Document: NRC Regulatory Guide
Document ID: a1541707-8144-409c-8842-4ea7d4b8ef4e
Document Type: regulatory_guide
Title: 10/2019 (Rev. 19)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1912/ML19128A244.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.147
CFR Part: 
CFR Title: 

Content:
quirements for Analytical Evaluation of Pipe Wall Thinning, Section XI (1) The use of Code Case N-597-3 for any degradation mechanisms other than flow-accelerated corrosion is not authorized unless an alternative is proposed and approved in accordance with 10 CFR 50.55a(z). (2) Use of Code Case N-597-3 to mitigate flow-accelerated corrosion is authorized subject to the following conditions: a. The Code Case must be supplemented by the provisions of the EPRI/Nuclear Safety Analysis Center Report (NSAC) report EPRI/NSAC-202L-2,“Recommendations for an Effective Flow Accelerated Corrosion Program,” issued April 1999 (Ref. 7), for developing the inspection requirements, the method of predicting the rate of wall-thickness loss, and the value of the predicted remaining wall thickness. As used in EPRI/NSAC-202L-R2, the term “should” is to be applied as “shall” (i.e., a requirement). b. Components affected by flow-accelerated corrosion to which this Code Case is applied must be repaired or replaced in accordance with the Construction Code of Record and the owner’s requirements or a later NRC-approved edition of Section III before the value of tp reaches the allowable minimum wall thickness, tmin, as specified in Figure-3622.1(a)(1) of this Code Case. Alternatively, use of the Code Case is subject to NRC review and approval in accordance with 10 CFR 50.55a(z). (3) For those components that do not require immediate repair or replacement, the rate of wall-thickness loss is to be used to determine a suitable inspection frequency so that repair or replacement occurs prior to reaching allowable minimum wall thickness, tmin. (4) The evaluation criteria in Code Case N-513-4 may be applied to Code Case N-597-3 for the temporary acceptance of wall thinning (until the next refueling outage) for moderate-energy Class 2 and 3 piping. (5) Code Case N-597-3 shall not be used to evaluate through-wall leakage conditions. 5/13E RG 1.147, Rev. 19, Page 15 CODE CASE NUMBER TABLE 2