Greenwood, Lawrence R.
Physicist, Argonne National Laboratory, Argonne, IL
Pages: 9 Published: Jan 1990
The SPECOMP computer code has been developed to calculate neutron-induced displacement damage cross sections for compound materials such as alloys, insulators, and ceramic tritium breeders for fusion reactors. These new calculations rely on recoil atom energy distributions previously computed with the DISCS computer code, the results of which are stored in our SPECTER computer code master libraries. All reaction channels were considered in the DISCS calculations and the neutron cross sections were taken from ENDF/B-V. Compound damage calculations with SPECOMP thus do not need to perform any recoil atom calculations and consequently need no access to ENDF or other neutron data bases. The calculations proceed by determining secondary displacements for each combination of recoil atom and matrix atom using the Lindhard partition of the recoil energy to establish the damage energy. A separate average displacement threshold energy is assigned to each atom in the compound. Calculations have been completed for stainless steel, vanadium alloys, 6Li-compound tritium breeders, alumina, silicon dioxide (SiO2), (Cu3Au), tantalum oxide (TaO), and (NbTi) superconductors. Cross sections are now being developed for other compounds, however, some research is needed to determine the proper threshold energies for many compounds. All of these energy-dependent cross sections have been added to the SPECTER computer code, thus permitting routine spectral averaging of each dpa cross section for any specified neutron spectrum up to 20 MeV. Calculations can be readily performed for any combination of the 38 elements in SPECTER. The new compound dpa cross sections are compared to atom-weighted results using elemental dpa values. Large differences are noted in cases where there are substantial mass and damage threshold energy differences between the elements. However, the compound dpa effects are quite small for structural materials such as stainless steel.
radiation damage—compounds, lithium oxide (Li, 2, O), SiO, 2, aluminum oxide (Al, 2, O, 3, ), TaO, stainless steel, displacement damage (dpa)
Paper ID: STP49480S