Residual Stess Testing of Outer 3013 Containers

The Department of Energy (DOE) Complex is packaging plutonium (Pu) containing materials for eventual storage at various sites in the complex. The Pu materials are packaged according to the DOE 3013 standard which outlines general requirements relevant to the planned DOE activities to stabilize Pu materials, package them in 3013 containers, and place them in long-term storage until future facilities are available to convert these materials to other forms. Container sections of the 3013, in both the as-fabricated condition as well as the closure welded condition, were evaluated per ASTM standard G-36-94, an aggressive testing procedure using boiling MgCl₂ solution to reveal the relative stress corrosion cracking susceptibility of a material. Significant cracking was observed in the bottom half of the as-fabricated can near the base-to-can fabrication weld. This observation indicates that sufficient residual stresses exist to provide the stress component necessary for stress corrosion cracking in the as fabricated 3013 container. Additionally, cracks were observed in both the lid and the body of gas tungsten arc welded and laser beam closure welded containers as a result of this test technique. The presence of cracks in both of the closure welded container samples tested indicates that significant residual stresses are inherent in the closure welding process regardless of the closure weld method.