An assessment of carbon steel containers for radioactive waste disposal

The report describes a study of the corrosion of High Level Nuclear Waste containers in geological disposal. This has concentrated on the use of carbon steel in granitic environments, and has aimed at estimating the corrosion allowance required to achieve a 1000-year life. Experimental and mathematical modelling studies have indicated that 216 mm of steel should be more than sufficient to prevent penetration by general or localized corrosion. There are sound mechanistic reasons to regard this value as an overestimate. The possibility of stress corrosion cannot be dismissed, but, because the process requires a certain minimum stress level before it can occur, it should be possible to avoid the problem by giving the containers a stress relief heat treatment. A conservative assessment has shown that microbial corrosion may cause a maximum additional metal loss of 13 mm. (author)