Nuclear model calculations of long-lived isomer production in neutron reactions for fusion reactor technology

Intense neutron fluxes within fusion reactors that are currently being designed will lead to the activation of structural components, and to assess and minimize this radioactivity, nuclear cross sections are needed for neutrons with energies up to 20 MeV. We describe research performed for the International Atomic Energy Agency (IAEA) Coordinated Research Programme on activation cross sections for fusion reactor technology, which has selected certain high-priority reactions for both experimental and theoretical study. Using statistical model codes, we have investigated excitation function cross sections for radionuclide production in the reactions {sup 94}Mo(n,p){sup 94}Nb, {sup 109}Ag(n,2n){sup 108m}Ag, {sup 151}Eu(n,2n){sup 150m} Eu, {sup 153}Eu(n,2n){sup 152g+m2}Eu, {sup 159}Tb(n,2n){sup 158}Tb, {sup 187}Re(n,2n){sup 186m}Re, {sup 179}Hf(n,2n){sup 178m2}Hf, {sup 193}Ir(n,2n){sup 192m2}Ir. Using our calculated results for the excitation functions, along with calculations by other groups, the theoretical excitation functions have been normalized to experimental values at 14.5 MeV to produce evaluated excitation functions. These evaluations can be used within radiation transport and nuclide inventory codes to design, and assess the environmental impact of, fusion reactors. 23 refs., 4 figs., 1 tab.