SEDL / STP / STP939-EB / STP28122S

Prevention of Delayed Hydride Cracking in Zirconium Alloys

Cheadle, BA
Atomic Energy of Canada Limited, Research Company, Chalk River Nuclear Laboratories, Metallurgical Engineering Branch, Chalk River, Ontario

Coleman, CE
Atomic Energy of Canada Limited, Research Company, Chalk River Nuclear Laboratories, Metallurgical Engineering Branch, Chalk River, Ontario

Ambler, JFR
Atomic Energy of Canada Limited, Research Company, Chalk River Nuclear Laboratories, Metallurgical Engineering Branch, Chalk River, Ontario

Pages: 17    Published: Jan 1987

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Abstract

Zirconium alloys are susceptible to a mechanism for crack initiation and propagation called delayed hydride cracking. From a review of component failures and experimental results, we have developed the requirements for preventing this cracking. The important parameters for cracking are hydrogen concentration, flaws, and stress; each should be minimized. At the design and construction stages hydrogen pickup has to be controlled, quality assurance needs to be at a high enough level to ensure the absence of flaws, and residual stresses must be eliminated by careful fabrication and heat treatment.