Dynamic analysis of space–time effects in the ISU RACE configuration

We present reactor physics analyses for the accelerator-driven thermal reactor configuration of the Reactor-Accelerator Coupling Experiments Project (RACE) at Idaho State University. A full-core model is developed using the ERANOS deterministic code coupled with the JEF2.2 nuclear data library. A pulsed source experiment is simulated to test performance of the traditional point kinetics and space–time α-methods for reactivity determination. Analysis of the simulated 235U detector responses to a neutron source pulse indicates the inability of point kinetics theory to correctly determine the reactivity for the subcritical RACE configuration. The ERANOS simulation indicates that the traditional α-method overestimates keff by 4.5%, whereas the space–time α-method could yield significant improvements if sufficiently accurate simulations are available.