Two-dimensional cross-section sensitivity and uncertainty analysis for tritium production rate in fusion-oriented integral experiments

Several integral experiments on tritium breeding were jointly performed in connection with the U.S./JAERI Collaborative Program on Fusion Breeder Neutronics. Tritium production rates from /sup 6/Li (T/sub 6/) and /sup 7/Li(T/sub 7/) were measured at several locations in an Li/sub 2/O assembly embedded in the concrete wall of a 5- x 5- x 4.5-m room (reference experiment) in independent benchmark experiments with the Li/sub 2/O assembly located in a large room of negligible room-return neutrons. In the reference experiment, large discrepancies in T/sub 6/ were found at the front locations in the Li/sub 2/O assembly. At middle locations, the calculated-to-experimental (C/E) values for T/sub 6/ are -- 1.2 (U.S.) and -- l.1 (JAERI). The C/E values for T/sub 7/ are -- 1.18 (U.S.) and 1.05 (JAERI). To assess the contribution to the uncertainty is predicting T/sub 6/ and T/sub 7/ that results from the current uncertainties in the nuclear data base, an extensive two-dimensional cross-section sensitivity/uncertainty analysis was performed. For that purpose, the FORSS module, and the VIP and DOT 4.3 codes were used along with the PUFF-2 covariance code. Two systems were considered for the analysis: the benchmark system and the reference system. The models used simulate the geometrical details and source conditions for the experiments