CRITICAL EXPERIMENTS AND ANALYSIS ON THORIUM AND NATURAL URANIUM TEST ASSEMBLIES IN UTR-KINKI FOR NUCLEAR DATA EVALUATIONAtomic Energy Research Institute, Kinki University Kowakae, Higashi-Osaka, Osaka-fu 577, Japan Keiichiro Tsuchihashi Japan Atomic Energy Research Institute Tokai-mura, Naka-gun, Ibaraki-ken 319-11, Japan Integral critical experiments on thorium and natural uranium test assemblies which are installed in the center of internal graphite reflector of UTR-KINKI, Kinki University Reactor, have been performed. The experiments include (1) Measurement of the reactivity effect of the space between thorium metal plates or natural uranium metal plates in the test assembly and (2) Measurement of detailed relative vertical neutron flux distributions in the assembly. Analytic calculation by JAERI Thermal Thermal Reactor Standard Code System for Reactor Design and Analysis (SRAC Code System) was also performed. The calculated results agree fairly well with the measured values when JENDL-3T and ENDF/B-V nuclear data files were used. KEYWORDS: critical experiment, thorium, natural uranium, reactivity effect, JENDL-3T, ENDF/B-V, SRAC |