Pressure tube elongation rates in CANDU fuel channels.

Abstract

At present, operating reactors provide the most reliable data base on elongation rates for Zirconium-Niobium pressure tubes in CANDU reactors. The reactor data indicate that there are differences in elongation rates across the reactor face and between reactors, especially between those reactors having substantially different operating conditions, that cannot be explained by differences in the operating flux levels. Although it was initially believed that the flux in some way contributed towards this variability in elongation rate in that the rate was not directly proportional to flux, the general conclusion of this paper is that temperature and ultimate tensile strength make the greatest contribution to the variability.