Light water reactor pressure vessel surveillance dosimetry improvement program. Volume 1. Notch ductility and fracture toughness degradation of A 302-B and A 533-B reference plates from PSF simulated surveillance and through-wall irradiation capsules

Mechanical properties data have been developed for two of the materials: the ASTM A302-B correlation monitor reference plate and the A533-B plate No. 03 from the NRC's Heavy Section Steel Technology Program. These results are presented together with an overview of specimen irradiation and testing procedures. Data comparisons are used to describe the observed toughness gradient produced by irradiation where fluences were typical of vessel end-of-life conditions. In addition, assessments are made of the relative irradiation effect at surveillance capsule vs. through-wall locations and the correspondence of Charpy-V vs. fracture toughness test methods in their independent descriptions of radiation-induced embrittlement. Irradiation in the simulated surveillance capsule location was found to reproduce reasonably well the irradiation effect to vessel inner surface and quarter wall thickness positions. As expected, the adjustment of the ASME lower bound (i.e., dynamic) K/sub IR/ toughness curve by the radiation induced elevation of the Charpy-V 41 J and the compact specimen 100 MPa √m temperatures was conservative when compared against the static toughness data. However, the temperature elevation of the C/sub v/ curve (41 J level) with irradiation frequently did not provide a conservative estimate of the temperature elevation defined by fracture toughness tests (100 MPa √m level). On the other hand, correction of the fracture toughness data for lack of test specimen constraint (β/sub Ic/-correction) results in transition temperature elevations less than the C/sub v/ 41 J elevations, in most cases. Overall, the toughness gradient observed between in-wall locations after irradiation was small for both materials; the difference between transition temperatures for wall surface vs. mid thickness locations was 310C or less, independent of the test method used. Candidate areas for future research investigation are discussed