Preliminary Computational Analysis of Reactivity Effects Due to Heating of the Astra Critical Stand

A computational model of the ASTRA critical stand with heating has been prepared for the purpose of studying the neutron-physical characteristics of modular reactors of the type GT-MGR. The reactivity input during heating and cooling of the stand is evaluated. It is shown that the behavior of the reactivity upon heating and cooling will be different because an electric heater is present at the center of the internal reflector and a layer of thermal insulation is present between the core and the outer reflector. A nonequilibrium contribution of different regions of the assembly in the integral temperature effect is found. It is suggested that this effect can be used in preparation for experiments performed on the critical stand.