Fracture toughness PWR internals. ECN contribution to CEC contract on PWR internals-part 2, (ETNU/CT/94/0136-F)

This report presents the results of the collection and subsequent analysis of fracture toughness data on the austenitic stainless steels used in PWR internals. These data were made available by CEA Saclay and ECN Petten in the framework of a CEC study contract on PWR internals. The data include austenitic stainless steel plate 304L and 316L, as well as the weld metals 308L, 19-12-2, 17-13-2 and 16-8-M. Test specimens of these materials were irradiated in earlier programs, up to doses of 30 dpa at temperatures of approximately 400 C. Test specimens include several CT-type and impact test specimens. The results show a degradation of the fracture toughness with increasing irradiation dose. The degradation in terms of the ratio of the fracture toughness at 1 mm crack extension of irradiated to unirradiated material, turns out to be remarkably similar for all materials, a common trend curve can be fitted through the data points. In general there is a quick degradation of the fracture toughness during the first 5 dpa's, at higher doses the degradation seems to saturate. (orig.)