Document: NRC Regulatory Guide
Document ID: 55b1f520-7682-43fa-a5c3-254f661dcc82
Document Type: regulatory_guide
Title: Nondestructive Examination of Tubular Products
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1306/ML13064A108.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.66
CFR Part: 
CFR Title: 

Content:
oped tb, scanning in the transverse (circumferential) tdieclittor. l lowevet, transversw scanning is not ideal for resolving defects oriented in other directions. As a consequence, when pipe or tubing is examined using transverse scanning and axial standard defects, defects of unacceptable size with unfavorable orientation may appear to be smaller than the reference standard and thus escape detection. To adequately detect circuinferentia! defects, it is necessary to scan in the axial directidn with equipment calibrated using circum icrent ial notches. lFurther, scanning should be performed in both axial and both circumferential directions for optimum detection of defects oriented in directions not normal to the ' surface. This four-way scanning may be accomplished by separate passes of the pipe through the examination equipment in each direction (back and forth) or by a single pass through equipment containing four complete and independent channels of instrumentation. Eddy-Current Examination. Eddy-current examination may he used as an alternative to ultrasonic examination for thin-walled pipe and tubing. However, this method should be limited to materials with uniform magnetic proper ties (variability in magnetic properties may result from a variation in the degree of cold work in the material due to fabrication) and to pipe and tubing of appropriate sizes and thicknesses. Since the limiting size and thickness may be affected by such variables as coil design, frequency, material properties, and instrunmentation, these limitations should be established by the ability to resolve standard notches on both outside and inside surface of the reference specimen. Examination of Fittings. To the degree feasible, fittings should be examined using a volumetric examination method. Ultrasonic examination is preferred when applicable, but radiographic examination using appropriate techniques will also detect unacceptable defects. The use of these techniques may be limited by