Neutronics calculations of HTTR with several nuclear data libraries

Goto, Minoru  ; Nojiri, Naoki ; Shimakawa, Satoshi

Benchmark calculations for several HTTR core conditions were performed with four cross-section sets which were generated from JENDL-3.3, JENDL-3.2, ENDF/B-6.8 and JEFF-3.0 using a continuous energy Monte Carlo code MVP. The core conditions were an annular form core at room temperature and a full core with cylindrical form at room temperature and at full power operation. Study of k discrepancies caused by difference of the nuclear data libraries and identification of nuclide which gives large effects on the k discrepancies were carried out. Comparison of the k between calculations and experiments was also carried out. As the results, for each HTTR core conditions, JENDL-3.3 gives the k agreement with the experiments within 1.5%k, JENDL-3.2 gives the k agreement within 1.7%k, and ENDF/B-6.8 and JEFF-3.0 give k agreement within 1.8%k. There is little k discrepancy between ENDF/B-6.8 and JEFF-3.0. The discrepancy between JENDL-3.3 and JENDL-3.2 is caused by difference of U-235 data and has temperature dependency. The k discrepancy between JENDL-3.3 and ENDF/B-6.8 or JEFF-3.0 is caused by difference of graphite data.