The production of sup 49 V, sup 93 Mo, sup 93m Nb and other long-lived isotopes in fusion materials with 14 MeV neutrons

Abstract

Results are presented for measurements of neutron cross sections for the production of {sup 49}V (331 d) from vanadium and for {sup 93}Mo (3500 a) and {sup 93m}Nb (16 a) from natural and {sup 94}Mo-enriched molybdenum targets near 14 MeV. The targets were irradiated at the Rotating Target Neutron Source II to fluences up to 10{sup 18} n/cm{sup 2}. Radiochemical separations were performed to separate the desired nuclides from interferring activities. Activity measurements were then performed using x-ray counting techniques. Results are compared with calculations and the measured cross sections are used to predict the level of these activities in a first-wall fusion reactor material. Previous results are also reviewed for similar measurements of the production of {sup 55}Fe, {sup 63}Ni, {sup 59}Ni, {sup 94}Nb, and {sup 91}Nb. Comparisons with theoretical calculations suggest possible revisions of the halflives of {sup 59}Ni and {sup 91}Nb