Fast Reactors and Accelerator Driven Systems Knowledge Base

Conference Article: A re-evaluation of helium/dpa and Hydrogen/dpa ratios for fast reactor and thermal reactor data used in fission-fusion correlations

Abstract

The ⁵⁹Ni isotope produced by the ⁵⁸Ni (n,gamma) reaction has three highly exothermic reactions, (n,alpha), (n,p) and (n,gamma). These reactions contribute to the displacement damage and two of them can generate significant amounts of helium and hydrogen. The production of helium in EBR-II at high neutron exposure has been measured and found not to include a significant contribution from ⁵⁹Ni in those core volumes where most material's data were generated. This is in contrast to a significant ⁵⁹Ni contribution that occurs in the softer below-core areas of FFTF. The often overlooked ⁵⁹Ni contribution to hydrogen generation is of particular importance when considering neutron spectra with a substantial thermal neutron component, however. Inclusion of the (n,p) and (n,gamma) recoil events in the dpa damage calculations requires only a 3% correction to the previously published value, indicating the most of the damage arises from the (n,alpha) reaction

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Reference:

Influence of high dose irradiation on core structural and fuel materials in advanced reactors. Technical committee meeting, Obninsk (Russian Federation), 16-19 Jun 1997

International Atomic Energy Agency, Vienna (Austria)

IAEA-TECDOC--1039, pp:239-249