Ponzoni L.M.E.,CNEA Centro Atomico Constituyentes |
Mieza J.I.,CNEA Centro Atomico Constituyentes |
Mieza J.I.,Instituto Sabato |
De Las Heras E.,CNEA Centro Atomico Constituyentes |
And 2 more authors.
Journal of Nuclear Materials | Year: 2013
Delayed hydride cracking (DHC) is an important failure mechanism that may occur in Zr alloys during service in water-cooled reactors. Two conditions must be attained to initiate DHC from a crack: the stress intensity factor must be higher than a threshold value called KIH and, hydrogen concentration must exceed a critical value. Currently the pressure tubes for CANDU reactor are fabricated from Zr-2.5Nb. In this paper the critical hydrogen concentration for DHC and the crack velocity of a developmental pressure tube, Excel, was evaluated and compared with that of Zr-2.5Nb. The DHC velocity values measured in Excel were higher than usually reported in Zr-2.5Nb. Due to the higher hydrogen solubility limits in Excel, its critical hydrogen concentration for DHC initiation is 10-50 wppm over that of Zr-2.5Nb in the range of 150-300 °C. © 2012 Elsevier B.V. All rights reserved.