Estimating the Reactivity of the Yalina-Booster Fast-Thermal Subcritical Assembly without Fuel in the Fast Zone

Abstract

The geometry and material content of the Yalina-Booster two-zone subcritical assembly driven by external neutron sources are described, along with the instrumentation and conditions of experimental measurements. ²⁵²Cf isotope and a neutron generator with a TiT or TiD neutron-producing target are used as external neutron sources. The results are presented from analytical and experimental estimates of the levels of subcriticality in two core configurations: (1) with a fueled core (uranium dioxide of 10% enrichment in the thermal zone and uranium dioxide of 21% enrichment in the fast zone) and (2) with uranium dioxide of 10% enrichment in the thermal zone and without fuel in the fast zone. The calculated effective fractions of delayed neutrons in the considered thermal zone are compared. It is shown that the main kinetic parameters are defined by the thermal zone. The calculated results are compared to experimental ones, and the discrepancies are analyzed.