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Title: Weld repair of helium degraded reactor vessel material

Conference ·
OSTI ID:10135312
; ; ; ;  [1]; ; ; ;  [2]
  1. Westinghouse Savannah River Co., Aiken, SC (United States)
  2. Westinghouse Electric Corp., Pittsburgh, PA (United States). Science and Technology Center

Welding methods for modification or repair of irradiated nuclear reactor vessels are being evaluated at the Savannah River Site. A low-penetration weld overlay technique has been developed to minimize the adverse effects of irradiation induced helium on the weldability of metals and alloys. This technique was successfully applied to Type 304 stainless steel test plates that contained 3 to 220 appm helium from tritium decay. Conventional welding practices caused significant cracking and degradation in the test plates. Optical microscopy of weld surfaces and cross sections showed that large surface toe cracks formed around conventional welds in the test plates but did not form around overlay welds. Scattered incipient underbead cracks (grain boundary separations) were associated with both conventional and overlay test welds. Tensile and bend tests were used to assess the effect of base metal helium content on the mechanical integrity of the low-penetration overlay welds. The axis of tensile specimens was perpendicular to the weld-base metal interface. Tensile specimens were machined after studs were resistance welded to overlay surfaces.

Research Organization:
Westinghouse Savannah River Co., Aiken, SC (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
AC09-89SR18035
OSTI ID:
10135312
Report Number(s):
WSRC-MS-90-298; CONF-910808-9; ON: DE92011174
Resource Relation:
Conference: 5. international symposium on environmental degradation of materials in nuclear power systems - water reactors,Monterey, CA (United States),25-29 Aug 1991; Other Information: PBD: [1990]
Country of Publication:
United States
Language:
English