A discrete ordinates transport code ENSEMBLE in (X, Y, Z) geometry has been developed for the purpose of shielding calculations in three-dimensional geometry. The code has some superior features, compared with THREETRAN which is the only code of the same kind so far developed. That is, the code can treat higher order anisotropic scattering and employs a coarse mesh rebalancing method. Moreover it has a negative flux fix-up routine using a variable weight diamond difference equation scheme and has a ray-effect fix-up option using a fictitious source based on Sw .. PN-1 conversion technique. Formulations for these advanced features in three-dimensional space have been derived.As the demonstration of the capabilities of the code, several numerical analyses and an analysis of an annular duct streaming experiment in JRR-4 at Japan Atomic Energy Research Institute, have been performed.As a result of these analyses, confirmation has been obtained for the prospect of applicability of ENSEMBLE to practical shielding design.

The JASPER Experiment had been conducted to obtain useful information on FBR shielding analysis accuracy. Results obtained from the post-experimental analyses are summarized in this paper. Both characteristics for bulk shielding attenuation and streaming of neutron through configurations consisting of several materials including B 4C, stainless steel, sodium and etc. were clarified and the analysis accuracy confirmed. The shielding analysis system for fast reactors has been improved and verified. These experimental data and analytical results were reviewed from a viewpoint of the applicability to the shielding design analysis of the DFBR. Useful information to be utilized in the design study of the DFBR is accumulated through those activities.

No abstract

No abstract

No abstract