Pressurized thermal shock screening criteria re-evaluation effort - US industry activities

A joint project is under way between the US nuclear power industry and the US Nuclear Regulatory Commission (NRC) to re-evaluate the pressurized therm al shock (PTS) screening criteria as presently defined in title 10 of the C ode of Federal Regulations, 10 CFR 50.61. Advances in probabilistic risk as sessment (PRA), probabilistic fracture mechanics (PFM), thermal hydraulics (TH), and overall plant risk assessment are being incorporated into a compr ehensive program to establish a technical basis for revising the present sc reening criteria. US industry activities are being coordinated through the Reactor Pressure Vessel Integrity Issue Task Group (RPV Integrity ITG) of t he EPRI Materials Reliability Project (MRP). The EPRI MRP was formed in 199 8 to identify and address issues that could affect operability of major com ponents in pressurized water reactor (PWR) plants. Major activities are coo rdinated with the nuclear steam supply system (NSSS) vendors, the vendor ow ner's groups, The Nuclear Energy Institute (NEI), and the NRC. The MRP prov ides for a unified industry approach to resolution of technical and regulat ory issues related to PWR materials degradation. A major task under the Rea ctor Pressure Vessel Integrity Issue Task Group (RPV Integrity ITG) is to s upport industry activities associated with the pressurized PTS re-evaluatio n effort. This paper provides a brief overview of the EPRI MRP program, the RPV Integrity ITG, and industry activities associated with the PTS re-eval uation effort. (C) 2001 Elsevier Science Ltd. All rights reserved.