Series: Nuclear and Reactor Constants

since 1971

Русский (РФ)

ISSN 2414-1038 (online)

Authors & Affiliations

Semenov M.Y.1, Mikhailov G.M.1, Peregudov A.A.1, Mishin V.A.1, Dyachenko Y.V.1, Belov S.B.2, Kuznetsov A.E.2, Zheltyshev V.A.3, Lyapin E.P.3, Dubovoy G.Y.3
1 A.I. Leypunsky Institute for Physics and Power Engineering, Obninsk, Russia
2 Afrikantov Experimental Design Bureau for Mechanical Engineering, Nizhny Novgorod, Russia
3 Branch of Rosenergoatom Concern Joint Stock Company “Beloyarsk Nuclear Power Plant”, Zarechnyj, Russia

Semenov M.Yu.1 – Leading Researcher, Cand. Sci. (Phys. and Math.).
Mikhailov G.M.1
– Head of the Laboratory Cand. Sci. (Tech.).
Peregudov A.A.1
– Deputy Director of the NEA for Innovative Development, Cand. Sci. (Tech.).
Mishin V.A.1
– Junior Researcher. Contacts: 1, Sq. Bondarenko, Obninsk, Kaluga Region, 249033. Tel.: +7 (484) 399–85–65; e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it..
Dyachenko Ya.V.1 – Research Engineer of the 1st Category.
Kuznetsov A.E.2
– Leading Research Engineer.
Belov S.B.2
– Head of the Calculation Bureau of the BN Reactor Core Development Department.
Zheltyshev V.A.3 – Head of the Group.
Lyapin E.P.3
– Head of JFL.
Dubovoy G.Yu.3
– Physics Engineer of the 1st Category.


From 2016 to the present day, the BN-800 reactor with a hybrid core is being commercially operated in Russia. During this time, a large amount of experimental data on basic neutron-physical characteristics of the core has been collected. The loading of the hybrid core was permanently changed during the initial time period: different ratio of fuel assemblies with uranium fuel and MOX fuel and also the number of fuel assemblies of medium- and highly-enriched zones. In 2021 the transition to a full core loading with MOX fuel began, which is planned to be completed in 2022. In order to confirm the reasonability of the calculated prediction of neutron-physical characteristics of the BN-800 core, work has been performed to analyze the methods of computational support for the operation of the reactor and to compare the calculated values of the neutron-physical characteristics with the available experimental data.
The calculations were performed using the MMKC code, which implements the Monte-Carlo method, as well as JARFR and GEFEST800 in the diffusion approximation. The comparison of the calculation results for all codes with measurement results allowed to estimate the methodological error in the calculation of the basic neutron-physical characteristics.
Calculations were performed for the first five micro-campaigns of BN-800.
The analysis of the following neutron-physical characteristics was performed:
– The value of the reactivity margin at the beginning and the end of the campaign.
– Values of subcriticality levels during reload and after SR withdrawal.
– Efficiency of single CPS rods and CPS groups.
– Temperature-power effect of reactivity.

BN reactor, BN-800, support code, precision neutron-physical code, Monte-Carlo method, MOX fuel, hybrid core

Article Text (PDF, in Russian)


UDC 621.03

Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants, 2022, issue 1, 1:3