Authors & Affiliations

Gurskaya O.S., Dzugkoeva E.M., Korobeynikova L.V., Mishin V.A., Stogov V.Yu.

A.I. Leypunsky Institute for Physics and Power Engineering, Obninsk, Russia

Gurskaya O.S. – Researcher.
Dzugkoeva E.M. – Research Engineer.
Korobeynikova L.V. – Senior Researcher.
Mishin V.A. – Junior Researcher.
Stogov V.Yu. – Senior Researcher. Contacts: 1, pl. Bondarenko, Obninsk, Kaluga region, Russia, 249033. Tel.: +7 (484) 399-50-88; e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it..


The current program in Russia to increase the fuel consumption of fast reactors and increase its burn-out causes the transition to new structural materials, which, in turn, leads to changes in the neutron-physical characteristics of reactors. In particular, the drop in the reactivity reserve noted in the BN-600 reactor of the Beloyarsk NPP at the end of 76 operational cycles, as will be shown below, is due to the transition to a new type of shell steel with an increased content of nickel, which strongly affects the reactivity. Design support for the operation of the BN-600 and BN-800 fast reactors, as well as the experiments carried out on them, is performed by IPPE. This article presents the results of a calculated analysis of the expected changes in the reactivity reserve at the end of 76 operational cycles when replacing the shell steel in BN-600. In addition, the influence of experimental assemblies located in the core on the reactivity reserve of the BN-600 is analyzed. Analysis of calculations of the actual loading of the BN-600 reactor at 76 operational cycle using the methods of the 1st-order perturbation theory, strict perturbation theory, and the Monte Carlo method showed that a partial transition at 76 operational cycle to EK-164 shell steel leads to a decrease in the reactivity margin by 0.030±0.004 %Δk/k. Replacement of steel for the entire core will reduce the reactivity margin by ~0.12 %Δk/k, which is confirmed by Monte Carlo calculations. The calculated reactivity margin ob-tained at the end of 76 operational cycles for the hot state of the BN-600 reactor is in good agreement with the measured reactivity margin.

fast sodium reactor, reactivity reserve, design support, experimental fuel assemblies, shell steel, structural materials

Article Text (PDF, in Russian)


UDC 621.039.51

Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants, 2020, issue 4, 4:9