Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Fracture mechanics assessment of PWR vessel integrity incorporating dynamic crack arrest data above 220 MPa radical m

Conference ·
OSTI ID:5741252

The present rules and criteria regarding the PTS issue, as established by the US Nuclear Regulatory Commission (NRC), are the PTS rule (Code of Federal Regulations, 1985) and Nuclear Regulatory Guide 1.154 (Regulatory Guide 1.154, 1987). The PTS rule specifics screening criteria in the form of limiting values of reference nil ductility temperature (RT{sub NDT}) of the reactor pressure vessel. Also, the PTS rule requires that a plant specific safety analysis must be performed for any plant that a utility seeks to operate beyond the screening criteria. Nuclear Regulatory Guide 1.154 provides guidance for utilities on how to perform the plant specific analysis. It references the IPTS study as an acceptable methodology for performing the probabilistic fracture mechanics portion of the plant specific analysis and specifies that the frequency of vessel failure due to PTS shall not exceed 5 {times} 10{sup {minus}6} failures per reactor year. Since the IPTS Program was completed, the Heavy Section Steel Technology (HSST) Program has conducted several large specimen fracture mechanics experiments which demonstrated that prototypical reactor pressure vessel steels are capable of arresting a crack propagating in the cleavage mode at fracture toughness values considerably above 220 MPa{radical}m, the implicit limit of the American Society of Mechanical Engineers (ASME) Code and the maximum value included in the IPTS studies. The purpose of this paper is to investigate the potential impact of the enhanced crack arrest data on the results of probabilistic fracture mechanics analyses. 12 refs., 5 figs.

Research Organization:
Oak Ridge National Lab., TN (USA)
Sponsoring Organization:
DOE; USDOE, Washington, DC (USA)
DOE Contract Number:
AC05-84OR21400
OSTI ID:
5741252
Report Number(s):
CONF-910817-9; ON: DE91009916
Country of Publication:
United States
Language:
English