Naval Research Laboratory, Washington, D.C.
Nuclear Energy Systems, Westinghouse Electric Corp., Pittsburgh, Pa.
Pages: 13 Published: Jan 1972
A cooperative program between the Naval Research Laboratory and the Westinghouse Nuclear Energy Systems Division was established to explore possible relationships between postirradiation Charpy-V and fracture mechanics (KIc) data. Initial efforts centered on a 6 ⅜-in. AS33 grade B Class 2 steel plate for which the preirradiation condition had been well characterized by Charpy-V (Cv), tension, dynamic tear, and fracture mechanics tests. Low (<250 F, 121 C) temperature-high fluence exposure conditions were utilized to obtain large Cv, tensile and plane strain fracture toughness (KIc) property changes over the preirradiation condition.
The simultaneous exposure of Cv and 1-in.-thick compact tension (CT) specimens produced comparable increases in Cv 30 ft ∙ lb transition temperature and KIc 65,000 psi √in. temperature. The Cv shelf energy was reduced from 74 to 46 ft ∙ lb. The postirradiation 75 F (24 C) yield strength was 127.3 ksi compared to a preirradiation value of 74.2 ksi; however, postirradiation yield strength decreased markedly with increasing temperature.
The test capacity of the 1-in. CT specimen was found insufficient for ASTM valid KIc determinations at the Cv shelf level temperature for pre- or postirradiation conditions. The estimate of postirradiation KIc at Cv shelf temperatures would require a CT specimen thickness of at least 5 in. The data suggest that, if power reactor surveillance programs restrict test specimen size to a maximum of 1-in. thickness, and if the measuring capacity of CT specimens is the function of thickness described by ASTM, an empirical or correlation-projection approach would be required to utilize fracture mechanics specimens in such programs.
fracture (materials), fatigue (materials), fracture strength, impact tests, tension tests, fracture tests, irradiation, yield strength, stresses, cracks, pressure vessel steels
Paper ID: STP38824S