Document: NRC Regulatory Guide
Document ID: 29acb072-d497-44e6-ac1c-a053c0a468a0
Document Type: regulatory_guide
Title: Meteorological Monitoring Programs for Nuclear Power Plants + HISTORY - HISTORY DG-1164 , Third Proposed Revision 1, published 10/2006 Draft ES 926-4 , Second Proposed Revision 1, entitled "Meteorological Measurement Program for Nuclear Power Plants," published 04/1986 Draft SS 926-4 , First Proposed Revision 1, entitled "Meteorological Programs In Support of Nuclear Power Plants," published 09/1980 Revision 0, entitled "Onsite Meteorological Programs," was issued as Safety Guide 23
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0625/ML062540408.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.23
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CFR Title: 

Content:
ime display in the appropriate emergency response facilities (e.g., control room, technical support center, and emergency operations facility). The 15-minute averaged values should be calculated using at least 30 equally spaced samples. All the meteorological channels required for input to the dose assessment models should be available and presented in a format compatible for input to the models. Regulatory Guide 1.97, “Criteria for Accident Monitoring Instrumentation for Nuclear Power Plants,” Revision 4, issued June 2006, provides additional criteria for the display of meteorological data in control rooms. If the basis for any of the emergency action levels includes the monitoring of onsite meteorological conditions (e.g., the occurrence of measured hurricane-force winds onsite as a basis for declaring an Unusual Event), the tower and its instrumentation should be capable of surviving, monitoring, and displaying the meteorological condition. If the plant computer system collects wind speed, wind direction, and atmospheric stability data, these data should be submitted as inputs to the NRC ERDS as provided for in Section VI of Appendix E to 10 CFR Part 50. The applicant should have provisions in place to obtain representative meteorological data from alternative sources during an emergency if the site meteorological monitoring system is unavailable. 9. Documentation The safety analysis report should document the onsite meteorological measurements program, in accordance with 10 CFR 50.34(a)(1) and 50.34(b)(1). DG-1164, Page 13 Table 3. Example Joint Frequency Distribution of Wind Direction, Wind Speed, and Stability Class Site/Plant Name: Extremely Stable (∆T exceeds 4.0 EC/100 m) Pasquill Stability Class G Period of Record: Wind Direction Wind Speed (m/s) at Meter Level; ∆T between Meters and Meters <0.5 0.5– 1.0 1.1– 1.5 1.6– 2.0 2.1– 3.0 3.1– 4.0 4.1– 5.0 5.1– 6.0 6.1– 8.0 8.1– 10.0 >10.0 TOTAL N NNE NE ENE E ESE SE SSE S SSW SW WSW W