SHIELDING BENCHMARK EXPERIMENT FOR SPENT FUEL DRY STORAGE FACILITY

摘要

The large-scale interim spent fuel dry storage facilities from nuclear power plants are plannedrnto start operation by 2010 in Japan. The requirements of these facilities are a big spent fuelrnstorage capacity and a restricted site usage close to the boundary. These cause a strong requestrnof precise and realistic dose estimation for licensing procedure. To resolve this difficulty threerndimensional Monte Carlo calculation methods are introduced, which is always requested torncompare the benchmark experiment of the shielding system for the verification of procedurernand statistical errors. Here, two kinds of shielding benchmark experiments; the huge ductrnstreaming and the cask shadow shielding experiments, were newly prepared to get thesernabsent data.rnAs a first step, the huge duct streaming experiment is outlined and the obtained results arerndiscussed. Neutron and gamma flux and dose distributions in and around the streaming ductrnwere measured by moderating type neutron detectors, neutron dosimeters, activation foils,rnsolid state track detectors (CR-39), thermoluminescent dosimeters, glass dosimeters, etc.rnThese results are also compared with the Monte Carlo calculations. Through these proceduresrnthe know-how of the spatial dose estimation in and around a huge streaming duct werernobtained.