evelopment of three dimensional discrete ordinates-Monte Carlo coupled system

he radiation shielding calculations of large nuclear facilities are complicated due to their bulk shields and complex geometries. A program system based on three-dimensional discrete ordinates (SN)-Monte Carlo (MC) coupled method has been developed to solve this kind of shielding problems. SN method is used to treat the deep penetration problem in the bulk shield, and MC simulation is performed with complex geometry. The coupled method is implemented in the interface program to calculate the probability of particle variables from the SN angular flux distribution. A special source routine is written and linked to MC code to processed these probability arrays and sample the particle variables to generate source for the use of MC code. The H. B. Robinson Unit 2 pressure vessel benchmark was used to validate the SN-MC coupled program system. The specific activities for the six dosimeters in the surveillance capsule were calculated. Satisfactory agreements were obtained from the comparisons of SN-MC results with those obtained from measurement and other computer codes. The result demonstrates that the SN-MC coupling scheme with the program system is suitable to treat three dimensional shielding problems with satisfactory accuracy.