A302 B steel cladded with stainless steel is used as the pressure vessel material for the two 210 MW(e) boiling water reactors commissioned during 1968. Fabricated surveillance specimens, representative of the pressure vessel steel, were kept in the reactor at wall, shroud, core, and steam dryer locations of the reactor. Charpy V-notch impact and tension specimens from base, weld, and heat affected zone (HAZ) from these locations, except at the core, were tested in the hot cell.
It has been found that maximum shift corresponding to Charpy 41-J index temperature was observed for the base material at the shroud location and the estimated value was 38°C. The corresponding index temperature was 18°C. The irradiation capsules had iron, copper, and nickel flux monitors. These were analyzed for estimating the fluences (> 1 MeV), which were found to be (2.2 ± 0.4) × 1018 n/cm2 for wall and (1.5 ± 0.3) × 1019 n/cm2 for the shroud locations.
The shift in index temperatures was compared with the trend curves of Regulatory Guide 1.99.1.