Integral experiments with a cylindrical multiplying system of metal plutonium

Abstract

The paper presents the results of critical, correlation, and spectral precision experiments carried out at the FKBN‑2 assembly machine using a cylindrical multiplying system made of low-background α‑phase plutonium. In the experiments, the critical state of the multiplying system was determined, the characteristics of non-stationary prompt neutron processes were investigated, and the number of nuclear reactions in the detectors was measured at a controlled power level of the multiplying system. After constructing a benchmark model for the multiplying system, a computational simulation of integral experiments was carried out. Based on the experimental results, the average lifetime of prompt neutrons and the effective fraction of delayed neutrons for the multiplying system were determined. The obtained results can be used to verify the codes of neutron-physics and refine neutron constants.