Document: NUREG-0800
Document ID: b07c8dd1-23f6-41f1-a3ba-aa378f9ea59a
Document Type: srp
Title: RISK-INFORMED INSERVICE INSPECTION
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0325/ML032510135.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.9.8
CFR Part: 
CFR Title: 

Content:
of ISI is to identify conditions, such as flaw indications, that are precursors to leaks and ruptures in pressure boundaries that may impact plant safety. The staff reviews the licensee’s bases for the assessment that the proposed change meets the intent of the ASME Code requirements. Additional augmented inspection programs to address generic piping degradation problems have been recommended by the NRC to preclude piping failure and implemented by the industry. Notable examples of augmented programs for piping inspections are to address intergranular stress corrosion cracking (IGSCC) of stainless steel piping in boiling water reactors (BWRs) (NRC Generic Letter 88- 01), thermal fatigue (NRC Bulletin 88-08, NRC Bulletin 88-11, NRC Information Notice 93-020), stress corrosion cracking in pressurized water reactors (PWR) (IE Bulletin 79-17), Service Water Integrity Program (NRC Generic Letter 89-13) and flow accelerated corrosion (FAC) in the balance of plant for both PWRs and BWRs (NRC Generic Letter 89-08). The manner in which the augmented inspection programs for piping are addressed is reviewed. I.2.2 Probabilistic Risk Assessment The scope, level of detail, and quality required of the PRA is commensurate with the emphasis that is put on the risk insights and on the role the PRA results play in the integrated decisionmaking process. If the justification for the change is based on well-founded traditional arguments supported by PRA insights, a limited PRA review may be warranted. However, if the justification for change is based on complex PRA arguments, the breadth and depth of the PRA review will be substantially greater. Only the parts of the PRA that are used to support the ISI change application need to be reviewed. I.2.2.1 Scope of Piping Systems The scope of piping included in the proposed RI-ISI program is reviewed. The current ISI requirements for nuclear power plant piping are specified in 10 CFR 50.55a, which incorporates, by reference, the