Implications of neutron spectrum and flux differences on fission-fusion correlations at high neutron fluence

Abstract

The application to fusion environments of materials data derived from fission reactors involves considerations related not only to neutron spectra but also the often dominant effect of displacement rate. It is shown in this paper that fission-fusion correlation experiments directed toward helium effects and PKA recoil spectra are frequently difficult to interpret due to the strong influences of displacement rate, low energy recoils from thermal neutron absorption and in some cases a large influence of solid transmutants. It is also shown that materials data published in earlier decades must be reevaluated in light of recent advances in defining irradiation parameters.

Phase-field modeling of void evolution and swelling in materials under irradiation

“…For instance, 88% swelling in stainless steel AISI 316 was reported during neutron irradiation at 510°C in Experimental Breeder Reactor-II (EBR-II) [1]. The largest reported swelling of AISI 316 was 260%, as irradiated by 140 keV protons at 625°C [2].…”

Effect of initial oxygen content on the void swelling behavior of fast neutron irradiated copper

“…The calculated minimum concentration of helium needed to stabilize the cavities nucleated in neutron-irradiated copper is a strong function of temperature, ranging from $0.1 appm He at 200°C to $0.001 appm He at 400°C [4]. Using the fast reactor helium generation rate in copper of $0.1 appm/ dpa [16,17], energetically stabilized cavity nuclei would be predicted to occur at doses above $0.01 dpa for neutron irradiation near 400°C. Since the cavity population in the low-oxygen copper specimen would be stabilized by helium during the early stages of the neutron irradiation, no difference in the cavity density or size of low-oxygen versus oxygen-doped copper would be expected on the basis of the energy-minimization model [4].…”

Cross-sectional TEM and X-ray examination of radiation-induced stress relaxation of peened stainless steel surfaces

“…Whereas it was earlier thought that, compared to neutrons, displacements induced by protons, electrons or gamma rays would be more effective in surviving recombination [13][14][15][16] and thereby cause more damage. More recent studies have shown that there appears to be no difference in displacement effectiveness, at least for relatively low temperatures experienced in BWR shrouds and pressure vessel walls [17][18][19][20][21].…”