Document: NRC Regulatory Guide
Document ID: ad61f8a3-1cce-4446-9542-dcdda55c1ec6
Document Type: regulatory_guide
Title: Comprehensive Vibration Assessment Program for Reactor Internals During Preoperational and Initial Startup Testing + HISTORY - HISTORY 07/2015 – DG-1323 , Proposed Revision 4 03/2013 – Periodic Review of Revision 3 – No Issues Identified 11/2006 – DG-1163 , Proposed Revision 3 (Rev. 4)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1508/ML15083A390.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.20
CFR Part: 
CFR Title: 

Content:
nternals to differ from that of the initially designated prototypes made the basic prototype and non-prototype classifications difficult to apply, resulting in the need for time-consuming case-by-case resolution of reactor internal classifications and corresponding vibration assessment programs. Consequently, the original guidelines were refined in Revision 1 of RG 1.20 (dated June 1975) to incorporate items that would expedite NRC staff review of the applicant or licensee’s CVAP. Generally, this was accomplished by increasing the specificity of the guidelines for the vibration analysis, measurement, and inspection programs, as well as including guidelines for scheduling significant phases of the CVAP. In particular, Revision 1 of RG 1.20 expanded the previous classifications and outlined an appropriate CVAP for each class. In general, under certain conditions, the expanded classifications and corresponding programs allowed reactor internals to be used as “limited prototypes” with specific provisions. The expanded classifications made using this guide compatible and consistent with design and operating experience, at that time. Revision 2 of RG 1.20 (dated May 1976) retained the expanded reactor internal classifications. However, Revision 2 included various changes in the corresponding vibration assessment programs and the reporting of results, which were made because of substantive public comments and additional staff review. Revision 3 of RG 1.20 (dated March 2007) modified the overall vibration assessment program for reactor internals, and summarized expectations regarding the evaluation of potential adverse flow effects. DG-1323, Page 7 Revision 3 also included changes to address COL applications or applications that do not reference a certified reactor design. Finally, based on operating experience, Revision 3 provided new guidance for steam dryers in BWR plants and information that could be applied to monitoring programs for plant components outside the