Authors & Affiliations

Ekhlakov I.A., Alekseev P.A.
A.I. Leypunsky Institute for Physics and Power, Obninsk, Russia

Abstract

This paper considers two factors of space radiation that can impact a space reactor safety at its start-up stage. The detailed studies like these are only possible with the use of state-of-the-art calculation software that allows simulation of neutronic processes and specifically reactor physics with a 3-D heterogeneous model of a nuclear power system (NPS). So, the NPS interaction with space radiation was calculated with the use of the GEANT4 software package. First, interaction of ultrarelativistic protons, with the energy up to 100 TeV, with structural materials of the space nuclear power system was studied. The quantitative, spatial and time characteristics of neutron cascades formed and fission rate distributions in the reactor core in probability became available. Based on the data obtained the conclusion was made about an absolute safety of these events for the reactor start-up. Then consideration was given to the effect of solar flare power on the reactor operation. Estimation of the number of fission events in the reactor at the maximum solar flare demonstrated a potential hazard of this factor of space radiation. The analysis of reactor kinetics in the start-up period showed that the level of impact on the nuclear power system operation would be also determined by the proton flux peaking time. The obtained results show that in the course of developing programs for launching spacecraft with a nuclear power system on board and when choosing the time of reactor start-up on the orbit, it is necessary to take into account the effect of powerful solar flares.

Key words
Reactor physics, nuclear power system (NPS), thermionic reactor-converter (TRC), ultrarelativistic heavy charged particle (HCP), neutron flux, accelerated particle flux, neutron cascade

Article Text (PDF, in Russian)

References

UDC 621.039:530.145

Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants", issue 4:4, 2014