Diagnostics of the Structure of a Nuclear Power Plant Unit Using Muonography

The Ignalina nuclear power plant (NPP) Units 1 and 2 are Soviet-designed, RBMK (Reaktor Bolshoi Moschnosti Kipyashchiy), channelized, large power-type reactors. The original-design electrical capacity for each unit was 1500 MW. Unit 1 began operating in 1983, and Unit 2 was started up in 1987. In 1994, the government of Lithuania agreed to accept grant support for the Ignalina NPP Safety Improvement Program with funding supplied by the Nuclear Safety Account of the European Bank for Reconstruction and Development (EBRD). As conditions for receiving this funding, the Ignalina NPP agreed to prepare a comprehensive safety analysis report that would undergo independent peer review after it was issued. The EBRD Safety Panel oversaw preparation and review of the report. In 1996, the safety analysis report for Unit 1 was completed and delivered to the EBRD. Part of the analyses covered anticipated transients without scram (ATWS). The analysis showed that some ATWS scenarios could lead to unacceptable consequences in <1 min. The EBRD Safety Panel recommended to the government of Lithuania that the Ignalina NPP develop and implement a program of compensatory measures for the control and protection system before the unit would be allowed to return to operation following its 1998 maintenance outage. A compensatory control and protection system that would mitigate the unacceptable consequences was designed, procured, manufactured, tested, and installed. The project was funded by U.S. Department of Energy.

We describe the methods and present the results of an examination of removable elements of fittings of two power units of the Rovno Nuclear Power Plant after 10 and 13 years of operation. It was discovered that, after the indicated periods of operation, the technical state of these elements was satisfactory and the material of the rods had no serious defects or other types of damage that could restrict the possibility of their subsequent operation. According to the regulations accepted in nuclear power engineering, the operating modes of fittings realized at nuclear power plants are light-duty as far as the number of loading cycles is concerned. Therefore, the degree of local fatigue damage to the metal of the rods does not reach its critical value. The outlined procedure of examination of removable elements of fittings is comprehensive. It is completed by low-cycle fatigue testing of the damaged metal and enables one to perform an adequate analysis of the possibility of subsequent trouble-free operation of the corresponding equipment.

Data on the modern state and development trends for coal and nuclear power engineering in Russia up to 2030 are generalized. It is emphasized that from the viewpoint of strategy, coal and uranium fuel will be the main energy carriers. The forecast of energy consumption is made; the “roadmap” of new power-generating units of heat and nuclear power plants on the territory of Russia is presented.

The particulars of the design of new-generation ASCTP and experience in implementing the system in the No. 3 unit of the Kalininskaya nuclear power plant are examined. The basic requirements and the main approaches for developing ASCTP for the power-generating units of nuclear power plants with newgeneration VVER, including protection from failures for general reasons in the safety control systems, expansion of the functions of the system of the top block level, intellectually signaling, automation level of technological processes, and servicing of the means of automation are presented. It is noted that the principle of optimizing the application of modern information technologies taking account of experience in design and operation of power-generating units with mandatory maintenance of the updated base must play an important role in determining the requirements for and making technical decisions concerning ASCTP for new-generation VVER.

The study is devoted to the selection and justification of circuit solutions for the composition of an intermediate steam super heater using the example of the thermal circuit of the steam turbine unit of the South-Ukraine Nuclear Power Plant (SU NPP).Steam turbine units with water-water power reactors, which are currently in operation and planned for installation in the future, operate on wet steam, therefore measures are taken to dehumidify the steam during its expansion in the turbine unit -intermediate separation and steam superheating according to the following schemes: -separation and two-stage steam superheating; -separation and single-stage steam superheating.Most plants use separation and two-stage intermediate steam superheating.There is no justification for the use of such a scheme in domestic literature.Methodology.A thermal calculation of the steam turbine unit was performed using the method of successive approximations: the productivity of the steam generator was calculated using two-stage and single-stage intermediate steam superheating; a comparative assessment of the mass and size indicators of the separator-steam super heater and the thermal efficiency of the unit was performed.The initial and final parameters of the working fluid and the parameters of the working fluids in the regeneration system correspond to the thermal diagram of the steam turbine unit of a nuclear power plant.Results.A comparison of the technical indicators of two options for using steam intermediate superheating for a steam turbine unit at a nuclear power plant allows conclusions to be drawn about the questionable feasibility of using twostage intermediate steam superheating.Two-stage steam superheating (compared to single-stage) complicates the thermal scheme of the steam turbine unit, the design of the separator-steam superheater, and reduces the productivity of the steam generator (increases the thermal efficiency of the unit) by only 0.28 %.Given the insignificant share of fuel costs for a nuclear power plant, a reduction in total operating costs in the range of hundredths of a percent can be expected.With single-stage intermediate steam superheating, the mass, size, and cost indicators of the steam super heater are improved by reducing the heat transfer surface (by about a third) as a result of increasing the mean logarithmic temperature head by 34 %.Practical significance.The results of the study can be taken into account when selecting and justifying design decisions regarding the composition of steam turbine installations for promising nuclear-fueled steam turbine installations.

One of America’s best kept secrets is the success of its nuclear electric power industry. This paper presents data which support the construction and operating successes enjoyed by energy companies that operate nuclear power plants in the US. The result—the US nuclear industry is alive and well. Perhaps it’s time to start anew the building of nuclear power plants. Let’s take the wraps off the major successes achieved in the nuclear power industry. Over 20% of the electricity generated in the United States comes from nuclear power plants. An adequate, reliable supply of reasonably priced electric energy is not a consequence of an expanding economy and gross national product; it is an absolute necessity before such expansion can occur. It is hard to imagine any aspect of our business or personal lives not, in some way, dependent upon electricity. All over the world (in over 30 countries) nuclear power is a low-cost, secure, safe, dependable, and environmentally friendly form of electric power generation. Nuclear plants in these countries are built in six to eight years using technology developed in the US, with good performance and safety records. This treatise addresses the success experienced by the US nuclear industry over the last 40 years, and makes the case that this reliable, cost-competitive source of electric power can help support the economic engine of the country and help prevent experiences like the recent crises in California and the Northeast. Traditionally, the evaluation of electric power generation facility performance has focused on the ability of plants to produce at design capacity for high percentages of the time. Successful operation of nuclear facilities is determined by examining capacity or load factors. Load factor is the percentage of design generating capacity that a power plant actually produces over the course of a year’s operation. This paper makes the case that these operating performance indicators warrant renewed consideration of the nuclear option. Usage of electricity in the US now approaches total generating capacity. The Nuclear Regulatory Commission has pre-approved construction and operating licenses for several nuclear plant designs. State public service commissions are beginning to understand that dramatic reform is required. The economy is recovering and inflation is minimal. It’s time, once more, to turn to the safe, reliable, environmentally friendly nuclear power alternative.

The full-scale simulator (FSS) of nuclear power plant (NPP) unit is designed for operating personnel professional joint training of the power unit's main control room using its real full-scale model. Testing of all FSS systems has an important place in the software part of the development of FSS. Currently, the development of software testing for FSS systems is required. The article provides an overview ozf modern testing systems. In addition, the article presents the algorithms for the operation of tests designed by using Pytest – the framework for writing software tests. The paper presents the following tests: overpower test and check for the presence of chugging; test of the correctness of the decay heat model in terms of amplitude in the event of scram and stable attenuation of decay heat after scram.

The WWER-1000 reactor is operated at 13 of the 15 operating power units of Ukraine's nuclear power plants (NPPs). Ensuring long-term and safe operation of such reactors is the basis for reliable operation of all 13 Ukrainian nuclear power plants units and the guarantor of Ukraine's energy security. The determining and leading factor influencing the safety and proper residual life of the WWER-1000 reactor vessel is the radiation embrittlement of the reactor steel. The consequences of radiation embrittlement of reactor steel are negatively manifested in emergencies with cooling of the core. This process itself – radiation embrittlement – accumulates constantly and gradually. Therefore, it is important to monitor it by periodically performing ongoing rapid assessments of the brittle strength of the WWER-1000 reactor vessel (along with other factors, including cyclic damage, as discussed in a previous publication). Therefore, it is important to use the calculated express methods of periodic assessment of the brittle strength of the WWER-1000 reactor vessel with guaranteed accuracy. The effectiveness of the approach is supported by low cost of resources – engineering staff, fast and relatively simplified use of computers and software. As an example and confirmation of the applicability of the proposed approach, an expert rapid assessment of the fragile strength and residual life of the reactor vessel of Unit № 1 of the South-Ukrainian Nuclear Power Plant was performed. This takes into account the actual, passport characteristics of its metal. The negative impact of the rigid regime with cooling of the WWER-1000 reactor of Unit № 1, not taken into account by the operating organization (South-Ukrainian Nuclear Power Plant) when extending its designated resource / service life, is shown. timely to clarify complex factors, technical aspects and parameters, as well as – their possible negative effects on the safe operation of systems and elements of nuclear power plants.

A nuclear power plant is a complex technological facility. The introduction of new standards and experience gained in the operation of domestic and foreign nuclear power plants requires the introduction of changes in the operating organization of existing nuclear power plants and improvements in their equipment. A general survey of the modernization of existing nuclear power plants with RBMK-1000 type reactors is presented. Measures for modernization of the power-generating units of nuclear power plants carried out following the accident at the Chernobyl nuclear power plant and at the present time are discussed. Because of modernization, the safety, reliability and economic efficiency of nuclear power plants have improved. The principal focus is on modernization of the reactor plant.

Recently, interest in nuclear power has surged. Several countries are either planning for or have already begun constructing new nuclear power plants. The European Union now includes nuclear in its green taxonomy (EU 2022/1214). Coupled with recent technical development, most notably 4th generation- and Small Modular Reactor technology, there are even talks of a renaissance of nuclear power.In Sweden, this phenomenon has manifested in plans to again build nuclear power plants. The government has launched a new nuclear program (Busch et al, 2023), laws are being changed (Andersson, 2023) and investigations are ongoing to facilitate the financing of new power plants (Dillén, 2024).In the past, Sweden was at the forefront of civil nuclear technology by building twelve reactors between 1971 and 1985 (IAEA, 2021). Thereafter followed, however, a period of decommissioning where six reactors were phased out (ibid, 2021). With recent plans to build new nuclear plants, Sweden has once again changed paths.According to theoretical insights of sociotechnical imaginaries (STI) this development can be understood as informed by visions of how nuclear power will aid in achieving a beneficial future (Jasanoff &amp; Kim, 2015; 2009). Within this field of research, several papers have studied different nations’ constructions of (un)desirable futures of nuclear power (e.g., Felt, 2015; Jasanoff &amp; Kim, 2009). Hence, an approach informed by STIs is adopted to study the Swedish turn towards building new nuclear power.Interestingly, many of the arguments for new nuclear power in Sweden evoke its history. Sweden is described as a pioneer in nuclear energy with extensive experience and a high level of skills in science and engineering. This act of evoking the past to describe the future highlights the complex temporalities involved in the establishment of STIs. Past experiences are recalled in the present and used to inform how the future is envisioned (c.f. nuclear memory, Keating &amp; Storm, 2023), hence, creating an intrinsic entanglement of temporalities partly studied (e.g., Samimian-Darash et al, 2024), but more research into this entanglement is needed.Furthermore, as suggested by Hughes (2024), previous studies have not considered enough the extent to which emotions and affect aid in the forming of STIs. Due to the discursive nature of STIs they tend to be studied through policy documents, thus missing the embodied feelings involved in their enactment (ibid, 2024). Therefore, this study mainly relies on interviews with prominent individuals and experts in nuclear power (N=39), in addition to the analysis of newspapers and other written documentation.The result highlights how the evocation of nostalgia is central to the Swedish turn towards new nuclear power. Hence, also showing how the formulation of the STI is equally concerned with envisioning the past as with envisioning the future. The paper contributes to the general research on STIs, especially ongoing discussions on its intertwined temporalities and affective and emotional dimensions, as well as providing empirical insights on new nuclear power in Sweden.

The access to reliable sources of energy is the key to sustainable development of mankind. The major part of the energy consumed by people is generated with a chemical reaction of fossil fuel burning. This leads to quick depletion of natural resources and progressing environmental pollution. The contribution of the renewable energy sources to the general energy production remains insignificant. A modern 1,000 MW coal-fired thermal power plant (TPP) burns 2.5 million tons of coal per year and produces significant amount of solid and gaseous waste. TPPs are the largest consumers of atmospheric oxygen and sources of carbon dioxide. A nuclear power plant (NPP) of the same power consumes less than 50 tons of fuel per year. Environmentally significant NPP’s waste (liquid, solid and gaseous) is carefully collected, reduced in volume (evaporation, filtering, compaction, incineration, etc.) and securely isolated from the environment at the plant. The annual volume of waste for storage is less than 100 m3. The waste is under the control of a special NPP’s service and regulatory authorities. The energy of fission reaction millions of times exceeding the energy of burning has an enormous potential that mankind can receive. Four hundred and thirty-three nuclear power units with a total capacity of about 400 GW exist in the world. The accident at the Fukushima Daiichi NPP in Japan in March 2011 caused anxiety about nuclear safety throughout the world and raised questions about the future of nuclear power. Now, it is clear that the use of nuclear power will continue to grow in the coming decades, although the growth will be slower than was anticipated before the accident. Many countries with existing nuclear power programmes plan to expand them. Many new countries, both developed and developing, plan to introduce nuclear power. Some countries, such as Germany, plan to abandon nuclear energy. The IAEA’s latest projections show a steady rise in the number of NPPs in the world in the next 20 years. They project a growth in nuclear power capacity by 23% by 2030 in the low projection and by 100% in the high projection [1,2]. The basis of modern nuclear power comprises water-cooled nuclear reactors which use the energy potential of natural uranium inefficiently (thermal reactors). The thermal reactors use isotope U-235 in which the content of natural uranium is &lt;1%. Breeder reactors are capable of using the significant part of energy potential, which is unavailable to thermal light water reactors. As a result, the same starting quantity of uranium can produce 50 times more energy. These reactors can transform U-238 into fissile Pu-239 in larger amounts than they consume fissile material. This feature is called ‘breeding’ [3]. The key problem of using the basic benefitsv of nuclear power is to ensure the safety of its use, as well as decommissioning and reliable isolation of process waste from the biosphere. The long-term large-scale nuclear power should possess guaranteed safety, economic stability and competitiveness, absence of the raw material base restrictions for a long period of time and environmental sustainability (low waste). The nuclear power systems with fast neutron reactors and liquid metal coolant can satisfy these conditions. More than 40 years of Russian experience in the field of construction and operation of sodium fast reactors makes it possible to summarize and analyze the ecological features of reactors of this type, the possibility of their use for sustainable energy supply of mankind and solving environmental problems.

An algorithm for creating the electrical part of an energy complex consisting of power units of a low-power nuclear power plant and a hydroelectric power plant (HPP) has been developed. As an example, the results of various options for the development of an energy complex, suiting Kenya conditions, are presented: a low power nuclear plant having two power units with modular SVBR-100 reactors and a liquid-metal coolant-lead-bismuth alloy-of 100 MW, the creation of which is completed by the Russian State Nuclear Energy Corporation Rosatom, and a hydro power plant having two hydro-generators each with a capacity of 30 MW. As a result of the project implementation, the parameters and types of the main equipment of the energy complex (generators, transformers, hydro turbines) have been determined, the options for the power output scheme of the energy complex and schemes of the auxiliaries have also been proposed. The calculation of short-circuit currents has been performed and the types and parameters of the necessary modern electro-technical equipment for the energy blocks have been determined. The possibility of creating promising energy complexes with hydro and nuclear power plants with low-power nuclear reactors has been justified.

The dynamic rod worth measurement method, which is used widely for PWR with square geometry lattices, is applied on WWER type reactor with hexagonal geometry lattices. RTNP code is developed to calculate the static spatial factors (SSF) and the dynamic spatial factors (DSF) through simulating the 3D space-time neutron dynamics and the response of excore detector during the measurement process. The improved quasi-static method is used for temporal discretization. The time-dependent shape equation is then transferred to a fixed source problem through backward Euler formula. And Multi-group Monte Carlo method is used to solve this fixed source problem. Four tests on Tianwan nuclear power plant (NPP) units 1&amp;2 have been done since 2015. The measured results agree well with the predicted values. It takes about half hour per bank and 5 hours to measure all banks worth. The conventional boron dilution was used for rod worth measurement of Tianwan NPP units 1&amp;2. It took at least 2 hours per bank and produced lots of boron wastes. The boron dilution has been replaced with this method for Tianwan NPP units 1&amp;2.

High requirements are imposed on economic efficiency of nuclear power plant units operation. Obvious way of increasing&#x0D; economic benefit of nuclear power plant units operation is increasing the amount of generated electricity. The article&#x0D; describes a method of increasing economic benefit of nuclear power plant units by shortening its downtime due to&#x0D; scheduled maintenance and repair. As safety assurance is the top priority during nuclear power plant units operation,&#x0D; increase of economic viability of nuclear power plant units should be carried out with this consideration, which is the&#x0D; distinctive feature of the proposed method.

The most important results of the scientific and scientific-organizational activities of the Institute for Safety Problems of Nuclear Power Plants of the National Academy of Sciences of Ukraine in 2023 are presented. Even under the conditions of a large-scale invasion of Russian troops on the territory of Ukraine and the continuation of hostilities by the Russian aggressor, the employees of the Institute completed all the planned tasks, which primarily became possible due to the introduction of a number of organizational measures, the effectiveness of which is confirmed by a significant increase in the quality of scientific results, their implementation, as well as the publication activity of researchers. Over the years of eliminating the consequences of the Chornobyl nuclear power plant accident, performing scientific research at the Shelter object and in the Chornobyl Exclusion Zone, a unique experience has been accumulated that allows us to solve complex tasks of ensuring the appropriate level of nuclear, radiation and environmental safety of the energy industry of Ukraine and facilities, which use nuclear technologies. The results of the Institute’s research work are implemented in practical activities at power units of nuclear power plants of Ukraine, during the scientific and technical support of works on the Shelter object transformation into an ecologically safe system and the construction of the Centralized Spent Nuclear Fuel Storage Facility. The importance of the Institute in solving topical and strategically important scientific and technical tasks in the war and post-war periods has been approved by the management of the National Academy of Sciences of Ukraine, experts in evaluating the effectiveness of its activities, as well as international partners. All this indicates the possibility of further development and, if necessary, the expansion of the scope of complex tasks, which are solved by specialists of the Institute.