Application of a Nuclear Graphite Irradiated Material Property Normalization Approach

Nuclear grade graphite has several physical characteristics that are advantageous for its use in high-temperature reactors, including a high scatter cross-section and a low absorption cross-section (high moderating ratio). In addition to the neutronics benefits of graphite as a moderator, nuclear grade graphite has high thermal conductivity combined with adequate structural strength at high temperatures. However, the material properties associated with graphite grades that are candidates for high temperature environments exhibit a strong dependence on fast neutron fluence (E >0.1 MeV). The material properties of interest are typically available only at discrete temperature and fluence levels, which may limit the application of graphite materials in high-temperature reactor designs. A technique to interpolate available irradiated material property data within the bounds of the parameters examined in applicable testing programs has been proposed in PVP2024-123523 [4] and applied to the fine-grained Toyo Tanso IG-110 graphite grade irradiation test data. The purpose of this paper is to apply the proposed methodology presented in PVP2024-123523 [4] to an additional fine-grained graphite grade Tokai Carbon G347 to illustrate the broader applicability of the approach. This paper also underscores response similarities between the two graphite grades highlighted by the application of the approach.