Reactivity Worth Measurement of Calcium Hydride Sample in UTR-KINKI Reactor

Small modular reactors (SMR) using calcium hydride (CaH2) as a moderator have attracted attention due to their passive safety and economic efficiency. In order to design the nuclear design of the SMR, the integral validation of the cross section considering the thermal neutron scattering law(S(alpha,beta)) of CaH2 is necessary. However, there are no integral experiments using CaH2 in the reactor. As the first integral experiment in nuclear reactors, we performed reactivity worth measurements of CaH2 samples in a university training and research reactor (UTR-KINKI) of Kindai University. The measured sample reactivity worth was compared with the results calculated by the continuous energy Monte Carlo code MVP3 and JEFF -3.1, and integral validation of the CaH2 cross section stored in JEFF-3.1 was performed. To obtain the sample reactivity worth components, we carried out perturbation calculations.