Exploratory Test of 288deg C Radiation Resistance of Two USSR-Produced Reactor Pressure Vessel Steels

摘要

The effects of 288deg C (550deg F) irradiation to 1.0 X 10~19 n/cm~2, E > 1 MeV, on the Charpy V-notch ductilities of two USSR-produced forging materials were determined experimentally. The materials were provided by the Kurchatov Institute under the umbrella of a joint USA-USSR agreement and represent the Cr-Mo-V forgings employed in the construction of USSR light-water VVER-440 reactor pressure vessels (RPVs) before and after 1980, respectively. The primary difference between the two materials is phosphorus conten (0.019percent vs. 0.007percent P) consistent with their respective USSR Steel Specifications 15Kh2MFA and 15Kh2MFA-A. Specimens for post-irradiation property determinations were irradiated in the Ford Nuclear Reactor in a controlled-temperature assembly at an average fluence rate of 5.6 X 10~12 n/cm~2 -s, E > 1 MeV. The post-irradiation CharpyV-notch 41 J (30 ft-lb) transition temperature elevation for the material representing pre-1980 RPVs was 31deg C (55deg F). This elevation was accompanied by a 27percent reduction in Charpy V-notch upper-shelf energy level. For the material representing the post-1980 RPVs, the transition temperature elevation was <= 8deg C (15deg F); the concomitant post-irradiation reduction of upper-shelf energy was not established.