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:
with imperfec tions were found. In addition, the rest of the steam generators should'be inspected according to regulatory position C.4.c. c. If this additional inspection indicates that more than 10% of these additionally inspected tubes have detectable wall penetration (>20%) 'or one or more of these additionally inspected tubes has an indication in excess of the plugging limit, additional tubes (no less than 6% of the total tubes in the steam generator) in the area of the tube sheet array where tubes with imperfec tions were found should be inspected. 6. Inspection Intervals a. The first Inservice inspection of steam genera tors should be performed after 6 effective full power months but before 24 calendar months. b. Subsequent inservfce inspections should be not less than 12 nor more than 24 calendar months aftei the previous inspection. 'In all inspections, previously degraded tubes that exhibit significant (>10%) further wall penetration must be included in the 10%. c. Inspections may be made coincident with refueling outages or any shutdown for plant repair and maintenance in accordance with the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section XI.6 d. If two consecutive inspections, not including the preservice inspection, result in less than 10% of the tubes with detectable wall penetration (Ž20%) and no significant (Ž10%) further penetration of tubes with previous indications, the inspection frequency should be extended to 40-month intervals. If it can be demon strated through two consecutive inspections that previously observed degradation has not continued and no additional degradation has occurred, a 40-month inspection interval may be initiated. e. Unscheduled inspections should be conducted in the event of primary-to-secondary leaks exceeding technical specifications, a seismic occurrence greater than an operating basis earthquake,2 a loss-of-coolant accident requiring actuation of engineered safeguards, or a major