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
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Section ID: RG-1.23
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Specify the minimum amount of data needed at docketing for 10 CFR Part 52 early site permit and combined license applications. The minimum amount of data needed at docketing for early site permit and combined license applications under 10 CFR Part 52 is similar to the minimum amount of data needed at docketing for operating license applications under 10 CFR Part 50. 5. Provide additional guidance for siting meteorological instruments (e.g., separation distance between wind sensors and obstructions to airflow such as buildings, trees, and nearby terrain; instrument boom length and orientation; avoidance of nearby heat and moisture sources such as cooling towers and parking lots; use of aspirated radiation shields for temperature sensors; use of heaters and wind shields for precipitation gauges). The agency adopted much of this enhanced guidance from ANSI/ANS-3.11-2005. 6. Delete the criterion for using standard deviation of horizontal wind direction (σθ) as a basis for classifying atmospheric stability. Vertical temperature difference is the preferred method for determining Pasquill stability classes at nuclear power plants for licensing purposes because it is an effective indicator for the worst case stability conditions (e.g., Pasquill stability classes E, F, and G), and certain Gaussian plume models endorsed by the NRC (such as the models referenced in Regulatory Guides 1.145 and 1.194) are based on empirically derived plume meander factors from field tracer studies that used ∆T to classify atmospheric stability. Alternative methods may be used to classify atmospheric stability if appropriate justification is provided. However, the use of alternative methods to classify atmospheric stability may require modifications of the models described in Regulatory Guides 1.145 and 1.194. Proposed Change Basis Appendix A to DG-1164, Page A-5 7. Add a criterion that precipitation should be measured at ground level near the base of the tower. Severe accident calculations