Development of integrated shielding analysis code system RADHEAT-V4

A modular code system RADHEAT-V4 has been developed for performing precisely neutron and photon transport analyses, and shielding safety evaluations. The system consists of the functional modules for producing coupled multi-group neutron and photon cross section sets, analyzing the neutron and photon transport, and calculating the atomic displacement and the energy deposition due to these radiations in a nuclear reactor or shield. A new method for evaluating accurately angular distributions of radiation fluxes has been developed and introduced into the code system. A multigroup cross section library named JSD1000 has been prepared for shielding design and safety calculations in a new form of direct-access data storage. To evaluate the accuracy and applicability of the code system and the library, systematic calculations have been performed for various benchmark problems. The results of three typical benchmark ploblems and some test calculations of strong anisotropic ploblems are presented. From the above results, it is concluded that RADHEAT-V4 is successfully applicable to evaluating shielding problems accurately for fission and fusion reactors and the new method applied to the code system is effective for eliminating negative values and oscillations of angular fluxes in a medium having an anisotropic source or a strong streaming. (author)