Double Differential Neutron Scattering Cross Sections for Ultra High Temperature Materials

摘要

The five highest melting point materials are1Hafnium, Tantalum, Niobium andZirconium (ZrC) Carbides and Graphite(that sublimes). Graphite is the material forVery High Temperature Reactors (VHTR);Ultra High Temperature Reactors (UHTR),like the thermal nuclear propulsion reactorNERVA2 uses a dispersion of ZrC and UCin graphite as the material for the core.Presently there are neither doubledifferential nor elastic scattering dataavailable that describe the thermalizationprocess in ZrC. We have therefore,calculated for the first time coherent elasticand incoherent inelastic cross sections forthe ZrC crystal which has a face centeredcubic (fcc) lattice. The phonon spectrum forthe ZrC lattice was calculated with the codePHONON using Hellman-Feynman forcescomputed with ab-initio methods in Ref. 3.