Helium Production in Pure Elements, Isotopes, and Alloy Steels by 14.8-MeV Neutrons

The results of an extensive series of total helium production cross-section measurements for incident neutrons in the 14- to 15-MeV energy region are presented, and an experimental data base for the prediction of helium generation in candidate fusion reactor materials is provided. The measurements were made by isotope-dilution gas mass spectrometry. They include the pure elements Be, B, C, O, F, AI, Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Nb, Mo, Ag, Sn, Ta, Pt, Au, and Pb; the separated isotopes of B, Fe, Ni, Cu, and Mo; and the alloy steels Type 316 stainless steel, HT-9, and 9 Cr-1 Mo. The results are in generally good agreement with other total helium production measurements in the literature, but comparisons with the ENDF/B- V nuclear data file indicate that the helium gas production files require revision for the structural elements vanadium, chromium, manganese, cobalt, and nickel. Comparisons with published cross sections for individual reaction channels indicate that reactions other than (n,α) contribute significantly to helium production in several materials.