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:
enerators 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 American Society of Mechanical Engineers and the American Society for Testing and Materials. The initial quality of manufactured tubing is deter mined by hydrostatic, eddy current, and ultrasonic tests. The tube-to-tube-sheet welds are inspected visually and by dye penetrant, then finally leak tested. During reactor operation, steam generator tube leaks are detected by monitoring the secondary system for radioactivity and the presence of boron through instru. ment analysis of steam and blowdown samples. If leaks are present, they can usually be located by eday currept examination of suspect tubing. Eddy current examina tion is effective because it detects the presence of defect-caused variations in effective electrical conduc tivity and/or magnetic permeability of the material being tested. Because the .eddy current probing technique has excellent sensitivity in nonmagnetic materials, decreases in effective conductivity due to a discontinuity in a tube wall can be measured directly by increases in coil voltage in the probe. Special eddy current probes designed for scanning tubing from the inside have proved very effective in locating defect areas in steam generator tubes and for assessing the overall condition of the tubing in numerouj operating PWRs. Radiography is a supplemental method for inservice inspection of steam generator tubing. Although radi ography does not provide the speed and flexibility of eddy current methods, it can supplement eddy current testing for defect characterization on a limited basis. Leaking tubes, defective tubes, and tubes that exceed 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