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Title: Irradiation response of delta ferrite in as-cast and thermally aged cast stainless steel

To enable the life extension of Light Water Reactors (LWRs) beyond 60 years, it is critical to gain adequate knowledge for making conclusive predictions to assure the integrity of duplex stainless steel reactor components, e.g. primary pressure boundary and reactor vessel internal. Microstructural changes in the ferrite of thermally aged, neutron irradiated only, and neutron irradiated after being thermally aged cast austenitic stainless steels (CASS) were investigated using atom probe tomography. The thermal aging was performed at 400 °C for 10,000 h and the irradiation was conducted in the Halden reactor at ~315 °C to 0.08 dpa (5.6 × 10 19 n/cm 2 E > 1 MeV). Low dose neutron irradiation at a dose rate of 5 × 10 -9 dpa/s was found to induce spinod,al decomposition in the ferrite of as-cast microstructure, and further to enhance the spinodal decomposition in the thermally aged cast alloys. Regarding the G-phase precipitates, the neutron irradiation dramatically increases the precipitate size, and alters the composition of the precipitates with increased, Mn, Ni, Si and Mo and reduced Fe and Cr contents. Lastly, The results have shown that low dose neutron irradiation can further accelerate the degradation of ferrite in a duplex stainless steelmore » at the LWR relevant condition.« less
 [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [1]
  1. Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering
  2. Argonne National Lab. (ANL), Lemont, IL (United States). Nuclear Engineering Div.
  3. Belgian Nuclear Research Center (SCK-CEN), Mol (Belgium)
  4. Boise State Univ., ID (United States). Dept of Materials Science and Engineering; Center for Advanced Studies, Idaho Falls, ID (United States)
  5. Univ. of Wisconsin, Madison, WI (United States). Engineering Physics Dept.; Idaho National Lab. (INL), Idaho Falls, ID (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Nuclear Materials
Additional Journal Information:
Journal Volume: 466; Journal Issue: C; Journal ID: ISSN 0022-3115
Research Org:
Idaho National Lab. (INL), Idaho Falls, ID (United States)
Sponsoring Org:
USDOE Office of Nuclear Energy (NE)
Country of Publication:
United States
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; thermal aging; duplex stainless steel; neutron irradiation; atom probe tomography; delta ferrite
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1252253