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:
s performed manually and data are not recorded on tape, this position will mean extra examination time and increased radiation exposure to the examiners. Increase in dollar cost and radiation exposure will again depend on the number, size, and complexity of indications, and there are no bases or data available to estimate this increase. 6.2 Nontraveling Indications This position also recommends the recording of nontravel- ing indications above 20 percent DAC level that persist for a distance of more than 1 inch plus the beam spread. According to NB-5320, Radiographic Acceptance Standards, Section III, Division I, ASME Code, 1977 edition, flaws, larger than 3/4 inch for weld thicknesses above 2-1/4 inches are not acceptable. Because of this requirement, it is expected that no flaws larger than 3/4 inch in length are present in the RPV welds, and if indications are detected that suggest flaws larger than 3/4 inch, there is a strong possibility that these may be service-induced flaws. Service- induced flaws are rare in RPV w,-lds, and it is therefore not expected that additional indi -,ns would have to be recorded because of this position. However, if such indica- tions (over 1 inch) are detected, examination time for automated recording and examination time plus radiation exposure for manual UT examinations will be increased. There are no rational bases or data available to estimate the impact of regulatory position 6.2. 7. REPORTING OF RESULTS This position recommends that the areas required to be examined by the ASME Code that have not been effectively examined and an estimate of error band in sizing the flaws I 4 I 1.150-22 should be brought to the attention of the NRC when the results are reported. This effort may take about 5 hours in reportwriting time. 8. IMPLEMENTATION It should be noted that the recommendations of this guide are not intended to apply to those preservfce examination tests already completed. However, the licensees may consider repeating their