Nuclear Sources of Hydrogen in CANDU Fuel Channels

Abstract

The contribution to hydrogen ingress from nuclear reactions is evaluated. The sources of hydrogen investigated are: (n,p), (n,d),(n,t), (y,p) and (y,d) in Zr, Nb and impurities in the fuel channel materials; knock-on recoiling protons and deuterons from elastic scattering of neutrons from water; and protons from photodisintegration of deuterium. The total ingress from the nuclear sources over 20 years is calculated to be less than 4 ppm by wt. The study points to impurities like nitrogen that could generate high levels of hydrogen from the 14N(n,p)14C reaction.