Potential for Low Fracture Toughness and Lamellar Tearing in PWR Steam Generator and Reactor Coolant Pump Supports.

摘要

This report summarizes the work performed by the Nuclear Regulatory Commission staff and its contractor, Sandia Laboratories, leading to the resolution of Unresolved Safety Issue A-12, 'Potential for Low Fracture Toughness and Lamellar Tearing in PWR Steam Generator and Reactor Coolant Pump Supports.' It supersedes NUREG-0577, For Comment, dated October 1979. This report describes the technical issues that arose during a licensing review of two North Anna pressurized water reactors (PWRs), a generic technical study performed by Sandia Laboratories, and the staff's technical positions based on these studies. The safety issue is defined, and methods for demonstrating adequate fracture toughness are given. The staff has concluded that the lamellar tearing aspect of Unresolved Safety Issue A-12 is resolved.