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:
rly shielded and, if possible, routed through reactor penetrations that do not include electrical supply lines. g. Data acquisition systems need to be calibrated to ensure that signals are not altered by data acquisition cards, cabling, or other mechanisms. In-plant measurements will include data noise (for example, from power cables) that can affect benchmarking. It is acceptable to use noise reduction techniques, provided they do not lead to excessive signal reduction and unreasonable data. Electrical signals may be removed using narrow-band filtering, provided the notch filters are not wider than necessary, removing actual signals near the electrical frequencies. When notch filtering is used, the subsequent structural dynamic analyses need to include frequency shifting of the loading to ensure that reasonable loads are applied to all structural resonances. It is also acceptable to add broad-band noise to the notch-filtered frequency bands to avoid non-physical “dips” in the spectral representation of the time signals. If used, the added noise needs to be comparable to signals at adjacent frequencies. If broad-band noise filtering techniques are applied, the applicant/licensee needs to illustrate that excessive signal reduction does not occur. Coherence processing and wavelet noise reduction are both reasonable filtering techniques of broad-band noise. 2.2.3 Vibration Measurement Program Documentation The vibration measurement program should include a description of the following systems, plans, and acceptance criteria, addressing the measurement and data issues discussed in Sections C.2.2.1 and C.2.2.2: a. Guidance on instrumentation and data acquisition and reduction system: The instrumentation and data acquisition and reduction system needs to include the following: (1) transducer types and their specifications, including applicable frequency and amplitude ranges; (2) transducer positions to monitor significant lateral, vertical, and torsional structural