Computational Analysis of the Possible Location of Ionization Chambers in Fast Reactors.

Algorithms and codes were developed that facilitate the selection of the locations of ionization chambers detecting variations in reactor power. For each time step, the nonstationary neutron transport equation is solved, and the reactivity changes are found using the inverse solution of the kinetics equation in the point approximation. At each step, a set of the best points for moment in time is determined where the reactivity deviations from the reference results are minimal. At the end of the entire calculation, such points with maximum total occurrence are selected. Then the version of the location of ionization chambers selected taking design constraints into consideration is applied to explore various scenarios of motion of control rods. The study is based on the assumption that the equations of point kinetics are used in the processing of ionization chamber readings at an operating NPP. The factors that limit the use of this methodology are the inapplicability of point kinetics at high reactivity values and the potential infeasibility of reconciling the contradictory results obtained in modeling various scenarios of control rod motion. Compromise decisions should be made by experts. The algorithms and codes developed and verified on the BN-600 test model can be used for both the BN-1200 and BREST reactors and reactors of other types. [ABSTRACT FROM AUTHOR]