Proposal to Extend CSEWG Neutron and Photon Multigroup Structures for Wider Applications

摘要

The 239-group neutron multigroup structure recommended by the Codes/and Formats Subcommittee of the Cross Section Evaluation Working Group (CSEWG) for use in LMFBR design is not well suited for application in certain other areas, particularly thermal reactor design. This report describes a propos¬al for a neutron group structure consisting of 347 groups, which is an ex-tension of the CSEWG group structure into the thermal range, and also includes more detail in other energy ranges important in LWR, HTGR, GCFR, and CTR design. Similarly, a proposed extension of the CSEWG 94-group photon multigroup structure to 103 groups is described. A subset of the neutron multigroup structure, consisting of 154 groups and for use in power reactor studies, is also presented.