Testing System Development for Full-Scale Simulators of Nuclear Power Plant Unit

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 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.

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.

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.

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.

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.

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.

Main control room (MCR) is an important site of the nuclear power plant (NPP), and the environmental condition in MCR shall be benefit to operators performing their task effectively and comfortably. With the development of HFE (human factor engineering), there is more attention to environment design of MCR. the MCR environment design mainly include noise reduction, illumination, air condition, interior and colour design, earthquake protection, fire protection, radiation protection, missile protection, and so on. At present, the indexes for environment design of domestic and international regulations and standards are inconsistent. None of regulations and standards is comprehensive, detailed and fully adapting to the MCR environment design of NPP, and some indexes are difficult to achieve. This paper compares the indexes of MCR environment of regulations and standards, performs HFE study about the indexes of MCR environment design combining with engineering experience in different NPPs. Finally, this paper proposes a set of environment design indexes applied to MCR of NPP, which will guide the MCR environment design of third generation NPPs.

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 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.

The simple graphic method proposed for assessment of the operational safety of operating power-generating units of nuclear power plants makes it possible to:

Examination of VVER-440 RPV steel re-irradiation behavior using materials from operating units

The principles for constructing a problem-oriented system for designing a technology for disassembling the equipment in the power-generating units of nuclear power plants which are being decommissioned, starting from the rules of organization and use of the design space on the basis of informational and expert methods and taking account of the influence factors of the environment where the technology functions, are presented. 2 figures, 10 references.

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.

This study intended to explore the effects of personal characteristics (measured by Cattell's 16 Personality Factors), time pressure and interface design on task performance in an Emergency Operating Procedure (EOP) task that required judgment in a simulated Nuclear Power Plant (NPP) condition. The performance criteria included judgment time, error rate, situation awareness, and subjective workload, under different interfaces (ecological /traditional) and time pressure levels (high/low). The analysis of variance showed significant influence of time pressure. And by developing regression models for personality factors under each interface style, significant relationships between personality traits (privateness, openness to change, perfectionism, rule-consciousness, and social boldness) and human performance were found.