NMSS-0003: Corrosion of Sealed Sources Caused by Sensitization of Stainless Steel Source Capsules During Shipment

DESCRIPTION

This issue was identified[1]by NMSS with the discovery of intergranular corrosion in one manufacturer's 316L stainless steel source used in Category IV irradiator pools. Analysis of data and reports provided by the

manufacturer revealed that the 316L stainless steel sources were heat sensitized as a result of improper loading in their shipping containers. The heat generated by the high activity sources resulted in higher than normal temperatures inside the containers. The combination of these higher temperatures and poor quality pool water made the sensitized stainless steel vulnerable to intergranular corrosion.

CONCLUSION

The issue was resolved[2]with the issuance of IN 96-54.[3]

[1] Memorandum for L. Shao from D. Cool, "Submittal of Generic Safety Issues," April 12, 1996. [9605170029]

[2] Memorandum for F. Coffman from J. Piccone, "Status of NMSS Generic Safety Issues," December 15, 1997. [9712180068]

[3] Information Notice 96-54, "Vulnerability of Stainless Steel to Corrosion When Sensitized," U.S. Nuclear Regulatory Commission, October 17, 1996. [ML031050603]