Spatial-time-dependence of thermal feedback reactivity during control-rod withdrawal test using the HTTR

The control-rod withdrawal test using the High Temperature Engineering Test Reactor (HTTR) was performed as the reactivity insertion test in the safety demonstration test. In order to take the spatial dependence of the temperature coefficient during the transient into the thermal feedback of the dynamic analysis code, we produced the spatial temperature coefficient of the HTTR and adopted it to the analysis of the control-rod withdrawal test. As the result, the reactor power transient using the spatial temperature coefficient agreed well with the experimental result by restraining the power transient overestimating at the preliminary analysis using the power temperature coefficient. (author)