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:
uxiliary chemical feed system must be designed to maintain desired feedwater quality to each steam generator. Effective monitoring of water chemistry with in-line continuous analytical instrumentation supplemented by plant laboratory sampling analysis of steam, condensate return, and feedwater is necessary at all times during operation to ensure that water quality is not degraded below acceptable limits by such events as condenser inleakage or chemical feed system maloperation. Mechanical or flow-induced vibration can cause fret ting or fatigue damage to steam generator tubes, which could also lead to tube failures. A program of periodic inservice inspection of steam generators is essential to monitor the integrity of the tubing, particularly if there is evidence of mechanical damage or progressive deterioration caused by inade quate design, manufacturing errors, or chemical imbal ance. Inservice inspection of steam generator tubing can also provide useful information regarding the nature and cause of any tube degradation, thereby assisting the operator in taking proper and timely corrective measures. Inspection and repairs of steam generator tubing in operating plants cause some radiation exposure to personnel. Careful pre-job planning can assist in main taining radiation exposures as low as is reasonably achievable. Temporary shielding, decontamination, special tooling, jigs and fixtures for remote inspection and repair, and other design and procedural considera tions such as are outlined in Regulatory Guide 8.8, "Information Relevant to Maintaining Occupational Radiation Exposure as Low as Practicable (Nuclear Reactors)," should be used to the extent practical. The recommendations in this guide are applicable to current "typical" once-through and U-bend steam generators that have Ni-Cr-Fe or stainless steel tubing. The steam generator tubing is usually seamless, cold drawn, and annealed and is manufactured and tested in accordance with specifications of the