Structural characterization of nanoscale intermetallic precipitates in highly neutron irradiated reactor pressure vessel steels
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Univ. of California, Santa Barbara, CA (United States)
Massive, thick-walled pressure vessels are permanent nuclear reactor structures that are exposed to a damaging flux of neutrons from the adjacent core. The neutrons cause embrittlement of the vessel steel that grows with dose (fluence), as manifested by an increasing ductile-to-brittle fracture transition temperature. Extending reactor life requires demonstrating that large safety margins against brittle fracture are maintained at the higher neutron fluence associated with beyond 60 years of service. Here synchrotron-based x-ray diffraction and small angle x-ray scattering measurements are used to characterize highly embrittling nm-scale Mn–Ni–Si precipitates that develop in the irradiated steels at high fluence. These precipitates lead to severe embrittlement that is not accounted for in current regulatory models. As a result, application of the complementary techniques has, for the very first time, successfully identified the crystal structures of the nanoprecipitates, while also yielding self-consistent compositions, volume fractions and size distributions.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); BNL Program Development
- Grant/Contract Number:
- SC00112704; AC02-98CH10886; SC0012704
- OSTI ID:
- 1237167
- Alternate ID(s):
- OSTI ID: 1341516; OSTI ID: 1359850
- Report Number(s):
- BNL-108275-2015-JA; BNL-111938-2016-JA; R&D Project: LS001
- Journal Information:
- Scripta Materialia, Vol. 113, Issue C; ISSN 1359-6462
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
On the Elevated Temperature Thermal Stability of Nanoscale Mn-Ni-Si Precipitates Formed at Lower Temperature in Highly Irradiated Reactor Pressure Vessel Steels
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journal | July 2019 |
Magnetic small-angle neutron scattering
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journal | March 2019 |
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