POSTIRRADIATION EXAMINATION OF THE PM-3A TYPE 1 SERIAL 2 CORE. PART 1. POSTIRRADIATION EXAMINATION OF FUEL TUBES
BATTELLE MEMORIAL INST COLUMBUS OH COLUMBUS LABS
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The PM-3A Type 1 Serial 2 core was removed from the reactor because of increasing fission product levels in the primary coolant. This increase in level was believed associated with defects in the 347 stainless steel fuel cladding. This examination was to locate defects and determine their cause. Cracks were found to penetrate the outer clad of the tubular elements in high- performance regions. All cracks were longitudinal and intergranular, generally starting at the outer tube surface and terminating at a fuel particle. No evidence of grain boundary precipitates or fuel matrix cracking was observed. On the basis of crack morphology and the similarity of the cracks to cracks attributed to stress-activated corrosion by other investigators, it was concluded that the most probable cause of clad cracking was a stress accelerated chemical attack of unknown origin.
- Nuclear Fission Reactors (Power)
- Fission Reactor Materials