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:
nation personnel may be expected while RPV nozzles are being manually examined. The probable percent increase in examination time or radiation exposure is impossible to estimate without field data and research effort. Requirements for reporting traveling indica- tions and indications associated with flaws larger than 1 inch may lead to an increase in occupational exposure in those cases in which the above indications are found and additional examination is required. The magnitude of this additional exposure canonly be assessed on a case-by-case basis. It should be noted that radiation levels at vessel nozzle regions are reported to range from 0.5 to 2.0 rem/hour. Total person-rem doses can be drastically reduced by shielding and local decontamination. The guide is not expected to have any adverse impact on other government agencies or the public. 1.3.4 Public No impact on the public can be foreseen. The only identifiable value is a slight acceleration in the review process. 1.4 Decision on Proposed Action The Office of Nuclear Reactor Regulation (NRR) has stated the need for this guide to help them and their consultants in evaluating the size and significance of the flaws detected during inservice examination to ensure the integrity of reactor pressure vessels between periods of examination. It would therefore be advisable to issue this guide. 2. APPROACH 2.1 Technical Alternatives Alternatives would include requiring the use of holography, synthetic aperture imaging, acoustic emission, neutron radiography, or a combination of the above during RPV inservice examination. 2.2 Procedural Alternatives One alternative is to leave the situation as it is. A second alternative is to request change of the ASME Code require- ments. Imposing inservice examination of RPV welds by the use of holography, synthetic aperture imaging technique, or acoustic emission, all of which are still in the stage of proto- type development and have not been proved effective for field use, would