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Апсэ, Владимир Александрович

Научные группы

Научная группа

Лаборатория инновационных ядерных реакторов (Кафедра №5)

Организационные подразделения

Организационная единица

Цель ИЯФиТ и стратегия развития - создание и развитие научно-образовательного центра мирового уровня в области ядерной физики и технологий, радиационного материаловедения, физики элементарных частиц, астрофизики и космофизики.

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Апсэ

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Владимир Александрович

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Assessment of the possibility for large-scale 238Pu production in a VVER-1000 power reactor
(2023) Shmelev, A. N.; Geraskin, N. I.; Apse, V. A.; Kulikov, G. G.; Kulikov, E. G.; Glebov, V. B.; Глебов, Василий Борисович; Куликов, Евгений Геннадьевич; Куликов, Геннадий Генрихович; Апсэ, Владимир Александрович; Гераскин, Николай Иванович
The paper presents the estimates for the possibility for large-scale production of 238Pu in the core of a VVER-1000 power reactor. The Np-fraction of minor actinides extracted from transuranic radioactive waste is proposed to be used as the starting material. The irradiation device with NpO2 fuel elements is installed at the reactor core center. The NpO2 fuel lattice pitch is varied and the irradiation device is surrounded by a heavy moderator layer to create the best possible spectral conditions for large-scale production (~ 3 kg/year) of conditioned plutonium with the required isotopic composition (not less than 85% of 238Pu and not more than 2 ppm of 236Pu). Plutonium with such isotopic composition can be used as the thermal source in thermoelectric radioisotope generators and in cardiac pacemakers. It has been demonstrated that the estimated scale of the 238Pu production in a VVER-type power reactor exceeds considerably the existing scale of its production in research reactors.
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Application of small perturbation theory for assessing variations of prompt neutron lifetime in a lead-cooled fast reactor
(2023) Шмелев, А. Н.; Куликов, Геннадий Генрихович; Куликов, Евгений Геннадьевич; Апсэ, Владимир Александрович; Apse, V. A.; Kulikov, G. G.; Kulikov, E. G.
The paper considers the applicability of small perturbation theory to assessing the variations of the prompt neutron lifetime caused by variations in the isotope composition of a lead-cooled fast reactor. The generalized small perturbation theory formulas have been developed to calculate derivatives of the prompt neutron lifetime regarded as a bilinear neutron flux and neutron worth ratio. A numerical algorithm has been proposed for the step-by-step application of the small perturbation theory formulas to assess the prompt neutron lifetime variations caused by a major perturbation in the reactor isotope composition, e.g. by the complete change of the material used earlier as the neutron reflector. The advantage of the proposed approach has been shown which consists in that it is basically possible to determine the role of different neutron reactions, isotopes and energy groups in and their contributions to the total prompt neutron lifetime variation caused by major changes in the reactor isotope composition.
Только метаданные
Safety of a fast reactor with a reflector containing a moderator with heavy atomic weight and weak neutron absorption БЕЗОПАСНОСТЬ БЫСТРОГО РЕАКТОРА С ОТРАЖАТЕЛЕМ, СОДЕРЖАЩИМ ЗАМЕДЛИТЕЛЬ С БОЛЬШИМ АТОМНЫМ ВЕСОМ И МАЛЫМ ПОГЛОЩЕНИЕМ НЕИТРОНОВ
(2019) Kulikov, G. G.; Shmelev, A. N.; Apse, V. A.; Kulikov, E. G.; Куликов, Геннадий Генрихович; Апсэ, Владимир Александрович; Куликов, Евгений Геннадьевич
© 2019 Obninsk Institute for Nuclear Power Engineering, National Research Nuclear University 'MEPhI'. All rights reserved.The purpose of the study is to justify the possibility of improving the safety of fast reactors by surrounding their cores with reflectors made of material with special neutron#physical properties. Such properties of the 208Pb lead isotope as heavy atomic weight, small absorption cross section, and high inelastic scattering threshold lead to some peculiarities in neutron kinetics of the fast reactor with a 208Pb reflector, which can significantly improve the reactor safety. The reflector will also make it possible to generate additional delayed neutrons, which are characterized by «dead» time. This will increase the resistibility of the fission chain reaction to reactivity jumps and exclude prompt supercriticality. Note that the additional delayed neutrons can be generated by the reactor designers. The relevance of the study is that the generation of additional delayed neutrons in the reflector will make it possible to reduce the consequences of a reactivity accident even if the reactivity introduced exceeds the effective fraction of delayed neutrons. At the same time, the role of the fraction of delayed neutrons as the maximum permissible reactivity for reactor safety is depreciated. The scientific novelty of the study is that the problem of the formation of additional neutrons, which in their properties are close to traditional delayed neutrons, has not been posed so far. The authors propose a new method for improving the safety of fast reactors by replenishing the fraction of delayed neutrons due to the time delay of prompt neutrons during their transfer in the reflector. To implement the considered advantages, the following combination is acceptable: lead enriched by 208Pb is used as a neutron reflector while natural lead or other material (sodium, etc.) is used as a coolant in the reactor core.
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The problem of large-scale production of plutonium-238 for autonomous energy sources
(2020) Shmelev, A. N.; Geraskin, N. I.; Kulikov, G. G.; Kulikov, E. G.; Apse, V. A.; Glebov, V. B.; Гераскин, Николай Иванович; Куликов, Геннадий Генрихович; Куликов, Евгений Геннадьевич; Апсэ, Владимир Александрович; Глебов, Василий Борисович
© Published under licence by IOP Publishing Ltd.The article is devoted to the urgent problem of large-scale production of plutonium-238. Various starting isotopes and Pu-238 production schemes are analyzed. The isotope characteristics of the chain based on the starting Np-237 isotope are presented. It has been substantiated that the region of neutron resonant absorption for the isotope Np-237 is the preferred spectrum of its irradiation. It is proposed to form a region with a preferred neutron spectrum in the fast reactor core for irradiation of neptunium-237. The preferred spectrum is achieved by a heterogeneous target structure including neptunium-237 and a moderator with a high atomic weight (Pb, Pb-208, Bi, Pb-Bi eutectic). It is shown that when a moderator with a high atomic weight is used, it becomes possible to form an extensive region with the preferred spectrum. In conclusion, the main conditions for the large-scale production of isotopically pure Pu-238 in a fast reactor are formulated.
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Physical aspects for involvement of thermonuclear reactors into nuclear power systems
(2020) Kulikov, G. G.; Shmelev, A. N.; Apse, V. A.; Kulikov, E. G.; Куликов, Геннадий Генрихович; Апсэ, Владимир Александрович; Куликов, Евгений Геннадьевич
© Published under licence by IOP Publishing Ltd.The paper analyzes a possibility to involve hybrid thermonuclear reactors into the existing nuclear power systems. The possibility is related with production of non-traditional nuclear fuel in thorium blanket of hybrid thermonuclear reactors on D-T plasma. Non-traditional peculiarity of such a fuel consists in significant amounts of some non-traditional isotopes, namely231Pa and232U, together with traditional uranium isotope233U in the fuel. High-energy (14.1 MeV) thermonuclear neutrons can provide accumulation of significant231Pa and232U quantities through threshold (n,2n) and (n,3n) reactions. The promising features of the non-traditional fuel composition for nuclear power thermal reactors, basic component of the existing world-wide nuclear power industry, are defined by the following factors. As is known, 233U is able to provide more economical neutron balance in thermal reactors than235U and reactor-grade plutonium. The better neutron balance can result in higher values of the fuel breeding ratio and, as a consequence, in relaxation of the thermal reactors fuel self-sustainability problem. Isotopes231Pa and232U, being fertile and moderate fissionable nuclides, are able to stabilize time-dependent evolution of the thermal reactors power, prolong the thermal reactors lifetime through higher values of the fuel burn-up. Isotope232U, being intense a-emitter, is able to prevent any attempts for unauthorized usage of233U in nuclear explosive devices, i.e.232U can strengthen regime of nuclear non-proliferation. Thus, the hybrid thermonuclear reactors on D-T plasma with thorium blanket can be involved into nuclear power systems for generation of non-traditional, very promising fuel compositions for traditional nuclear power reactors.
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Possibility assessment for production of non-traditional nuclear fuel in thorium blanket of hybrid thermonuclear reactor
(2020) Kulikov, G. G.; Shmelev, A. N.; Kruglikov, A. E.; Apse, V. A.; Kulikov, E. G.; Куликов, Геннадий Генрихович; Кругликов, Антон Евгеньевич; Апсэ, Владимир Александрович; Куликов, Евгений Геннадьевич
© Published under licence by IOP Publishing Ltd.The paper aims at studying specific peculiarities in isotope composition of thorium blanket under irradiation by fusion neutron source (FNS) in hybrid thermonuclear reactor (HTR). High-energy (14 MeV) component of neutron spectrum in thorium HTR blanket results in production of non-traditional fissile mixture including not only233U, but also231Pa232U and 234U. Extraction of such non-traditional fuel from spent Th-blanket and its utilization in traditional nuclear power reactors could increase fuel burn-up and strengthen regime of nuclear non-proliferation. The detailed investigations of these positive effects require high-precision neutron-physical analyses of thorium HTR blanket. The results obtained in these investigations are presented in the paper. The following results were obtained: the chosen model of HTR allowed us to form high-energy neutron spectrum in Th-blanket with significant fraction of 14 MeV neutrons; it was evaluated that threshold (n,2n) and (n,3n)-reactions are able to produce significant amounts of non-traditional target isotopes231Pa and232U; it was shown that accumulation of non-traditional target isotopes weakened substantially in depth of Th-blanket. So, it seems reasonable to seek for optimal thickness of Th-blanket and, thus, to find optimal loading of natural thorium.
Только метаданные
Proliferation-protected, ultra-high burn-up reactor fuel produced in the thorium blanket of a fusion neutron source
(2020) Kulikov, G. G.; Shmelev, A. N.; Kulikov, E. G.; Apse, V. A.; Куликов, Геннадий Генрихович; Куликов, Евгений Геннадьевич; Апсэ, Владимир Александрович
Copyright © GLOBAL 2019 - International Nuclear Fuel Cycle Conference and TOP FUEL 2019 - Light Water Reactor Fuel Performance Conference.All rights reserved.This paper aims at finding solutions of so important problems of nuclear power as decreasing the scope and the number of technological operations, as well as enhancing the proliferation resistance of fissile materials in nuclear fuel cycle by means of minimal changes in the cycle. The method is including fusion neutron sources with thorium blanket into future nuclear power system. In addition to production of light uranium fraction consisting of 233U and 234U, high-energy 14-MeV neutrons emitted in the process of fusion (D,T)-reaction can generate 231Pa and 232U through (n,2n)- and (n,3n)reactions. It has been demonstrated that admixture of 231Pa into fresh fuel composition can stabilize its neutron-multiplying properties thanks to two well-fissile consecutive isotopes 232U and 233U, products of radiative neutron capture by 231Pa. Coupled system of two well-fissile isotopes can allow us to reach the following goals: the higher fuel burn-up and, as a consequence, the longer fuel lifetime; the shorter scope and the lower number of technological operations in nuclear fuel cycle; the better economic potential of nuclear power technologies.
Только метаданные
On a significant deceleration of the kinetics of fast transient processes in a fast reactor О СУЩЕСТВЕННОМ ЗАМЕДЛЕНИИ КИНЕТИКИ БЫСТРЫХ ПЕРЕХОДНЫХ ПРОЦЕССОВ В ЯДЕРНОМ РЕАКТОРЕ НА БЫСТРЫХ НЕИТРОНАХ
(2020) Kulikov, G. G.; Shmelev, A. N.; Apse, V. A.; Kulikov, E. G.; Апсэ, Владимир Александрович; Куликов, Евгений Геннадьевич
© 2020 Obninsk Institute for Nuclear Power Engineering, National Research Nuclear University 'MEPhI'. All rights reserved.The kinetics of nuclear reactors is determined by the average neutron lifetime. When the inserted reactivity is more than the effective fraction of delayed neutrons, the reactor kinetics becomes very rapid. The fast reactor kinetics can be slowed down by increasing the neutron lifetime. The authors consider the possibility of using a lead isotope, 208Pb, as a neutron reflector with specific properties in the lead-cooled fast reactor. To analyze the emerging effects in a fast reactor, a point kinetics model was selected, which takes into account neutrons returning from the 208Pb reflector to the reactor core. Such specific properties of 208Pb as the high atomic weight and weak neutron absorption allow neutrons from the reactor core to penetrate deeply into 208Pb reflector, slow down in it, and have a noticeable probability to return to the reactor core and affect the chain fission reaction. The neutrons coming back from the 208Pb reflector have a long «dead-time» i.e., the sum of times when neutrons leave the reactor core entering the 208Pb reflector and then diffuse back into the reactor core. During the 'dead-time', these neutrons cannot affect the chain fission reaction. In terms of the delay time, the neutrons returning from the deep layers of the 208Pb reflector are close to the delayed neutrons. Moreover, the number of the neutrons coming back from the 208Pb reflector considerably exceeds the number of the delayed neutrons. As a result, the neutron lifetime formed by the prompt neutron lifetime and the «dead-time» of the neutrons from the 208Pb reflector can be substantially increased. This will lead to a longer reactor runaway period, which will mitigate the effects of prompt supercriticality. Thus, the use of 208Pb as a neutron reflector can significantly improve the safe fast reactor operation.
Только метаданные
Advantages of a Fast Reactor Core Surrounded by a Physically Thick Neutron Reflector Made of Lead-208
(2020) Shmelev, A. N.; Apse, V. A.; Kulikov, G. G.; Kulikov, E. G.; Апсэ, Владимир Александрович; Куликов, Геннадий Генрихович; Куликов, Евгений Геннадьевич
© 2020, Pleiades Publishing, Ltd.Abstract: In the paper, the influence of replacement of natural lead with lead-208 as a coolant and fast reactor reflector on its neutron-physical parameters is considered. The possibility of significantly increasing the mean prompt neutron lifetime by using lead-208 is shown. It is proposed to place a layer containing a neutron absorber over the core in its reflector to control the reactor reactivity. It is shown that when using lead-208, the efficiency of this layer is noticeably higher, and the Doppler effect is enhanced than when using natural lead.
Только метаданные
Favorable Effects of an Inner Lead Cavity on Neutronic Physics of a Lead-Cooled Fast Reactor
(2020) Shmelev, A. N.; Apse, V. A.; Kulikov, G. G.; Kulikov, E. G.; Апсэ, Владимир Александрович; Куликов, Геннадий Генрихович; Куликов, Евгений Геннадьевич
© 2020, Pleiades Publishing, Ltd.Abstract: The paper considers the effects produced by arranging a lead cavity in the central part of a lead-cooled fast reactor core. It is shown that the most favorable effect from the presence of an inner lead cavity at the center of the core can be obtained when radiogenic lead with a dominant 208Pb isotope content is used as the material of the cavity, coolant, and neutron reflector. This is explained by the extremely low neutron absorption of 208Pb in a wide range of neutron energies. If the thickness of the 208Pb inner cavity is chosen properly, then a spectral region with the prevailing share of resonance, epithermal, and thermal neutrons is created in the cavity. This results in a sharp increase in the mean prompt neutron lifetime (by few orders of magnitude) and enhancement of the stabilizing Doppler effect. The neutron migration from the inner cavity to the reactor core is able to intensify the fission chain reaction (FCR) and contribute positively to reactor reactivity. In addition, the high flux of slowed neutrons in the inner 208Pb-cavity makes it possible to expect efficient transmutation of long-lived fission products.