Document: NRC Regulatory Guide
Document ID: c55ba6c5-aa2d-4ad6-aba2-2001e16524ab
Document Type: regulatory_guide
Title: Ultrasonic Testing of Reactor Vessel Welds During Preservice and Inservice Examinations (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1221/ML12216A015.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.150
CFR Part: 
CFR Title: 

Content:
racting for the beam width in the through-thickness direction obtained from the calibration hole (between 20 percent DAC points) that is at a depth similar to the flaw depth. If the indication exceeds 50 percent DAC, the size should be recorded by measuring the distance between 50 percent DAC levels without using the beam-width correction. The determined size should be the larger of the two. 6.2 Nontraveling Indications Nontraveling indications above 20 percent DAC level that persist for a scanning distance of more than 1 inch plus the beam spread between 20 percent DAC points (as defined by nonmandatory Appendix B, Article 4, Section V of the ASME Code, 1977 edition) should be considered significant. The size of these flaws should be determined by measuring the distance between points *at 50 percent DAC and between points at 20 percent DAC where the beam-width correction is made only for the 20 percent DAC size. The recorded size of the flaw would be the larger of the two determinations. If it can be adequately demon- strated that a nontraveling indication is from a geometric source (and not a flaw), there is no need to record that indication. The following information should also be recorded for indications that are reportable according to this regulatory position: a. Indications should be recorded at scan intervals no greater than one-fourth inch. b. The recorded information should include the indica- tion travel (metal path length)-and the transducer position for 10 percent, 20 percent, 50 percent, and 100 percent DAC and the maximum amplitude of the signal. 7. REPORTING OF RESULTS Records10 obtained while following the recommendations of regulatory positions 1.2, 3, 5, and 6, along with discus- sions and explanations, if any, should be kept available at the site for examination by the NRC staff. If the size of an indication, as determined in regulatory positions 6.1 or 6.2, equals or exceeds the allowable limits of Section XI of the ASME Code, the indications