Radioactive river flowing. Field studies of the consequences of the dumping and burial of radioactive waste into the seas of the northern and Far Eastern regions of the Russian Federation
In accordance with Article 4 “Classification of radioactive waste” of the federal law on radioactive waste management, “criteria for classifying solid, liquid and gaseous waste as radioactive waste are established by the Government of the Russian Federation.” When preparing a draft resolution of the Government of the Russian Federation on the classification of radioactive waste, the most pressing question arose about the criteria and numerical boundaries for classifying waste of various states of aggregation as radioactive waste.
Currently, participants in the discussion on future criteria for classifying waste as solid, liquid and gaseous radioactive waste have not developed a consensus on this issue. This situation is associated with different attitudes towards international recommendations and experience of the leading industrial countries of the world (USA, France, UK, etc.), as well as with the peculiarities of the Russian system of legal regulation of relations in the field of radioactive waste management.
In domestic regulatory documents and the practice of their application, the numerical values of the boundaries for classifying waste as RW play the role of “sacred numbers”, while in the recommendations of international authoritative organizations (IAEA, ICRP) they serve only as guidelines, determined with an accuracy of an order of magnitude, practical application which are guided by common sense and a differentiated approach. In the latter case, it is fundamentally important only to determine the limit above which waste is considered as RW.
The classification system for solid radioactive waste, presented in the IAEA Safety Guide, defines the range of all waste management activities aimed at ensuring the long-term safety of the population.
According to IAEA documents, “radioactive waste is waste containing radionuclides or contaminated with radionuclides with a concentration or activity above the exemption level established by the regulatory body.” Waste containing a mixture of radionuclides of artificial origin is classified as radioactive waste if
(1),
Where a i – specific activity of radionuclide i in waste, Bq/kg;
X i – specific activity of radionuclide i in waste, if not exceeded, it can be exempted from regulatory control, Bq/kg.
Regulatory requirements are not imposed on waste containing radionuclides of artificial origin if J≤ 1.
In some cases, when a 1 > X i , in accordance with the principle of optimization, a graded approach may be adopted in which the regulatory body may decide (if the national regulatory framework allows) that the optimal option is not to apply regulatory requirements to wastes for which the value of J exceeds one several times - for example, up to ten times.
To automatically remove from regulatory control "moderate quantities" (maximum of the order of one ton) of solid material, the specific activity and activity "exemption levels" for individual radionuclides specified in Table I-1 of Annex I of the International Basic Safety Standards are applied.
It should be noted that not all developed countries have fully accepted the IAEA recommendations. For example, the classification systems for radioactive waste in the USA, France and the UK differ markedly from the IAEA recommendations; in the UK, legislation developed for radioactive waste does not apply to very low level waste.
The concept of “exception levels” for “moderate quantities” of solid material is not fully reflected in Russian regulations.
Appendix 3 to OSPORB-99/2010 shows the specific activity values of man-made radionuclides, below which unlimited use of materials is allowed, regardless of the state of aggregation (except for food raw materials, food products, drinking water and animal feed). But these specific activities fully correspond to the levels of exclusion/exemption (in terms of specific activity) from control of only solid material given in IAEA documents - thus, Appendix 3 to OSPORB-99/2010 cannot be applied to gaseous and liquid materials. Therefore, this document caused sharp criticism from the Russian Ministry of Natural Resources, Rostechnadzor and a number of leading specialized organizations (STC NRS, VNIIAES, IBRAE RAS, etc.), including at a meeting of the Russian Scientific Commission on Radiological Protection (RNRP).
According to the established practice in Russia, solid waste that cannot be exempted from radiation control, but in which the specific activities of radionuclides do not exceed the values established in Appendix 4 to NRB-99/2009, do not belong to RW. The management of such waste (very low-level waste - VLLW) is regulated by special sanitary rules SP 2.6.6.2572-2010 “Ensuring radiation safety when handling industrial waste from nuclear power plants containing man-made radionuclides” and guidance R 2.6.5.04 – 08 “Hygienic requirements for handling with industrial waste at the Federal State Unitary Enterprise "Northern Federal Enterprise for Radioactive Waste Management".
With the formal adoption of IAEA recommendations, the reduction of the existing limits for classifying solid waste based on the specific activity of radionuclides as SRW to the levels of exemption from control will inevitably lead to a multiple increase in SRW stored and generated at the NPP sites of Rosenergoatom Concern OJSC and an exorbitant increase in the cost of their transfer to the national operator. This problem will be further aggravated at the stage of decommissioning of power units.
Decision-making on a new RW classification system in Russia should be preceded by careful work on the technical and economic assessment of its various options when implemented at various nuclear fuel cycle enterprises. Particular attention should be paid to minimizing the corruption component, since the “issue price” can amount to tens of billions of rubles. Therefore, the process of preparing a draft government resolution on the classification of radioactive waste should be as transparent as possible; a large number of highly qualified specialists must be involved in its preparation and discussion.
At this stage, it is extremely important to prevent the hasty adoption of a resolution of the Government of the Russian Federation on the classification of radioactive waste.
Solid radioactive waste
Currently in Russia, solid waste according to the radiation factor is divided into three groups:
– waste exempt from radiation control that meets the following conditions:
(2),
Where Ψ i – specific activity of radionuclide i, at which unrestricted use of materials is allowed, is established in accordance with IAEA recommendations in Appendix 3 to OSPORB-99/2010;
– very low-level waste, for which the following conditions are met:
(3),
Where MZUA i is the minimum significant specific activity of radionuclide i, established in Appendix 4 to NRB-99/2009;
– radioactive waste that meets the following conditions:
In OSPORB-99/2010, the above-mentioned “removal levels” for moderate quantities of solid material (no more than 1 ton) by specific activity are adopted as the MSUA, which ensures the radiation safety of personnel when handling RW. The requirement for safe disposal of radioactive waste is an independent attribute of the radioactive waste management process.
In accordance with IAEA recommendations, there is no need for a high degree of protection and isolation of such waste; they can be disposed of in near-surface storage facilities such as landfills with limited regulatory control. Typical wastes in this category may include soil and debris (crushed stone) with low radionuclide content. At Russian NPPs, VLLW includes bottom sediments of spray ponds, sludge from sewage treatment facilities, sludge deposits from cooling towers, soil from filtration fields, etc. Safe handling (including disposal), accounting and control of solid VLLW is ensured by compliance with relevant sanitary rules and guidelines.
As of January 1, 2012, the nuclear power plants of the Rosenergoatom concern had accumulated approximately 163,000 m3 of solid radioactive waste, of which low-level waste constituted approximately 138,300 m3. The average rate of formation of LLW is approximately 5000 m 3 per year, VLLW is 10,000 m 3 per year.
JSC VNIIAES considered two possible criteria for classifying solid waste as radioactive waste:
- I 1 >1 (SRW includes solid waste that is not subject to withdrawal or release from regulatory control);
- I 2 >1 (the limit on the specific activity of radionuclides for classifying solid waste as SRW remains at the existing level).
In the first option, VLLW is SRW. The specific costs of nuclear power plants for their management, including the mandatory transfer of unconditioned radioactive waste to the national operator, will be at least $5,000 per cubic meter. The total annual costs for handling (including the disposal stage) of VLLW NPP of the Rosenergoatom concern will be $5 * 10 7 .
If the second option is adopted, VLLW will not fall under the SRW category. The specific costs for their disposal at the NPP site in accordance with the sanitary rules SP 2.6.6.2572-2010 will be about $300 per cubic meter (taking into account the experience of burying several thousand tons of bottom sediments from the spray pools of the Balakovo NPP and sludge from the treatment facilities of the Kursk NPP CFC). Total annual costs will be $3*10 6 .
Thus, the difference in the costs of VLLW disposal generated during the operation of Rosenergoatom Concern NPPs, with different options for classifying solid waste as SRW per year, is $4.7 * 10 7 (1.4 billion rubles as of January 1, 2012).
Let us consider a similar relationship for the management of VLLW generated during the decommissioning of nuclear power plants. Table 1 shows that the costs of VLLW management (including disposal) under the first option are approximately 17 times higher than under the second option.
Table 1. Costs of VLLW management during NPP decommissioning for various options for classifying them as SRW
Power unit type |
VLLW management costs, $ |
|
VLLW – SRW |
VLLW is not SRW |
|
Currently, there are 11 power units with RBMK-1000, 11 power units with VVER-1000 and six power units with VVER-440 in operation. The costs of radioactive waste management (including disposal) when decommissioning these units if the first option is adopted will be approximately $680 million (20 billion rubles in 2011 prices) higher than with the second option
It should be noted that the spread in the values of the quantities MZUA/Ψ for various radionuclides reaches several orders of magnitude. For example, for a large number of radionuclides (31 Si, 32 P, 38 Cl, 42.43 K, 47 Ca, 47 Sc, 51.52m,56 Mn, 52 Fe, 55.58m,60m,61.62m Co, 89 Sr , 65 Ni, etc.) these values are 1, for 131 I, 239 Pu, 241 Am – 10, for 60 Co, 90 Sr, 134,137 Cs – 102, for 103 Ru – 103, for 3 H, 14 C – 104. This result is a logical consequence of the fact that the quantitiesMZUA andΨ calculated based on different exposure scenarios for personnel and the public.
In the extremely undesirable conditions of the hasty adoption of a resolution on the classification of radioactive waste, it is proposed to preserve the existing “MSUA concept” for classifying solid waste as SRW with its subsequent replacement with a more reasonable concept. At the same time, from our point of view, it is advisable to take the boundaries of classifying solid waste as solid radioactive waste based on the specific activities of a number of radionuclides that are most significant in the management of radioactive waste from domestic nuclear power plants as different from their MZUA (Table 2), as established in the RW classification system in the USA.
Table 2. Limits for classifying solid waste as SRW based on the specific activity of radionuclides
Radionuclide |
Transuranic elements |
|||||||||
Specific activity, Bq/g |
Liquid radioactive waste
Currently, among the overwhelming number of experts, there is a consensus regarding the presentation of the lower limit for classifying liquid waste as liquid radioactive waste in units of intervention levels (IL) based on the content of individual radionuclides in drinking water. In general, the proposed criterion is written as:
(5),
Where q 1 – specific activity of radionuclide i in liquid waste, Bq/kg;
UV i – level of intervention for the content of radionuclide i in drinking water, Bq/kg;
k – dimensionless proportionality coefficient.
In the earlier OSPORB-99 (before the introduction of OSPORB-99/2010) and the current Rostechnadzor document NP 058-04 k = 10. The inconsistency of this concept was clearly shown at the RNKRZ meeting on June 21, 2010 using the example of whey from private farms in the Bryansk region , in which the specific activity of 137 Cs sometimes exceeds 10*HC (110 Bq/kg). In such cases, the serum must be treated like radioactive waste - not poured into the sewer, but solidified and sent for disposal, and have the appropriate license. Therefore, most experts, with the exception of the Russian Ministry of Natural Resources and Rostechnadzor, propose to take k in the range of values from 30 to 100, depending on the radionuclide.
A return to the “10*HC concept” for classifying liquid waste as liquid radioactive waste takes part of the Russian nuclear energy industry, based on power units with VVER-type reactors, outside the legal framework. The fact is that, in accordance with physical principles (boron regulation of reactivity in double-circuit pressurized water nuclear reactors), the actual specific activity of tritium in unbalanced waters of nuclear power plants with VVER reaches several MBq/kg, which is hundreds of times higher than the corresponding level of intervention for the tritium content in drinking water (UVT = 7600 Bq/kg), and, according to modern concepts, cannot be reduced other than by dilution. This is practiced as an exception at nuclear power plants with PWR reactors in a number of leading countries in the world, for example, in the USA, but is prohibited by domestic sanitary rules (clause 3.12.10 OSPORB-99/2010).
Indeed, according to the IAEA, “in light water reactors, tritium in the form of tritiated water is an important source of radiation in liquid and gaseous emissions discharged into the environment, since there is currently no cost-effective method for separating it from the waste stream.” . This creates problems for the discharge of tritrium-containing unbalanced water from NPPs with VVER into water bodies. Currently, a conservative estimate of the annual effective dose for a critical group of the population due to such a discharge does not exceed several μSv, which corresponds to an absolutely acceptable radiation risk for the population (less than 10 -6 / year) and, in accordance with the optimization principle, does not require additional radiation protection measures.
Theoretically, the solution to the “tritium problem” at NPPs with VVER, if the “10*HC concept” is adopted, is possible in two ways:
- keeping tritium-containing unbalanced waters in special tanks at industrial sites of nuclear power plants for several decades until the tritium content in them decreases (T1/2 = 12.3 years) by two orders of magnitude;
- solidification of such waters with subsequent placement at a VLLW disposal site in accordance with sanitary rules SP 2.6.6.2572-2010.
Assessments carried out at JSC VNIIAES showed that these works are not only unacceptable for the Russian nuclear industry in terms of costs, but also unjustified from the standpoint of optimizing radiation protection. Solidification and/or storage of tritium-containing liquid industrial waste can lead to increased exposure of personnel, but will have virtually no effect on radiation risks for the population in the area where the nuclear power plant is located. The radiation risk for the population under any treatment option for tritium-containing unbalanced waters remains very small (less than 10 -6 /year).
A radical solution to the “tritium problem” is the refusal to apply restrictions on the specific activity of radionuclides to discharges into water bodies, if their radiation exposure does not lead to a radiation dose to the population exceeding 10 μSv per year, at which the radiation risk for the population is absolutely acceptable (less than 10 - 6/year). This proposal is universal and comprehensive; it takes the Russian nuclear energy industry out of a situation where, due to the formal exceeding of the limit for classifying liquids as liquid radioactive waste, even in compliance with the extremely strict dose restrictions on discharge, the operation of NPPs with VVER becomes illegitimate. Meanwhile, according to the International Basic Safety Standards and current sanitary rules and regulations, regulatory requirements do not apply to radiation sources that create an annual effective dose of no more than 10 μSv.
A solution to the “tritium problem” may also be based on IAEA recommendations for the application of a differentiated approach by the regulatory body to the implementation of a protection and safety system, according to which “the application of regulatory requirements should be proportionate to the radiation risks associated with the exposure situation.” Obviously, a differentiated approach makes it possible to exclude the introduction of additional restrictions on the discharge (including on the specific activity of tritium), the radiation impact of which on the population does not exceed the minimum significant dose (10 μSv/year) established in NRB-99/2009 and OSPORB-99 /2010 as a lower dose limit when optimizing radiation protection of the population.
Consequently, the application of the “10*HC concept” to the discharge of tritium with purified unbalanced waters from nuclear power plants is unjustified.
Based on the above, it is proposed to supplement the draft resolution of the Government of the Russian Federation on the classification of radioactive waste with the following note: “the criteria for classifying liquid waste as liquid radioactive waste do not apply to discharges of man-made radionuclides into the environment, provided they are carried out in accordance with the standards for permissible discharges, calculated based on the radiation dose persons from the critical group of the population 10 μSv per year and permits issued in accordance with the legislation of the Russian Federation.”
This solution is fully consistent with IAEA Guide No. WS-G-2.3 “Regulatory Control of Radioactive Discharges to the Environment” and Requirement 31 “Radioactive Wastes and Discharges” of the International Basic Safety Standards.
Gaseous radioactive waste
In many countries of the world, the permissible human volume activity (VAR) in the air is taken as the limit for classifying gaseous waste as radioactive, the release of which into the atmosphere is prohibited. The question is which person (employee or representative of the population) to associate this value with.
The specified criterion based on the DOA of us, as the Russian Ministry of Natural Resources insists, cannot be considered suitable for Russia for two reasons. In this case, one should accept DOA pers =DOA us, since otherwise the personnel should be allowed to breathe gaseous radioactive waste (DOA pers >> DOA us). The achieved level of radiation safety at NPPs of Rosenergoatom Concern OJSC does not allow guaranteeing such air quality in work areas, especially when personnel perform repair work. This requirement is even more problematic to meet at other enterprises in the industry. It is proposed to accept the DOA pers values established for individual radionuclides (except for inert radioactive gases, IRG) in Appendix 1 to NRB-99/2009 as the boundary for classifying gaseous waste as radioactive.
In addition, establishing a limit value for the volumetric activity of emissions at the level of the AE can create real difficulties for both existing and new nuclear power plants: permissible emission standards (AE) will not be observed, while the actual radiation risk for the population in the areas where the NPP is located will certainly be acceptable (less than 10-6 year-1). For most other nuclear fuel cycle enterprises, this requirement will be impossible to meet without huge capital expenditures for the reconstruction of purification systems.
The permissible volumetric activity of emitted radionuclides should be determined not in relation to gaseous radioactive waste, but in accordance with the DV standard, as was regulated in clause 3.12.5 OSPORB-99: “Gaseous radioactive waste is subject to exposure and (or) purification on filters in order to reduce its activity to levels regulated by permissible emissions, after which they can be released into the atmosphere.”
Conclusion
With all the diversity of existing opinions expressed by the participants in the discussion regarding possible classification schemes for radioactive waste, the boundaries for classifying waste of various states of aggregation as radioactive waste are one way or another proposed to be established on the basis of the specific activities of man-made radionuclides, at which unlimited use of materials is allowed (Appendix 3 to OSPORB-99/ 2010), MZUA (Appendix 4 to NRB-99/2009), UV (Appendix 2a to NRB-99/2009) and DOA (Appendix 1 and 2 to NRB-99/2009).
The indicated values are permissible levels of single-factor exposure (for one radionuclide, route of entry or type of external exposure), which are derived from the main dose limits. They quite often undergo changes due to the refinement of radiobiological models and dosimetric base. In this regard, the decree of the Government of the Russian Federation on the classification of radioactive waste must indicate that the values of these quantities are established by sanitary rules and regulations.
When establishing the boundaries for classifying waste of various states of aggregation as RW, one should proceed from the rational use of resources allocated to solve the problem of radioactive waste disposal in Russia, while unconditionally complying with modern safety requirements for personnel, the population and the environment. In conditions of limited resources and a huge volume of radioactive waste, their artificial increase due to an unreasonable reduction in the boundaries of classification of waste as radioactive waste will inevitably lead to a dispersal of forces and resources, an increase rather than a solution to problems. Obviously, in this case, the budget will be spent through expensive disposal of waste containing non-hazardous amounts of radionuclides. Therefore, decisions on these boundaries must be verified and well justified, taking into account diverse factors.
Authors
Literature
1. Federal Law of July 11, 2011 No. 190-FZ “On the management of radioactive waste and on amendments to certain legislative acts of the Russian Federation.”
2. “Criminal Code of the Russian Federation” dated June 13, 1996 No. 63-FZ (as amended on December 7, 2011), with amendments and additions coming into force on December 19, 2011.
3. International Atomic Energy Agency. Safety Standards Classification of Radioactive Waste, General Safety Guide, No. GSG-1, IAEA, Vienna, 2009.
4. IAEA Safety Glossary. Terminology used in the field of nuclear safety and radiation protection. – 2007.
5. Draft Safety Requirements: Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards Revised Edition of IAEA Safety Series No. 115.
6. International Atomic Energy Agency. Application of the Concepts of Exclusion, Exemption Clearance, Safety Guide No.RS-G-1.7, IAEA, Vienna, 2004.
7. International Atomic Energy Agency. Derivation of Activity Concentration Levels for Exclusion, Exemption and Clearance, draft report, IAEA, Vienna, 2004.
8. SP 2.6.1.2612-10 Basic sanitary rules for ensuring radiation safety (OSPORB-99).
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11. R 2.6.5.04 – 08. Manual “Hygienic requirements for the management of industrial waste at the Federal State Unitary Enterprise “Northern Federal Enterprise for Radioactive Waste Management” (R ONAO SevRAO-08).
12. NP 058-04. Safety when handling radioactive waste. General provisions.
13. International Atomic Energy Agency. Radiation Protection Aspects of Design for Nuclear Power Plants, Safety Guide No.NS-G-1.13, IAEA, Vienna, 2005.
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Kolychev B. S. Results of the meeting on the problem of dumping radioactive waste into the seas and oceans// Atomic Energy. Volume 10, issue. 6. - 1961. - P. 634-635.
Results of the meeting on the problem of dumping radioactive waste into the seas and oceans
In January 1961, a meeting of a group of legal and technical experts was held in Vienna on the legal aspects of the problem of dumping radioactive waste into the seas and oceans; the meeting was organized by the International Atomic Energy Agency. The meeting was attended by experts from 11 major maritime powers: Brazil, Great Britain, Holland, India, Poland, USSR, USA, Finland, France, Yugoslavia, Japan. In addition, representatives of the International Maritime Consultative Commission, UNESCO and other organizations, as well as observers from some countries, participated in the meeting.
The meeting was preceded by a group of technical experts chaired by the Swedish scientist Brynielsson; As a result of this work, a report was prepared, the main recommendation of which can be considered the conclusion that it is permissible to discharge waste of medium and low levels of activity into the seas and oceans.
At the very beginning of the meeting, a group of Soviet experts made a statement about the inadmissibility of dumping radioactive waste into the seas and oceans, based on the following arguments.
1. Currently, the Earth’s atmosphere is contaminated with radioactive substances and is a source of radiation. The continuing fallout of nuclear explosion products from the atmosphere leads to pollution of the World Ocean and its living resources. Due to the accumulation in the human body of long-lived isotopes coming from the environment, in the coming years the content of isotopes in the human body will be close to the maximum permissible levels, and in a significant population these levels will be exceeded. Therefore, further pollution of the World Ocean by dumping radioactive waste into it is unacceptable.
2. Modern international law prohibits any pollution of the sea and its living resources. Consequently, states that dump radioactive waste leading to sea pollution violate international law.
3. According to currently available data, radioactive waste removed at sea can quite quickly return to humans in a wide variety of forms. Marine organisms are capable of accumulating activity two to three orders of magnitude higher relative to its content in water. Necessary
study in detail the food chains in the sea and the concentration and discrimination coefficients for at least the most dangerous isotopes, before talking about any additional discharges.
4. No matter how small exposure to radiation causes undesirable somatic and genetic consequences (even fatal), therefore, any excess of radiation levels above natural levels is dangerous to the life and health of all humanity.
5. The establishment of limited discharge zones cannot protect adjacent areas of the seas and oceans from pollution, since the World Ocean must be considered as a single whole. Due to physical and biological transport, radioactivity will spread far beyond the established zones.
6. Discharges of radioactive waste in territorial waters cannot be considered an internal matter of the state, since due to migration through the above routes, radioactivity can harm the population of neighboring states.
7. It is almost impossible to monitor compliance with discharge values for the following reasons:
A) currently there are no established maximum permissible concentrations of individual isotopes in seawater, much less standards for emissions of general activity;
B) there is no data on the content of radioactive isotopes in sea water, in individual marine organisms, in various parts of the seas and oceans;
C) there are no uniform methods for determining small concentrations of radioactive isotopes in sea water.
Despite the statement of the group of Soviet experts, the meeting nevertheless decided to base its work on the Brynielson report, which allowed the dumping of medium and low-level radioactive waste into the seas and oceans. This assumption was especially dangerous because the Brynielson report defined high-level waste as waste containing hundreds of curies per liter or more, and low-level waste as waste containing millicuries per liter; therefore, for intermediate level wastes the entire activity range from millicuries to hundreds of curies per liter remained.
Establishing any level of radioactivity for dumped waste, especially with the broad interpretation laid down in Brynielson’s report, does not determine anything, and most importantly, does not guarantee against the introduction of large quantities of activity into the seas.
Whatever gradations are established, any initial level of radioactive waste can be brought by preliminary dilution to the level permitted for discharge, since in this case the total amount of discharged activity does not decrease. Even if we apply the definition of this level to waste at the time of its generation, then even in this case there are no sufficient guarantees against discharges of large amounts of activity.
As is known, the waste obtained after the dissolution of fuel elements is currently evaporated to reduce the volume for the purpose of disposal. In some cases (especially when dissolving fuel elements with shells made of stainless steel or other sparingly soluble alloys) prior to evaporation, waste is obtained with a level of activity that corresponds to the intermediate level category, and, therefore, as recommended by the Brynielson report, it can be discharged into the sea. Thus, determining the level of activity of waste at the time of its formation does not limit the discharge of large masses of activity into the seas and oceans.
During the meeting, discussions repeatedly arose on all aspects of the problem, during which Soviet experts, together with representatives of Poland, managed to convincingly defend the provisions contained in the statement of the group of Soviet experts. In addition, the Soviet delegation showed that there are already ways to dispose of radioactive waste without polluting the environment.
Currently, taking into account the results of scientific research carried out in many countries, it is completely possible to create production facilities for the chemical processing of waste of any level in order to prevent the danger of the spread of radioactivity.
High-level waste can be concentrated by evaporation with subsequent burial of the resulting small volumes in special containers located underground, which is essentially what is now practiced by all countries with a nuclear industry.
Technologically and economically accessible methods now also exist for processing large volumes of intermediate (1 curie/l and below) and low radioactivity waste.
Research by scientists from Great Britain, the USSR, the USA, France and other countries has shown that the use of coagulants (iron, calcium) under a certain regime in combination with ion exchange, electrophoresis and evaporation makes it possible to achieve very high purification rates. At the same time, the bulk of activity (99.8 - 99.9%)
It is concentrated in relatively small volumes of sediment and still remains, which can also be securely buried in isolated containers. The resulting waters of very low activity should be used for technical needs within the enterprise itself. Thus, the cycle is completely closed and no waste is released into the external environment.
We should also not forget the fact that the extraction of long-lived radioisotopes Sr90 and Cs137 will significantly facilitate the further processing of liquid solutions and will provide some economic benefit from their partial use for radiation sources.
Currently, the possibility of vitrification of highly active concentrates has been established, which makes it possible to reliably fix the activity, preventing its further spread. Extensive research carried out both in the development of vitrification methods and in studying the properties and storage conditions of vitrified materials confirms the promise of this method, which makes it possible to significantly reduce the volume of discharges and further increase the reliability of disposal from the point of view of safety requirements.
The issue of waste generated from the use of isotopes and radiation sources in research laboratories, hospitals and enterprises is somewhat more complicated. To process such waste, it is advisable to create installations for centralized processing of radioactive solutions. At these installations, using the above methods, waste can be brought to sanitary standards adopted for open reservoirs, and the concentrated activity can be reliably buried in special burial grounds. These principles have been accepted and implemented in the USSR.
Nuclear ships must have reserve tanks for temporary storage of radioactive discharges. All waste from nuclear ships must be processed at shore bases in accordance with the methods recommended above.
Thus, if we accept the costs of creating production facilities for processing radioactive waste as a prerequisite for the development of nuclear enterprises, the problem of safe waste disposal from these enterprises will be completely solved.
As a result of a comprehensive and objective discussion of the problem, which took place in a very friendly atmosphere, the meeting agreed with the main provisions of the expert platform and came to the conclusion that for a number of important scientific and technical problems, the Brynielson report does not provide answers, which is why the meeting cannot currently formulate or recommend a convention or other international agreement.
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- 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.
The cause of three major accidents that occurred at the Mayak PA was the radioactive waste storage system. The first emergency situation arose as a result of the uncontrolled discharge of liquid radioactive waste into the Techa River. The radiochemical plant, which was commissioned in March 1949, began discharging radioactive wastewater in March 1949. Initially, the discharge was provided for by technical regulations. This was low-level waste after preliminary treatment.
But already from the beginning of 1950, in the period from January to March, there was a sharp increase in discharges into the Techa River. In addition to the scheduled wastewater, unauthorized, so-called “wild” discharges with an activity of up to one hundred thousand Curies per day, not provided for by the technological process, began to be discharged into the Techa.
The highest values of the exposure dose rate of gamma radiation were observed precisely during the period of massive discharges in 1950-1951 and reached from 50,000 µR/s at the discharge site to 1500 µR/s on the shore of the Metlinsky pond. Of particular danger were contaminated bottom sediments of storage ponds, river beds and soils of the flooded part of the floodplain. In this regard, a decision is made to flush the Koksharov and Metlinsky ponds. The maximum possible amount of water was released into the Techa River, and along with this water - a large amount
radioactive sludge.
In order to localize and store large volumes of radioactive waste, at the end of 1951, the discharge of the main technological waste from production was switched to Lake Karachay. The total intake of radioactive substances into the river. The flow has decreased significantly.
Despite the reduction in discharges, the content of radioactive substances in river water continued to remain at a high level. This required the adoption of long-term comprehensive measures aimed at blocking the upper reaches of the river with a system of blind dams. In November 1956, a dam and reservoir was built - the Shubinsky pond to intercept liquid radioactive waste, which reduced the flow of radionuclides into the lower reaches of the river. Later,
under the containers of the created pond, Lake Berdyanish and the southern canal are drained and washed. About 10 million cubic meters were dumped into the Shubinsky pond. meters of radioactive water with silt, the level of the water surface of the pond rose by 107 cm, the specific activity of the pond water increased 10 times and amounted to 400 thousand Curies/l. Almost immediately, strong filtration through the body of the Shubinsky Pond dam was discovered, and urgent strengthening of the dam began. And then the construction of the closing dam No. 11, with the help of which the most polluted
the upper reaches of the river were isolated from other areas.
The hydrographic picture of the territory was radically changed by the activities of the Mayak PA. Until the mid-50s, the source of the Techa River was connected with Lake Irtyash, then the river passed through Lake Kyzyltash and received the waters of a small tributary - the Mishelyak River, flowing from Lake Ulagach. After 1965, the beginning of the river is considered to be the downstream of the dam of reservoir No. 11. The regulated flow of lakes and the Mishelak River is cut off from the upper reaches of the river and is directed through a system of left-bank and right-bank canals, bypassing the technological ponds of the Techensky cascade into the downstream of pond No. 11. Reservoir No. 11 itself has been operated in a non-flowing mode since 1965.
By 2004, the water level in the pond had reached a critical level, and weakened zones were identified in the upper part of the dam. There was a real threat of destruction of the dam, which could lead to a major environmental disaster. The condition of the dam closing the Techa cascade has become the most discussed problem, right up to the presidential level. About 800 million rubles were allocated for its reconstruction. federal funds. An additional impervious screen was built in the crest part of the dam, a concrete tooth with a depth of 7 to 13 meters was installed along the entire perimeter of the dam, the dam was additionally reinforced with soil and sheet piles. The dam corresponds to the second reliability class, this is a very high reliability class. The measures at the Techa cascade of reservoirs, completed in 2008, were of an anti-crisis nature. A radical solution to the problem of the Techa cascade as a whole is needed.
Today, the radiation situation in the Techa River basin in the Kurgan region is formed by contaminated areas of the floodplain, leaching of activity from the bottom sediments of the river bed, filtration inflows and the Asanovsky swamps.