Proton-induced Relaxation of Surface Stresses Resulting from Peening of Welds in Annealed 304 Stainless Steels
The irradiation induced stress relaxation of peened surfaces in 304 stainless steel was simulated using 3.2 MeV protons. The specimens employed were annealed 304 bars that had been shot-peened to produce a compressive layer on the surface. Irradiation proceeded at 288 C to four dose levels in the range 0.1-2.0 dpa, which almost covers the range experienced by a BWR shroud over a 40 year lifetime. One set of specimens was as-peened and a second set were pre-injected with 25 appm He to assess the potential of bubble-induced acceleration of irradiation creep. Another set of specimens were thermally annealed only. Both surface and depth-dependent measurements of the internal stress were conducted using an X-ray stress analyzer. Electron microscopy was then used to study the microstructural evolution as a function of depth. The results indicated that the compressive stress state was progressively relaxed during irradiation. However, the compressive stress was maintained over the 2 dpa lifetime with no indication of a possible reversal of stress state at the surface. Helium addition did not significantly affect the relaxation and no significant bubble formation was observed.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 860061
- Report Number(s):
- PNWD-SA-6042; TRN: US200523%%190
- Resource Relation:
- Conference: 11th International Conference on Environmental Degradation of Materials in Nuclear Power Systems-Water Reactors, 121; American Nuclear Society,La Grange Park,,United States.
- Country of Publication:
- United States
- Language:
- English
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