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U.S. Department of Energy
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IPTS (Integrated Pressurized-Thermal-Shock) study for H. B. Robinson (HBR-HYPO)

Conference ·
OSTI ID:6584413

A primary purpose of the US Nuclear Regulatory Commission (NRC) Integrated Pressurized-Thermal-Shock (IPTS) Program, completed in 1985, was to develop an integrated probabilistic approach for evaluating pressurized water reactor (PWR) pressure vessel integrity; and the scope included the application of the methodology to three high risk'' PWR plants. The three plants selected were Oconee Unit 1, Calvert Cliffs Unit 1, and HBRobinson Unit 2 (HBR-2); and the plant studies were conducted in that order. As a result of this sequence and the developmental nature of the program, the HBR-2 study was the more complete and state-of-the-art. However, by the time the HBR-2 study was conducted, a reevaluation of vessel chemistry and reference nil-ductility transition temperature (RT{sub NDT}) had indicated relatively low concentrations of copper and nickel and low values of initial RT{sub NDT}(RT{sub NDT{sub 0}}), resulting in very low probabilities of failure. Thus, for illustrative purposes, copper, nickel, and RT{sub NDT{sub 0}} were increased so that RT{sub NDT}(2{sigma}) = 270{degree}F for the critical weld at 32 EFPY. This value of RT{sub NDT} corresponds, of course, to the NRC PTS-Rule screening criteria (10 CFR 5.61). This hypothetical plant'' was referred to as HBR-HYPO, and it was identical to HBR-2 in every respect except for the concentrations of copper and nickel and the value of RT{sub NDT{sub 0}} for the welds. 3 refs.

Research Organization:
Oak Ridge National Lab., TN (USA)
Sponsoring Organization:
NRC
DOE Contract Number:
AC05-84OR21400
OSTI ID:
6584413
Report Number(s):
CONF-9009273-2; ON: DE91000734
Country of Publication:
United States
Language:
English