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U.S. Department of Energy
Office of Scientific and Technical Information

Radiation embrittlement and annealing of VVER pressure vessels

Conference ·
OSTI ID:5618805
 [1]
  1. Brookhaven National Lab., Upton, NY (USA)
Pressure vessels of the Soviet-designed VVERs are exposed to up to 10X the fast flux of the vessels of US PWRs. They are fabricated of 2 1/2% Cr, 1% Mo or 2 1/2% Cr, 1% Ni steels developed for that purpose. Consequently, the data base on irradiation effects differs somewhat from that of Western-designed pressure vessels. The role of phosphorus, which is high in the older VVER steels, is especially important. Newer grades of steels, low in copper and phosphorus, have been developed. Pressure vessels fabricated before about 1980 were unclad. The embrittlement of these can be tested in situ with a remote microhardness measuring device. Hydrogen pickup from corrosion does not increase the embrittlement due to irradiation. Considerable research has been performed on pressure vessel annealing, and anneals of the core weld region of the pressure vessels of three operating VVERs have been completed at temperatures 160-185{degree}C higher than the irradiation temperature for 150 hours to one week. Recoveries, monitored with a remote microhardness tester, have ranged upward from 70%.
Research Organization:
Brookhaven National Lab., Upton, NY (USA)
Sponsoring Organization:
DOE/NE
DOE Contract Number:
AC02-76CH00016
OSTI ID:
5618805
Report Number(s):
BNL-43164; CONF-890820--4; ON: DE90000031
Country of Publication:
United States
Language:
English