Neutron environmental characterization requirements for reactor fuels and materials development and surveillance programs

Neutron environmental characterization requirements for reactor fuels and materials development and surveillance programs for Light Water Reactors (LWRs), High Temperature Gas-Cooled Reactors (HTGRs), Fast Breeder Reactors (FBRs), and Controlled Thermonuclear Reactors (CTRs) are varied. Presently, the most demanding requirements are associated with the development of FBRs where goal accuracies in the range of 1 to 3% have been requested for the determination of fission rates, burnups, and neutron fluxes and fluences. Total fluence associated with a measured material property change in a fast test reactor can presently be determined in the 5 to 10% range, and application of improved dosimetry techniques is expected to reduce this to the 2 to 5% range. Without direct dosimetry measurements, however, uncertainties of 25% and more are not uncommon. International standardization, development, and application of improved dosimetry methods for reactor materials development and surveillance programs for LWRs, HTGRs, FBRs and CTRs are essential. The discussion of requirements for neutron environmental characterization for these different reactor concepts is an important aspect of this conference. Here, these requirements are reviewed in light of currently known design, development, testing, and operation considerations for U.S. LMFBR and CTR programs