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:
determined in part by the use of additional reflectors in the basic calibration block. b. A description of the technique used to qualify the effectiveness of the examination procedure, including, as a minimum, material, section thickness and reflectors. c. The best estimate of the por- tion of the volume required to be examined by the ASME Code that has not been effectively examined such as volumes of material near each surface because of near-field or other effects, volumes near inter- faces between cladding and parent metal, volumes shadowed by laminar material defects, volumes shadowed by part geometry, volumes inac- cessible to the transducer, volumes 1.150-15 affected by electronic gating, and volumes near the surface opposite the transducer.'* Sketches and/or descriptions of the tools, fixtures and component geometry which contribute to incomplete coverage should be included. I "°It should be noted that the licen- see is required to apply for relief from impractical ASME Code require- ments according to §50.55a of 10 CFR. If the licensee is committed to exa- mine a weld as per the inspection plan in the plant SAR, the licensee is required to file an amendment when the commitments made in the SAR cannot be met. d. Provide sketches of equipment (i.e., scanning mechanism and transducer holders) with reference points and necessary dimensions to allow a reviewer to follow the equipment's indication location scheme. e. When other volumetric tech- niques are used, a description of the techniques used should be included in the report. I 1.150-16 VALUE/IMPACT STATEMENT W 1. PROPOSED ACTION 1.1 Description The present inservice examination procedures for ultrasonic examination require improvement in order to consistently and reliably characterize flaws in reactor pressure vessel (RPV) welds and RPV nozzle welds. The apparent low level of the reproducibility: of detection, location, and characterization of flaws leads to lengthy discussions and delays in the licensing