COMPARISON OF TESTING RESULTS OF CAST AUSTENITIC STAINLESS STEEL ELBOW MATERIALS FORM BEZNAU UNIT 1 WITH VARIOUS PREDICTION CORRELATIONS FOR FRACTURE TOUGHNESS

摘要

Due to the degradation of the Inconel 600 steam generator tubing, the steam generators at the Nordostschweizerische Kraftwerke AG (NOK) Beznau Unit 1 Nuclear Power Plant were replaced in 1993 after approximately 175,000 hours of operation. Along with the steam generators, the connecting hot and crossover leg elbows made out of static casting of CF8M austenitic stainless steel were replaced with forged stainless steel elbows in order to obtain plant specific fracture mechanics data. Tensile, Charpy (V-notched and U-notched) impact, and fracture toughness (2T-CT) specimens were machined from the elbows and tested at room temperature and 316°C. This paper presents the fracture toughness ss ( J_(IC) , and J-R) results for the Beznau Unit 1 crossover leg and hot leg after 175,000 hours at operating temperatures (290°C and 325°C). The fracture toughness values obtained in this program are compared to the fracture toughness values one would obtain using the various published procedures and correlations for assessing thermal embrittlement.