Document: NRC Regulatory Guide
Document ID: 6f84e3bf-9ff3-49fb-a16a-0de3b89e6bc6
Document Type: regulatory_guide
Title: An Approach for Plant-Specific Risk-Informed Decisionmaking for Inservice Inspection of Piping (Rev. 2)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2103/ML21036A105.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.178
CFR Part: 
CFR Title: 

Content:
ts in terms of their contribution to risk, it is the responsibility of a licensee to ensure that the categorization of piping segments and the resulting inspection programs are consistent with the key principles and risk guidelines (e.g., core damage frequency (CDF) and large early release RG 1.178, Page 6 frequency (LERF)) addressed in RG 1.174). This guide augments the information presented in RG 1.174 by providing guidance specific to incorporating risk insights into ISI programs for piping. The NRC has recommended additional augmented inspection programs, implemented by the industry, to address generic piping degradation problems to preclude piping failure. Notable examples of augmented programs for piping inspections include the following topics: • intergranular stress-corrosion cracking of stainless steel piping in boiling-water reactors (BWRs) (Generic Letter 88-01, “NRC Position on Intergranular Stress Corrosion Cracking (IGSCC) in BWR Austenitic Stainless Steel Piping,” issued January 1988 (Ref. 15)) • thermal fatigue (NRC Bulletin 88-08, “Thermal Stresses in Piping Connected to Reactor Coolant Systems,” issued June 1988 (Ref. 16); NRC Bulletin 88-11, “Pressurizer Surge Line Thermal Stratification,” issued December 1988 (Ref. 17); and NRC Information Notice 93-20, “Thermal Fatigue Cracking of Feedwater Piping to Steam Generators,” issued March 1993 (Ref. 18)) • stress-corrosion cracking in pressurized-water reactors (PWRs) (NRC Bulletin 79-17, “Pipe Cracks in Stagnant Borated Water Systems at PWR Plants,” Revision 1, issued October 1979 (Ref. 19)) • service water integrity program (NRC Generic Letter 89-13, “Service Water Systems Affecting Safety-Related Equipment,” issued July 1989 (Ref. 20)) • flow-accelerated corrosion (FAC) in the balance of plant for both PWRs and BWRs (NRC Generic Letter 89-08, “Erosion/Corrosion-Induced Pipe Wall Thinning,” issued May 1989 (Ref. 21)) Augmented programs have generally been