Relevance
The 'Strategy for Achieving Carbon Neutrality in the Republic of Kazakhstan by 2060', approved by decree of the President of the Republic of Kazakhstan, K. K. Tokayev, stipulates that nuclear power plants will be included in the energy mix as a stable source of energy. Consistent work is therefore underway to formulate a vision for the development of nuclear energy and prepare a decision on the construction of a nuclear power plant (NPP). This decision will undoubtedly be based on existing expertise and human resources in this field, as well as the results of scientific research, which together form the scientific and technological foundation for nuclear energy development.
Scientific research in support of NPP development generates high-quality, objective data that is necessary for making informed decisions about technology selection and ensuring the safe, efficient operation of NPPs. Initially, the focus should be on a few critical aspects of NPP operation: the predictive assessment of the nuclear-physical characteristics of promising reactor types; the definition of a radioactive waste (RW) and spent nuclear fuel (SNF) management concept; and the formulation of requirements for the design and composition of a radiation monitoring system in the vicinity of the NPP. The selection of these aspects for research is motivated by the prospect of obtaining new data and their significant socio-economic impact.
A key aspect of operating a nuclear power plant is having a clear understanding of, and the ability to predict, the physical processes occurring within the nuclear reactor. This can be achieved by developing computational models that enable these processes to be simulated in detail. Developing computational models using proven specialized software packages and applying them provides insight into critical reactor operating characteristics such as reactivity, control system effectiveness, energy release field and coolant parameters. New data on nuclear-physical characteristics obtained during research, along with the acquired expertise, will form the basis for creating algorithms to control the nuclear reactor and its fuel cycle.
The management of spent nuclear fuel and radioactive waste is a critical aspect of the nuclear power industry. Each country and nuclear power plant operator develops its own programs and strategies for managing spent fuel and radioactive waste, taking into account specific conditions. For Kazakhstan, which is in the early stages of introducing nuclear energy, it is particularly important to determine the right direction and develop optimal approaches to managing spent nuclear fuel (SNF) and radioactive waste (RAW) that will minimize their environmental impact. The most optimal concept currently appears to be the long-term controlled storage of SNF, which is considered a valuable resource. This ensures the future possibility of reprocessing SNF and reusing fissile materials in the nuclear fuel cycle. This will contribute to the more complete utilization of resource potential. To ensure such long-term storage, scientifically sound data on the radiation resistance of materials used for storage containers is required. Regarding radioactive waste generated at nuclear power plants, various disposal options are possible and research results will help select the most suitable option for Kazakhstan.
Nuclear fuel cycle facilities have a multifaceted environmental impact; however, public attention is primarily focused on radiation. In order to evaluate the potential negative radiation impact of the NPP on the environment and regional population during operation, the program will gather information on concentrations of significant radionuclides resulting from past human activities, including global radioactive fallout from nuclear weapons testing, in environmental media, local food products, water and air. Additionally, calculations will be performed on the potential release of radionuclides during normal NPP operation and in abnormal and emergency situations. The background level of chromosomal aberrations will be determined and the population's exposure to radiation will be assessed. This will lay the foundations for a radiation monitoring system in territories and settlements within the NPP's influence zone. This is a prerequisite for ensuring radiation safety and will contribute to the further development of the Republic of Kazakhstan's fuel and energy complex.
The program's objective is to conduct scientific research to support the construction and safe operation of a nuclear power plant in the Republic of Kazakhstan.
Expected outcomes
The following are the direct results:
Under Research Area 1: 'Study of the Nuclear-Physical Characteristics of Promising Power Reactor Designs':
- computational models of the core of a power reactor under consideration for construction in the Republic of Kazakhstan have been developed.
- using these models, the following critical characteristics for reactor startup were calculated: reactivity margin during the first fuel loading, temperature coefficient of reactivity, control system efficiency and power release field at the start of the first campaign.
- based on the results obtained, an analysis was performed of the technical solutions incorporated into the reactor core design.
Under Research Area 2: ‘Management of spent nuclear fuel and radioactive waste’:
- data on the physical parameters of spent nuclear fuel (SNF) during wet and dry storage in the spent fuel pool and on-site storage facility was obtained.
- recommendations were developed for handling and disposing of radioactive waste generated during the operation of nuclear power plants.
- a computational model of the corrosion process was developed and experimental data obtained on the durability of materials used in stabilizing casings under conditions of long-term (up to 100 years) dry storage of spent nuclear fuel.
Under Research Area 3: 'Development of the Framework for a Radiation Monitoring System in the NPP Influence Zone':
- quantitative data on radionuclide concentrations in natural ecosystems (soil, vegetation, animals, the atmosphere and water bodies) was obtained and accumulation factors were calculated.
- quantitative data on radionuclide concentrations characterizing the radiation situation in the settlement were obtained (including radionuclide concentrations in the soil, atmosphere (including indoors), water bodies and agricultural products), and accumulation factors were calculated.
- background chromosomal aberrations in biological specimens were detected and the radiation dose to the population was assessed.
- basic requirements for the organization and conduct of radiation monitoring in the area affected by the nuclear power plant were developed.
Deliverables and effects:
Under Research Area 1: 'Study of the Nuclear-Physical Characteristics of Promising Power Reactor Designs'
A dataset on the nuclear-physical characteristics of promising nuclear power reactor projects will be obtained, along with computational models of core regions including detailed simulations of dimensional and material properties. The results of an analysis of the technical solutions incorporated into the core design will be obtained.
The economic benefits will consist of obtaining new data for analysing the conditions for the effective operation of nuclear power plants with promising reactor designs for construction in the Republic of Kazakhstan.
Environmental benefits will be obtained in the form of results that contribute to the environmentally safe operation of nuclear power plants.
There will also be social benefits in the form of experience gained from conducting complex computational studies, which will provide impetus for developing the Republic of Kazakhstan’s research potential in the field of reactor nuclear physics and developing new scientific areas. This will also contribute to training doctoral and master’s students.
Under Research Area 2: ‘Management of spent nuclear fuel and radioactive waste’
The study will yield the following:
- Data on the characteristics of spent nuclear fuel during dry and wet storage
- Recommendations for selecting technologies for managing radioactive waste from nuclear power plants
- Data for determining the durability of container materials for long-term storage of spent nuclear fuel
It will also assess the economic benefits of selecting the most effective and economically viable methods for managing radioactive waste and spent nuclear fuel generated during the operation of nuclear power plants.
The environmental benefits will consist of developing solutions to minimize radiation exposure from spent nuclear fuel and radioactive waste generated during the operation of nuclear power plants.
The research being conducted will help build public confidence in nuclear energy and contribute to solving the most pressing and socially significant issue facing nuclear power plants: the safe management of radioactive waste.
Under Research Area 3: 'Development of the Framework for a Radiation Monitoring System in the NPP Influence Zone'
The levels of radionuclides in the main components of the natural environment at the site selected for the construction of the nuclear power plant will be determined. Information has been obtained on the distribution of the radionuclides under study in natural ecosystems, as well as on the expected annual effective doses resulting from internal and external radiation exposure for the population living in the vicinity of the nuclear power plant. Recommendations have been developed for setting up a radiation monitoring system in areas and settlements within the NPP’s influence zone.
The economic benefit lies in the scientific development of the environmental monitoring system for the NPP. This will allow clear requirements to be formulated for its structure and composition and help to avoid solutions that lead to redundancy or insufficiency in the future.
The environmental benefits lie in developing scientifically sound requirements to ensure high-quality radiation monitoring. This will enable potential threats to be detected in good time and responded to quickly, thereby reducing radiation exposure to the population and the environment.
The social benefit will be that the developed recommendations for establishing an environmental monitoring system for the NPP will ensure that the regulatory dose limits established in the Republic of Kazakhstan are not exceeded in future, by enabling timely decisions to be made to identify and prevent threats of radiation contamination. Information on the actual radiation situation in the NPP’s impact zone will be made available and transparent.
The implementation of the program will result in:
Publication of twelve articles and/or reviews in peer-reviewed scientific journals in the program's field of study that fall within the first or second quartile by impact factor in the Web of Science database, or with a CiteScore percentile of at least 50 in the Scopus database. Publication of seventeen articles in journals recommended by the Committee for Quality Assurance in Science and Higher Education (Kazakhstan).
Publication of five monographs or textbooks by Kazakhstani publishers.
Acquisition of seven intellectual property rights registered with the National Institute of Intellectual Property of the Republic of Kazakhstan.
Key findings of the Study
The following significant results were achieved during the implementation of the program 'The study to back the building and safe Operation of a Nuclear Power Plant in the Republic of Kazakhstan' in 2023:
Under Research Area 1: 'Study of the Nuclear-Physical Characteristics of Promising Power Reactor Designs'
An analytical review of design solutions for various reactor types was conducted, and the results were used to compile input data for computer modelling of the core regions of the most promising nuclear reactors: water-cooled VVER-1000 and VVER-1200 reactors; BN-600 and BN-800 fast neutron reactors; and the HTGR-30 low-power high-temperature reactor. The designs of the most promising small modular reactors (SMRs) were also examined.
Basic data on the dimensions and material composition of the cores, as well as the parameters of the nuclear fuel used for reactor loading, have been compiled. The physical and neutron-physical properties of the materials used in the cores have been characterised. The amount of data provided enables the modelling of the reactors' cores. The computer model can be detailed to include 3D modelling of the cladding and cores of individual fuel rods, taking into account additional elements such as spacer grids, fuel rod end caps and fuel assemblies.
Data has also been compiled for the subsequent verification of the computer models. This will enable the quality of the modelling to be evaluated based on various neutron-physical parameters. These parameters include reactor reactivity margin, reactivity coefficients and fuel cycle duration, among others.
Under Research Area 2: ‘Management of spent nuclear fuel and radioactive waste’
1) As part of the efforts to manage spent nuclear fuel and radioactive waste, an analytical review was conducted of the options for managing radioactive waste and spent nuclear fuel at operating nuclear power plants (see Appendix G). Data on the possible types of spent nuclear fuel (SNF) and radioactive waste (RAW) for the candidate nuclear reactors at the nuclear power plants (NPPs) in the Republic of Kazakhstan were also compiled. Methods for handling SNF and RAW were studied in relation to Generation III and III+ water-cooled power reactors.
Currently, the most widespread open-type spent fuel storage facility does not reprocess spent nuclear fuel. After interim storage in on-site pools, the fuel is sent for 'dry' storage in special repositories or storage facilities located at the NPP. This storage can last for decades. Following long-term storage, the spent nuclear fuel is intended for final disposal. The Republic of Kazakhstan is currently implementing this approach with regard to SNF from the BN-350 reactor unit. After cooling in an on-site pool, the SNF was packed into casks and placed in an open-air long-term storage facility pending a decision on its final disposal. Due to the absence of facilities in Kazakhstan for reprocessing SNF and the lack of operational deep geological repositories for high-level waste — the construction of which is technically complex and costly, requiring many years of laboratory research — long-term storage is currently the preferred strategy for SNF.
In accordance with generally accepted principles, the management of radioactive waste is regulated by national legislation and international agreements in all countries. After being generated at nuclear power plants, radioactive waste undergoes a series of treatment and disposal processes to reduce hazards and ensure economic viability, before being stored or disposed of in the long term. While the sequence of processes may vary, they almost always include the collection and sorting of waste by category, treatment and volume reduction, conditioning, transportation, and storage or disposal.
Methods for the treatment and conditioning of nuclear power plant waste have now reached a high level of efficiency and reliability , and continue to be improved to enhance the safety and cost-effectiveness of the entire waste management system.
In line with the latest global trends, nuclear power plants are designed with integrated facilities for processing and storing generated radioactive waste, ensuring environmental safety throughout their operational lifetimes. These facilities typically include a sorting area, grinding and compaction units, a liquid radioactive waste ion-selective purification unit, an incineration unit and a cementation unit. They convert all generated radioactive waste into a conditioned state that meets the requirements for long-term storage or disposal. Conditioned radioactive waste storage facilities at nuclear power plants are designed to accommodate the total volume of waste generated during their operational period. This ensures that the waste is stored safely until it is transferred to final disposal sites.
2) The materials used for the stabilizing casings were irradiated in the reactor. These casings serve as the first barrier against the release of radionuclides from spent nuclear fuel in leaking fuel rods.
The 12X18H10T steel selected for the stabilizing casings was used in the packaging of leaking fuel rods from the BN-350 reactor. At this stage of the work:
The irradiated steel samples obtained will be annealed to study the effect of irradiation on the performance characteristics (physical and mechanical properties, and microstructural phase state) of the containment shell material, and to determine its corrosion resistance and service life.
Under Research Area 3: 'Development of the Framework for a Radiation Monitoring System in the NPP Influence Zone'
1) An analysis of long-term data on atmospheric emissions from nuclear power plants has identified the primary radionuclides contributing to total activity. It has been established that the list of monitored radionuclides has expanded over time. For instance, emissions from most NPPs only began to show detectable levels of the radio-ecologically significant radionuclides 14C and 3H after 2018. Test calculations have shown that these radionuclides could account for the majority of the radiation dose received by populations living in regions where NPPs are located. A list of radionuclides to be determined when assessing the 'zero' background of radioactive contamination has been established, including natural (⁴⁰K, ²³⁸U, ²²⁶Ra, ²³²Th, ²²²Rn) and technogenic (⁹⁰Sr, ¹³⁷Cs, ³H, ¹⁴C) radionuclides. Natural ecosystem components that are assessed for their content of these radionuclides include soil, water, air and flora and fauna. An overview of methods for determining the content of these radionuclides in natural ecosystem components has been compiled.
2) A review was conducted of recommendations for determining radiation exposure to the public and personnel of nuclear power plant (NPP) during normal operations or in the event of an accident. The main characteristics, functions, advantages and disadvantages of calculation tools for predicting dose rates to the public via various exposure pathways under normal operating conditions (RESRAD, CROM, PC-CREAM 08®, ESTE Annual Impacts and ROM) and accident scenarios (ESTE, NOSTRADAMUS, RECASS and RODOS) were examined. The criteria used to evaluate the quality and effectiveness of the software tools were identified, including model type, input and output data, supported platforms and licence type. The village of Ulken, the sole administrative unit of the Ulken Rural District in the Zhambyl Region of the Almaty Province, was selected as the settlement from which to form the general sample of the group meeting the study criteria. The method for determining radiation exposure for the population and NPP personnel has been defined as fluorescence in situ hybridisation (FISH), which is a molecular cytogenetic method used to determine the background level of stable chromosomal aberrations in the region where the NPP is planned to be built. The criteria for the questionnaire and informed consent forms for participation in the study have been prepared accordingly.
Based on the results of work conducted in 2023, a monograph titled 'Pulsed Graphite Reactor: Operational Experience and Application for Testing Fuel Rods and Fuel Assemblies”, presents the main characteristics of the IGR reactor and summarises its operational experience and application in supporting research to justify the safety of new nuclear power reactors that could be constructed in Kazakhstan. As part of the research and development work being carried out under this program, studies will also be conducted to substantiate technologies for managing and reprocessing various types of spent nuclear fuel, including those based on research involving highly enriched spent nuclear fuel from the IGR reactor.
Some of these research findings were presented at the 6th International Scientific and Practical Conference, 'Innovative Projects and Technologies in Nuclear Energy', which took place from 14 to 17 November 2023 in Moscow, Russia.