Measurement of tritium production rate in water cooled pebble bed multi-layered blanket mockup by DT neutron irradiation experiment

Abstract

For the first time, tritium production rates in the water cooled pebble bed blanket are experimentally examined by using DT neutrons with two partial mockups; multi-layered mockup with water and pebble bed mockup. Tritium production rates (TPRs) are calculated by numerical analyses using Monte Carlo code MCNP-4C with nuclear data libraries FENDL-2.1 and JENDL-3.3. For experimental analysis on the pebble bed mockup, precise modelling method is proposed using the hexagonal close-packed heterogeneous geometry. Prediction uncertainties of TPRs are clarified through the experimental analyses. Ratios of the calculation results to the experimental results on local TPRs are 0.89–1.10 in the multi-layered mockup, and 0.95–1.13 in the pebble bed mockup. The calculation results on integrated tritium productions agree well with the experimental ones in both mockups. It is clarified that integrated tritium productions can be accurately evaluated.