Izvestiya vuzov. Yadernaya Energetika

The peer-reviewed scientific and technology journal. ISSN: 0204-3327

Minimizing Reactivity Margin of BN-1200 Reactor: Feasibility and Expediency

9/17/2026 2026 - #03 Current issues in nuclear energy

Vasilyev B.A. Bogdanova E.V. Kiselev A.V.

DOI: https://doi.org/10.26583/npe.2026.3.01

UDC: 621.039.51

The problem of minimizing the reactivity margin of a large fast reactor (BN-1200 type) is discussed. It is noted that minimizing the reactivity margin essentially boils down to minimizing the loss of reactivity during fuel burnup. Technical solutions are presented that provided a decrease in the reactivity margin during fuel burnup in the BN-1200 reactor design compared to this parameter in BN-600 and BN-800 reactors. In addition, methods are considered to reduce the loss of reactivity during fuel burnup and minimize the reactivity margin. It is estimated that, given the uncertainties in assessing the reactivity margin in BN-600 and BN-800 reactors, the minimum reactivity margin for fuel burnup in a BN-1200 reactor can be about 0.3% Δk/k, and the minimum reactivity margin that must be taken into account in reactor safety analyses should be taken at 0.5% Δk/k. An analysis of the effectiveness for achieving the minimum possible reactivity margin was performed, which showed a relatively small significance of the possible in practice minimization of the reactivity margin for the reactor safety indicators and a large significance of the economic minimization in the event of a significant initial reactivity margin.

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BN reactor MOX fuel MNUP fuel breeding ration of the core reactivity margin fuel burnup minimization of reactivity loss safety efficiency

Link for citing the article: Vasilyev B.A., Bogdanova E.V., Kiselev A.V. Minimizing Reactivity Margin of BN-1200 Reactor: Feasibility and Expediency. Izvestiya vuzov. Yadernaya Energetika. 2026, no. 3, pp. 7-26; DOI: https://doi.org/10.26583/npe.2026.3.01 (in Russian).

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