The article evaluates the effect of the cooling water temperature on the pressure in the main condensers of a steam turbine installation C-1200-6.8/50 for nuclear power plants with a VVER-1200 reactor. Based on the results of the study, a simulated thermohydraulic model is created in the dynamic modeling environment of SimInTech technical systems, taking into account the influence of the heat and mass transfer process in the tower evaporative cooling tower and the thermal balance of the turbine condenser. The model makes it possible to quantify the effect of air temperature on the vacuum in the turbine condenser. Based on the data obtained, graphs of the dependence of the pressure in the condenser on the temperature of the main cooling water are constructed, with the help of which it is possible to predict the moment of the onset of operational limits. This assessment is especially relevant for nuclear power plants built in the southern part of central Russia, as well as for foreign projects of Rosatom State Corporation. The experience of operating cooling systems, especially with hard water, shows that compliance with the cleanliness requirements of internal devices is an important measure in maintaining the water-chemical regime and optimizing the operating modes of the cooling tower, therefore, the pollution parameter is introduced in the model description. The objectives of this study are to assess the influence of only external environmental conditions, namely ambient air temperature, without taking into account the process of sediment formation in the system. The practical significance of the work lies in the analysis of operational data to substantiate the need for corrective measures and modernization solutions that can be used by employees of JSC Concern Rosenergoatom Novovoronezh Nuclear Power Plant to improve the efficiency of the circulating water supply system with tower evaporative cooling towers.
During the construction and installation of a nuclear power plant, unavoidable changes are introduced into its design, resulting in differences between the actual physical condition of the constructed NPP and its digital design model. Due to the systemic limitations of traditional documentation methods, which record only those parameters considered significant at the time of acceptance of work, the as-built documentation does not always contain geometric information with the degree of detail required for engineering calculations. Certain engineering tasks arising during commissioning and start-up operations require data on the actual condition of facilities with a level of accuracy and comprehensiveness that is virtually unattainable through traditional visual inspection and manual measurements, but which can be achieved using modern terrestrial laser scanning (TLS) technology. An analysis of TLS application during commissioning works at nuclear power plants and during nuclear facility decommissioning is presented. Based on the experience of work at the backup diesel power plant of power unit No. 3 of the Rostov NPP, at power unit No. 2 of the Belarusian NPP, and during the survey of the main building of Novovoronezh NPP power units, the practical effectiveness of the method for solving specific engineering problems is shown: verification of the actual position of the equipment, justification of earthquake resistance, documentation of the condition of the object at the time of acceptance. A systematic discrepancy between traditional documentation data and the actual condition of installed equipment has been established. It has been established that once a point cloud is created, it is a long-term information asset, applicable both during commissioning and during subsequent operation. Possible directions of application of the TLS technology within the framework of the commissioning work and during the period of industrial operation are shown. The conditions for rational application of TLS, its limitations and prospects for use at Russian-designed NPPs under construction, particularly at Akkuyu NPP, are considered
The relevance of this study is determined by the need to verify radiation monitoring data and to provide an objective assessment of radiation safety of the population residing within the 30-km surveillance zone of the Rostov Nuclear Power Plant (RoNPP). The objective is to analyze interannual dynamics of the radiation situation based on systematic measurements performed during 2021-2025. The study objects include atmospheric fallout, soil, and surface water (the RoNPP cooling pond and Tsimlyansk Reservoir) sampled at control points in Volgodonsk and Tsimlyansk. Gamma spectrometry and radiochemical analysis are applied to determine total β-activity and specific activity of technogenic (¹³⁷Cs, ¹³⁴Cs, ⁶⁰Co, ¹³¹I) and natural (⁴⁰K, ²³²Th, ²²⁶Ra) radionuclides. Statistical processing employs the non-parametric Mann-Kendall test, Sen's slope estimation, correlation analysis (Pearson/Spearman), paired Wilcoxon signed-rank test, and cross-correlation with temporal lags. Average annual values of radionuclide specific activity in atmospheric fallout (∑β, ¹³⁷Cs) consistently remain within background ranges typical for the European part of Russia (43-47% of the upper regional background boundary). ¹³⁷Cs content in soil (1-6 Bq/kg) and water (0.3-0.7 Bq/kg) do not exceed levels attributable to global fallout and is 1–2 orders of magnitude below drinking water standards. Statistical analysis reveals no significant monotonic trends for any monitored parameter (all p > 0.10) and no significant differences between sampling locations. In conclusion, the obtained data indicate the absence of a significant technogenic contribution from the RoNPP to the radiation situation in the surveillance zone. A continuous five-year measurement series is presented with application of modern non-parametric statistical methods for the first time in this region, enabling a transition from descriptive monitoring to quantitative assessment of radiation background stability.
The objective of this work is to develop an approach to analyze transients in nuclear reactors with strong heterogeneities. Currently, reactor plants for small modular reactors (SMRs) are being developed to provide consumers in remote regions with electricity and heat, foster the growth of isolated industrial clusters and territories, and facilitate the development of mineral deposits that require a stable and clean energy source. Advanced reactor designs feature complex configurations of fuel assemblies and cores due to additional control rods and new systems for excess reactivity compensation. This paper investigates a new approach called the surface moments method. The analysis of neutron angular distributions demonstrated that this method holds promise for analyzing systems with strong heterogeneities. The key difference of the surface moments method is a separate description of angular dependencies for two directions (on both sides of the interface) in the form of continuous functions. The theoretical foundations of the surface moments method are outlined. Its accuracy is evaluated against Monte Carlo simulations using model problems. The maximum error in calculating relative fission rates with the surface moments method for the presented problems was 0.6%. This is more than an order of magnitude lower than the maximum error of the diffusion approximation. Thus, the results demonstrate the feasibility of achieving high accuracy within a fraction of a percent and confirm the efficiency of analyzing cores with strong heterogeneities. The presented results give grounds to believe that the surface moments method can be useful for calculations of VVER-S and SMR.
This paper presents a quantitative analysis of occupational injury dynamics and the economic effectiveness of industrial safety measures in the Ulba Metallurgical Plant JSC (UMP JSC) for the period 2020-2024. The study is based on internal corporate reporting data, including the Lost Time Injury Frequency Rate (LTIFR), the number of lost-time injuries, annual expenditures on occupational and industrial safety, and leading indicators reflecting the condition of the safety barrier system. The results show that LTIFR amounted to 0.18 in 2020 and increased to 0.28 in 2021 (the maximum value within the analyzed period), after which it declined to 0.00 and remained at this level throughout 2022-2024. In parallel, total safety expenditures increased from 1,382,325 thousand KZT in 2020 and 1,608,726 thousand KZT in 2021 to 2,102,982 thousand KZT in 2022 and 2,814,728 thousand KZT in 2023, followed by optimization to 1,997,480 thousand KZT in 2024. The data demonstrate a reduction in LTIFR from 0.28 to 0.00 over a four-year interval and its sustained maintenance for three consecutive years. The economic evaluation of risk reduction measures was performed using the Expected Annual Loss (EAL) approach. The present value of costs (PV(C)) is approximately 25 million KZT, while the present value of prevented losses (PV(ΔEAL)) reaches 59 million KZT over a 10-year horizon at a 12% discount rate. The benefit-cost ratio (BCR) exceeded 2.0, indicating a positive net present value of the implemented safety measures. Leading indicators showed significant improvements: coverage of critical control inspections increased from 60% to 90%, training coverage rose from 85% to 97%, the proportion of non-conformities decreased from 18% to 9%, the average time required for corrective actions was reduced by more than half, and near-miss reporting increased from 40 to 80 cases per year. The findings confirm the systemic nature of the achieved effect and demonstrate that the trajectory «increased safety investment – zero LTIFR – expenditure optimization» is consistent with the ALARP principle. Sustained zero LTIFR in 2022-2024 is associated with a combination of engineering, organizational, and behavioral measures and is accompanied by a positive economic return on safety investments.
