Document: NRC Regulatory Guide
Document ID: 4a45938b-46f4-4b26-9191-2914fcf357f1
Document Type: regulatory_guide
Title: Inservice Inspection of Pressurized Water Reactor Steam Generator Tubes (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003740256.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.83
CFR Part: 
CFR Title: 

Content:
ceed the plugging limit should be taken out of service by plugging both ends of the tube, at the tube sheet with welded plugs. Various methods are used for plugging and welding. Plugs may be installed mechanically or explo sively, and welding may be performed manually, auto matically, or explosively. Experience has indicated that each steam generator design has critical areas (e.g., crevices, low-flow areas, and regions that allow steam blanketing) where attack and degradation of the steam generator tubes may occur even if secondary water chemistry is properly main tained. Mechanical damage to steam generator tubes may also occur in areas subject to flow-induced vibrations. Typically, the number of tubes in these critical areas is less than 20% of the total. The usual shop examination of tubing can be consid ered to serve as an adequate baseline examination. An onsite preservice inspection of the steam generator tubing should be performed in the absence of a documented shop or field examination. For plants now operating, the initial inspection should sample tubes on a random basis unless experience with similar designs and chemistry indicate critical areas. Subsequent inspec tions should concentrate on any critical areas identified so that most defective tubes will be found. This selection method can be expected to result in the ratio of tube defects found to total tubes inspected being consider ably higher than the ratio of defective tubes to total tubes in the steam generator. *Lines indicate substantive changes from previous issue. 1.83-2 C. REGULATORY POSITION A program for inservice inspection of steam generator tubing should be established and should include the following: .1. Access for Inspection a. Steam generators of pressurized water reactors should be designed to facilitate inspection of all tubes. b. Sufficient access should be provided to perform these inspections and to plug tubes as required. c. Pre-job planning should be undertaken to make