Fusion-relevant helium-e?ects experiments conducted on austenitic steels in the Materials Open Test Assembly (MOTA) of the Fast Flux Test Facility (FFTF) fast reactor had to recognize the contributions of both the high neutron energy (n,a) reactions and that of the 58Ni(n, lamda) 59Ni(n, alpha) reaction sequence with low energy neutrons. An experiment conducted in the harder neutron spectra found within the core of Experimental Breeder Reactor-II (EBR-II) has shown that the helium in this reactor was generated almost exclusively from the interaction of high energy neutrons with the natural isotopes of nickel. There was very little contribution from 59Ni. The helium production was found to scale directly with the nickel content over the range 25 +/- 75% Ni. Even at very high neutron exposures, the helium production in such reactors can be predicted within 5% accuracy on the basis of high energy reactions, as demonstrated by an experiment conducted on three Fe+/- 15Cr+/- Ni ternary alloys irradiated to doses of 75+/- 131 dpa in EBR-II.
Revised: March 28, 2003 |
Published: October 1, 1998
Citation
Garner F., B.M. Oliver, and L.R. Greenwood. 1998.The Dependence of Helium Generation Rate on Nickel Content of Fe-Cr-Ni Alloys Irradiated to High dpa Levels in EBR-II.Journal of Nuclear Materials 263, no. Part B:1740-1744.PNNL-SA-31664.