Back in the 1950s, the first research attempts were made to solve the problem of radioactive waste. There were proposals to send them into space, store them on the ocean floor and other hard-to-reach places.

Landfill plans vary, but land use decisions are contested public organizations and environmentalists. State scientific laboratories have been working on the problem of destroying the most dangerous waste almost since the advent of nuclear physics.

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

In nuclear power plants, the following happens: The uranium oxide fuel rod is in a stainless steel cylinder. It is placed in a reactor, uranium decays, releases thermal energy, it drives a turbine and produces electricity. But after only 5 percent of the uranium has been radioactively decayed, the entire rod becomes contaminated with other elements and must be disposed of.

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

Waste disposal

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

The requirements of a foreign buyer are simple: he takes fuel, uses it, and returns the radioactive waste. They are taken to the plant railroad, robots are engaged in loading, and it is mortally dangerous for a person to approach these containers. Sealed, durable containers are installed in special wagons. A large wagon is turned over, containers with fuel are laid with special machines, then it is returned to the rails and by special trains with warned railway services, the Ministry of Internal Affairs is sent from the nuclear power plant to the point of the enterprise.

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

Specialized factories process waste of medium and low activity. Sources - everything that surrounds people in everyday life: irradiated parts of medical devices, parts of electronic equipment and other devices. They are brought in containers in special vehicles that deliver radioactive waste by ordinary roads, accompanied by the police. Outwardly, they are distinguished from the standard garbage truck only by the color. At the entrance there is a sanitary inspection room. Here everyone has to change clothes, change shoes.

Only after that you can get to workplace where it is forbidden to eat, drink alcohol, smoke, use cosmetics and be without overalls.

For employees of such specific enterprises, this is a routine job. The difference is one: if a red light suddenly turns on on the control panel, you must immediately run away: the sources of radiation can neither be seen nor felt. Control devices are installed in all rooms. When everything is in order, the green lamp is on. The working rooms are divided into 3 classes.

1 class

Waste is recycled here. In the furnace, radioactive waste is converted into glass. It is forbidden for people to enter such premises - it is deadly. All processes are automated. You can enter only in case of an accident in special protective equipment:

• insulating gas mask (special protection made of lead, absorbing radioactive radiation, shields to protect the eyes);
• special uniforms;
• remote means: probes, grips, special manipulators;

By working in such facilities and following impeccable precautions, people are not exposed to the risk of radiation exposure.

2nd grade

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

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

Grade 3

This includes corridors and ventilation shafts. A powerful air conditioning system works here. The air is completely replaced every 5 minutes. A radioactive waste processing plant is cleaner than a good housewife's kitchen. After each transportation, cars are watered with a special solution. Several people work in rubber boots with a hose in their hands, but the processes are automated so that they become less laborious.

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

Radioactive waste is hidden under seven locks. The depth of the bunkers is usually 7‒8 meters, the walls are reinforced concrete, while the storage is filled, a metal hangar is installed above it. Highly protected containers are used to store highly hazardous waste. There is lead inside such a container, there are only 12 small holes about the size of a gun cartridge. Less hazardous waste is placed in huge reinforced concrete containers. All this is lowered into the shafts and closed with a hatch.

These containers can then be removed and sent for further processing in order to finally dispose of radioactive waste.

The filled storages are covered with a special type of clay, in the event of an earthquake, it will glue the cracks. The storage is covered with reinforced concrete slabs, cemented, asphalted and covered with earth. After that, the radioactive waste does not pose a danger. Some of them decay into safe elements only after 100-200 years. On the secret maps, where the vaults are marked, it is worth the stamp "keep forever"!

The landfills where radioactive waste is buried are located at a considerable distance from cities, towns and water bodies. Nuclear energy, military programs - problems that concern everyone global community... They consist not only in protecting a person from the influence of sources of radioactive waste generation, but also carefully protecting them from terrorists. It is possible that landfills where radioactive waste is stored may become an object for a target in military conflicts.