Burst Test Qualification Analysis of DWPF Canister-Plug Weld

Abstract

High level radioactive waste canisters are sealed by resistance upset welding to ensure leak tight closures. Resistance welding is fast, uniform, and can be performed remotely to minimize radiation exposure to the operators. Canisters are constructed in accordance with ASME Band PV Code, Section VIII, Division 1, however, the resistance welds are not used in Section VIII. The resistance welds are qualified by analysis using material properties obtained from the test coupons. Burst tests are performed on canister welds to meet ASME Section IX welder qualification requirements. Since burst tests are not used in Section IX for resistance weld qualification, finite element results of canister resistance welds are compared with the finite element analysis results of resistance weld tests in ASME Section IX, QW-196 to establish similarity between the two weld tests. Detailed analyses show that the primary mode of failure in both the tests is shear and, therefore, the use of burst test in place of shear test is acceptable. It is believed that the detailed analyses and results could help in establishing acceptance criteria for resistance upset welding in ASME B&PV Code, Sections VIII, and IX.