Analysis of Porosity Associated with Hanford 3013 Outer Container Welds
One of the current priorities within the Department of Energy (DOE) complex is the stabilization, packaging and storage of plutonium-bearing materials. The packaging is key to the safe long-term handling and storage of these materials. Packaging consists of placing the stabilized materials into a set of two nested stainless steel containers. The filled and sealed inner container (secondary barrier) is placed into an outer container which is designated as the primary barrier against release to the environment. Together, they provide the required double containment. The outer container and closure weld were intended to comply with the rules for design, fabrication and examination of ASME Section VIII code, to the extent feasible. Post closure-weld hydrostatic testing is not practicable, due to the container contents. In an effort to establish an equivalent level of weld quality, sensitive leak testing of each production closure and periodic (1 in 25 production closures) radiographic and metallographic examination of test containers (production outer containers with non-radioactive surrogate materials) was specified. During production operations, volumetric examination of these periodic test welds identified a trend in which porosity (typically a single pore) may form at the weld tie-in (the point where the leading edge of the advancing weld puddle intercepts the weld start). A limited number of these pores failed to meet specified acceptance criteria (exceeded maximum diameter limit). This paper describes an investigation into the cause (and ultimately the prevention) of the intermittent appearance of unacceptable porosity in closure welds of the outer container made by a GTAW process.
- Research Organization:
- Savannah River Site (SRS), Aiken, SC (United States)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC09-96SR18500
- OSTI ID:
- 803395
- Report Number(s):
- WSRC-MS-2002-00738; TRN: US200302%%176
- Journal Information:
- Practical Failure Analysis, Other Information: PBD: 18 Oct 2002
- Country of Publication:
- United States
- Language:
- English
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