Physics of Atomic Nuclei最新文献

{"title":"Determination of the Characteristics of Neutron Field of the IGRIK-2 Reactor Using the Neutron Activation Method","authors":"A. R. Baphaev,&nbsp;V. I. Litvin,&nbsp;A. A. Kuzinskaya,&nbsp;L. S. Ershova","doi":"10.1134/S1063778824080015","DOIUrl":"10.1134/S1063778824080015","url":null,"abstract":"<p>The energy spectra of neutrons in the experimental channel, in the window, and behind the biological shielding of the core of the IGRIK-2 pulse nuclear reactor was measured using the neutron activation method. Approximately 15 neutron activation detectors were employed. The neutron spectrum reconstruction was performed using the method of directed divergence minimization. A comparison of the main integral characteristics of the neutron field with numerical Monte Carlo calculations is presented.</p>","PeriodicalId":728,"journal":{"name":"Physics of Atomic Nuclei","volume":"87 8","pages":"1073 - 1077"},"PeriodicalIF":0.3,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142963016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Machine Learning Method for Validation of the Computational Model of Nonstationary Xenon Processes in the VVER Reactor Based on the Algorithm of Separation of Variables","authors":"A. L. Nikolaev,&nbsp;M. A. Uvakin,&nbsp;M. V. Antipov,&nbsp;I. V. Makhin,&nbsp;G. A. Ryabov","doi":"10.1134/S1063778824080210","DOIUrl":"10.1134/S1063778824080210","url":null,"abstract":"<p>In the paper, we present a method for validating the KORSAR/GP software package in terms of a mathematical model of nonstationary xenon processes in a VVER reactor that is based on the separation of spatial and temporal variables. The data obtained from various high-power VVER installations in experiments to study the spatial distribution of energy release under nonstationary reactor poisoning conditions caused by the action of various regulators are used. The model is based on the classification of means of affecting reactivity by the type of variable in energy release, which undergoes changes significant for the process as a result of this impact. Nonstationary xenon poisoning processes, which involve control rods of the control and protection systems and water exchange operations with a change in the concentration of boric acid, as well as both of the listed methods, both in the presence of a change in the neutron power of the reactor and when maintaining its constant value, are considered. A machine learning method on the basis of regression analysis making it possible to estimate the error in calculating the parameters of the energy release field under conditions of spatial, temporal, and spatiotemporal feedback of the xenon concentration and regulators is developed. On the basis of the processed experimental data, a training array, which is used for machine learning of this model, is formed. As a result of the developed algorithm, an error estimate for the model of the computing code with allowance for the partial impact of various means of changing the reactivity in a given calculation is made.</p>","PeriodicalId":728,"journal":{"name":"Physics of Atomic Nuclei","volume":"87 8","pages":"1030 - 1038"},"PeriodicalIF":0.3,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142963078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical Simulation of Fluid Flow and Heat Transfer at Supercritical Pressures of Water Coolant for a Wire-Wrapped Rod Bundle","authors":"V. Yu. Kukanov,&nbsp;A.A. Sedov,&nbsp;P. S. Polyakov","doi":"10.1134/S1063778824080209","DOIUrl":"10.1134/S1063778824080209","url":null,"abstract":"<p>In this work, to assess the efficiency of the ANSYS CFX 14.0 code and obtain fluid flow properties, one heat transfer experiment using water as a coolant at supercritical pressures was selected: a 2 × 2 rod bundle with wire spacers along its length. A 3D CFD study of fluid flow and heat transfer at supercritical pressures was conducted for the geometry of the rod bundle, with the key parameter being the temperature of the inner wall of the fuel rod simulator. The influence of turbulence models SST, <i>k</i>–ω, and BSL, as well as various types of computational mesh to ensure the reliability of the assumed wall temperature, was investigated. After the study, the CFD model data was verified against experimental data. It was found that the CFD model was able to qualitatively describe the temperatures of the inner surfaces of the rods as reported in the experiments.</p>","PeriodicalId":728,"journal":{"name":"Physics of Atomic Nuclei","volume":"87 8","pages":"1123 - 1137"},"PeriodicalIF":0.3,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142963021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimation of Filamentary Transport Parameters at the Edge of Tokamak MEPhIST-0","authors":"A. A. Stepanenko,&nbsp;S. A. Krat","doi":"10.1134/S1063778824070123","DOIUrl":"10.1134/S1063778824070123","url":null,"abstract":"<p>The parameters of the convective filamentary transport in the edge region of the small spherical tokamak MEPhIST-0 are estimated. To describe dynamics of the installation scrape-off-layer plasma, an electromagnetic two-fluid MHD model was employed. The operational parameters of the tokamak and their impact on the characteristics of turbulent plasma transport are discussed. Using the BOUT++ code, dynamics of isolated filaments were simulated under conditions corresponding to the edge region of the tokamak in various discharge scenarios. It is shown that, despite the compactness of the machine, it may be possible to create and study both electrostatic and electromagnetic regimes of anomalous edge plasma transport in the installation.</p>","PeriodicalId":728,"journal":{"name":"Physics of Atomic Nuclei","volume":"87 7","pages":"902 - 910"},"PeriodicalIF":0.3,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142941039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Radiation Exposure on Optics in ITER","authors":"K. Yu. Vukolov,&nbsp;E. N. Andreenko,&nbsp;R. S. Afanasenko,&nbsp;I. I. Orlovskiy,&nbsp;R. N. Rodionov","doi":"10.1134/S1063778824070160","DOIUrl":"10.1134/S1063778824070160","url":null,"abstract":"<p>The problems related to the effect of radiation exposure on the transmission optics used in diagnostic systems of the International Thermonuclear Experimental Reactor (ITER) are considered. These problems are discussed using the example of H-alpha and Visible Spectroscopy (HA&amp;VS) in the equatorial port 11 of the ITER. Using neutron calculations based on the Monte Carlo method, radiation conditions for diagnostic components in the equatorial port, including the port cell area, are determined. A brief review of radiation effects and radiation tests of optical materials is presented. On the basis of the results of these tests and data on the radiation environment, the optical performance of the visible spectroscopy diagnostic components at the end of ITER lifetime is assessed.</p>","PeriodicalId":728,"journal":{"name":"Physics of Atomic Nuclei","volume":"87 7","pages":"829 - 847"},"PeriodicalIF":0.3,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142941092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advances in the Physical Start-Up Test Program for VVER-1200 Power Units","authors":"S. V. Tsyganov,&nbsp;Yu. A. Kraynov,&nbsp;A. A. Gribov","doi":"10.1134/S1063778824080234","DOIUrl":"10.1134/S1063778824080234","url":null,"abstract":"<p>Unit 1 of the Novovoronezh NPP-2 operating the first VVER-1200 reactor of the 3+ generation reached a critical state for the first time in May 2016, and the physical start-up of the power unit was carried out. The National Research Center Kurchatov Institute was the scientific supervisor of the start-up of the first-of-a-kind unit with the VVER-1200 reactor at the Novovoronezh NPP-2 and power units of the Belarusian NPP. By now, five VVER-1200 units have been commissioned. The experience gained during the preparation and conduct of physical tests at the first units was used during the start-up of the next ones. Specific features of the preparation and implementation of the program of physical tests at VVER-1200 units, which were developed and implemented by specialists of the National Research Center Kurchatov Institute, are presented.</p>","PeriodicalId":728,"journal":{"name":"Physics of Atomic Nuclei","volume":"87 8","pages":"1039 - 1046"},"PeriodicalIF":0.3,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142963081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental Study of the Gamma Component in the Rhodium SPD Signal","authors":"V. N. Kochkin,&nbsp;A. Yu. Kurchenkov,&nbsp;E. N. Poznyrev,&nbsp;Yu. M. Semchenkov","doi":"10.1134/S1063778824080064","DOIUrl":"10.1134/S1063778824080064","url":null,"abstract":"<p>A primary comprehensive experimental study of the contribution of reactor gamma radiation to the total signal of an SPD with a rhodium emitter was performed. This contribution was assessed by comparing the signals of a rhodium SPD and the same SPD with a palladium emitter, since palladium has similar electron-photonic properties to rhodium, but it lacks the beta decay of neutron activation products, which is the main component of the useful signal of a rhodium SPD. Primary tests comparing the signals of two SPD were carried out at the IR-8 research reactor. To confirm the assumption that the electron-photon properties of rhodium and palladium SPD are similar, special measurements were performed on the GUT200m gamma installation.</p>","PeriodicalId":728,"journal":{"name":"Physics of Atomic Nuclei","volume":"87 8","pages":"1060 - 1063"},"PeriodicalIF":0.3,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142963082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Methodology for Calculating the Hydrogen Isotope Inventory in Tritium Fuel Cycle Systems of the DEMO-FNS Tokamak","authors":"S. S. Ananyev,&nbsp;B. V. Ivanov","doi":"10.1134/S1063778824070019","DOIUrl":"10.1134/S1063778824070019","url":null,"abstract":"<p>The applied technologies for handling tritium and the efficiency of its use in the fuel cycle of a fusion facility affect the start-up tritium inventory, the possibility of tritium self-sufficiency, etc. These parameters largely determine the cost of the facility, its efficiency, and safety during operation. Formation of the conceptual configuration of the fuel cycle, calculation of the tritium inventory in its systems, and determination of the scope for further development are important problems in facility design. In order to calculate the flows of fuel components and tritium inventory in the fuel cycle (FC) of a tokamak-based fusion neutron source, the FC-FNS code developed at the Kurchatov Institute has been used since 2013. It implements the possibility of calculating the number of hydrogen isotopes contained in different FC systems. The article describes the current state of research on modeling the flow of fuel components in FC systems of the tokamak with a tritium-breeding blanket, presents simplified schemes of FC systems, and describes the principles of their operation and the methodology for calculating the inventory of hydrogen isotopes in them. It is substantiated that the number of fuel components in the facility will be primarily determined by fuel cycle technologies, which, in turn, depend on plasma parameters and scenarios of facility operation. It is shown that, for the DEMO-FNS project with a fusion power of 40 MW, which corresponds to the combustion of 7 × 10^–5 g/s of tritium, the startup tritium inventory will be 400–430 g with a circulating fuel flow through the facility chamber of up to 0.1 g/s. Increasing fuel flows through the injection, hydrogen isotope separation, and some other DEMO-FNS systems, if convective edge-localized modes (ELMs) are taken into account, will lead to an increase in the operational tritium inventory in the fuel cycle up to 500 g. If there is a tritium-breeding blanket in the facility, tritium inventory in it (including the long-term storage) will be no more than 800 g.</p>","PeriodicalId":728,"journal":{"name":"Physics of Atomic Nuclei","volume":"87 7","pages":"958 - 978"},"PeriodicalIF":0.3,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142941040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"About Current-Carrying Capacity of Superconductors with Smoothed Current–Voltage Characteristic","authors":"V. R. Romanovskii","doi":"10.1134/S106377882407010X","DOIUrl":"10.1134/S106377882407010X","url":null,"abstract":"<p>The physical characteristics of stable formation of the limiting permissible thermo-electrodynamic states of superconductors with various types of nonlinearity in their current–voltage characteristics (CVC) are discussed. The analysis was based on describing the CVC using a model that assumes its continuous increase with varying degrees of smoothing (different intensities of increase at a fixed value of the critical current). A power-law equation was used to describe it. The results were compared with those from numerical experiments simulating thermo-electrodynamic states of superconductors with a zero-voltage subcritical region and an idealized CVC (nonsmoothed CVC), described by a piecewise continuous equation derived from the viscous flux-flow model. It is shown that an increase in the smoothing of the CVC of a superconductor, under otherwise equal conditions (at a fixed value of critical current density and cooling conditions), is accompanied by a decrease in its current-carrying capacity. Its degradation is caused by a corresponding increase in heat losses, which inevitably exist owing to the continuous increase in the CVC of the superconductor throughout the current injection process. As a consequence, the values of the limiting permissible currents stably flowing through the superconductor with a nonsmoothed CVC, under otherwise equal conditions, are higher than the corresponding values calculated for superconductors with a smoothed CVC. This feature is observed despite the different nature of current filling the cross section of the superconductor. It is proven that, for the correct determination of the current-carrying capacity of superconductors, the permissible values of temperature and electric field intensity preceding the onset of current instability cannot be predefined. They depend on the degree of smoothing of the CVC, the current injection rate, the transverse size of the superconductor, and the conditions of cooling. As a consequence, there is a nontrivial relationship between the maximum allowable losses and the maximum stable value of injected current. These features must be taken into account when experimentally measuring the CVCs of superconductors and their current-carrying capacity.</p>","PeriodicalId":728,"journal":{"name":"Physics of Atomic Nuclei","volume":"87 7","pages":"918 - 926"},"PeriodicalIF":0.3,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142941068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tritium Fuel Cycle Technology Readiness Assessment for the DEMO-FNS Reactor. Part 2","authors":"B. V. Ivanov,&nbsp;S. S. Ananiev","doi":"10.1134/S1063778824070056","DOIUrl":"10.1134/S1063778824070056","url":null,"abstract":"<p>DEMO-FNS is a 40 MW tokamak-based hybrid (fusion–fission) facility being designed in Russia. To date, the architecture of the tritium fuel cycle (FC) has been formed, and the requirements for the main technological systems have been determined. The parameters of the FC systems have been obtained using the FC-FNS electronic code developed by the project team. In order to create the DEMO-FNS facility, it is necessary to determine the current level of development of FC technologies to assess the possibility of their application. The article continues the analysis of readiness of FC technologies of the DEMO-FNS facility in Russia started by the authors earlier. For the analysis, the technology readiness level (TRL) methodology is used, according to which technologies in the target application area correspond to different readiness levels from TRL1 (basic principles observed and reported) to TRL9 (technology is verified by successful operation in the target application area). The following technologies are considered in the article: pellet injection, neutral beam injection, gas injection, tritium breeding in the blanket, tritium extraction from the blanket, and sorption storage of hydrogen isotopes (HIs). It is shown that in Russia there is a significant potential (TRL4) in the field of technologies necessary for tritium breeding in the DEMO-FNS blanket, but at present the work is frozen. Injection technologies, especially pellet injection, are world-class (TRL4–5). HI sorption storage technologies are highly developed (TRL5–6) and are used in complex processes with large amounts of tritium. The readiness level of the listed technologies is insufficient for application in the FC of the DEMO-FNS facility. It is necessary to increase the level of readiness within research and development programs, to create specialized stands for testing and demonstration of technologies, and to create experimental fusion facilities for testing and integration of technologies.</p>","PeriodicalId":728,"journal":{"name":"Physics of Atomic Nuclei","volume":"87 7","pages":"979 - 992"},"PeriodicalIF":0.3,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142941225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}