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Title: Correlation of mechanical property changes in neutron irradiated pressure vessel steels on the basis of spectral effects

Technical Report ·
DOI:https://doi.org/10.2172/6168423· OSTI ID:6168423

Defect production functions derived from atomistic modeling were evaluated for use in correlating yield stress changes of A212B and A302B pressure vessel steels irradiated in a wide variety of neutron spectra at low temperatures (40--90{degree}C) and low doses (<0.1 dpa). The irradiations were performed in RTNS-II, OWR, ORR and the HFIR pressure vessel surveillance positions. The data from RTNS-II, OWR and ORR are correlated fairly well on the basis of dpa, but the data from HFIR show that only one tenth as many dpa are needed to produce the same radiation-induced yield stress changes as in the other neutron spectra. About 96% of the neutrons in the HFIR surveillance position are thermal neutrons, and a significant fraction of the displacements is produced by recoils from thermal neutron captures. The best correlation of all the data is achieved when the property changes are compared on the basis of the production of freely migrating self-interstitial defects, which better represents the defects participating in the radiation strengthening process.

Research Organization:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Organization:
DOE/ER
DOE Contract Number:
AC06-76RL01830
OSTI ID:
6168423
Report Number(s):
PNL-SA-17094; ON: DE91005044
Country of Publication:
United States
Language:
English