SEDL / STP / STP1194-EB / STP24880S

The Development of an Experimental Data Base for the Lifetime Predictions of Titanium Nuclear Waste Containers

Ikeda, BM
AECL Research, Whiteshell Laboratories, Pinawa, Manitoba

Bailey, MG
AECL Research, Whiteshell Laboratories, Pinawa, Manitoba

Quinn, MJ
AECL Research, Whiteshell Laboratories, Pinawa, Manitoba

Shoesmith, DW
AECL Research, Whiteshell Laboratories, Pinawa, Manitoba

Pages: 17    Published: Jan 1994

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Abstract

To predict the expected lifetimes of nuclear waste containers under Canadian disposal vault conditions, specific criteria upon which a predictive model can be based must be developed. The anticipated evolution of the corrosion of titanium waste containers is described. Failure is most likely to occur by a combination of crevice corrosion, hydrogen-induced cracking and general corrosion and, for long lifetimes, the duration of crevice corrosion must be limited. The crevice corrosion of Grade-2 and Grade-12 titanium has been studied using a galvanic coupling technique. The propagation of crevice corrosion on the Grade-2 material is dependent on both temperature and oxygen concentration and repassivation occurs once the oxygen is consumed. The propagation of crevice corrosion on the Grade-12 alloy appears almost independent of temperature, and repassivation occurs for T ⩽73°C even in the presence of copious amounts of oxygen. The implications for predicting the lifetimes of containers under disposal conditions are discussed.