Sample worth measurement with systematically changed mixing ratio of Lead and Bismuth in KUCA

Oizumi, Akito   ; Yamanaka, Masao*; Fukushima, Masahiro   ; Pyeon, C. H.*

Sample reactivity worths of Lead (Pb) and Bismuth (Bi), which are a coolant candidate for the accelerator driven system (ADS), have been independently measured for the integral evaluations of their cross sections in the relatively hard neutron spectrum in the Kyoto University Critical Assembly (KUCA), respectively. There is a difference between C/E values of Pb and Bi which are obtained by comparing experimental analysis values using the Monte Carlo calculation code MCNP with the JENDL-4.0 nuclear data library with the measured values. In this experiment, in order to complement the measured values of simple substances of Pb and/or Bi, the sample reactivity worth measurements with systematically changed mixing ratio of them were carried out under the same conditions as the past experiments in the KUCA. First, the reproducibility of past experiments was confirmed from the measurement result of Pb simple substance (Pb100%). In addition, it was confirmed that the new measured values different in the lead volumetric filling ratio obtained in this experiment supplement between the measured values of simple substances of Pb (Pb100%) and Bi (Pb0%) in the past. In the future, the analyses of these series of experiments and the evaluations of C/E values will be carried out by using nuclear data libraries of JENDL, ENDF, and JEFF. By using the sensitivity analysis, we will identify the nuclides and their reactions responsible for the differences between the experimental and measured values and among the each nuclear data library.