PNNL

Abstract

For nickel-containing alloys irradiated in thermalized neutron flux spectra the formation and reaction of Ni-59 with thermal neutrons can lead to significant time-varying changes in displacement damage rate, gas formation and nuclear heating. In a CANDU reactor Ni-alloys are used as tensioning springs, fuel channel spacers (in the form of garter springs) and as sheathing and co-axial cables in flux detector assemblies. Prediction of the irradiation processes that affect the functionality of these CANDU internals, such as irradiation embrittlement and irradiation creep, especially under conditions of plant life extension, necessitates a consideration of the effect of the transmutation of Ni.