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
CFR Part: 
CFR Title: 

Content:
��keyhole” protective action recommendation may not be appropriate. DG-1164, Page 11 A backup recording system (either analog or digital) may be used to provide a high assurance of valid data. Where analog data recording systems are used, wind speed and wind direction should be recorded on continuous trace strip charts. Other variables may be recorded on multipoint charts with a sampling rate of at least once per minute. The basic data should be compiled and archived as hourly values for use in historical climatic and dispersion analyses. Digital hourly values should consist of a sampling of data at intervals no longer than 60 seconds, and the mean values for the accumulated data should be determined using no less than 30 instantaneous values spaced equally over not less than a 15-minute period. The hourly values may be generated by using one 15-minute value per hour (if the same 15-minute period is used each hour) or by averaging all of the 15-minute values recorded during the hour. For precipitation, the hourly value should represent the total amount of precipitation (water equivalent) measured during the hour. Hourly maximum wind speed gust values may also be archived for use in the analysis of wind loading for the design of buildings and other structures. Appendix A shows the format for the electronic copy of the hourly database that should be submitted as a supplement to the application. The basic data should also be compiled into annual joint frequency distributions of wind speed and wind direction by atmospheric stability class. Table 3 gives an example of a suitable format for data compilation and reporting purposes. Similar tables of joint frequency distribution should be prepared for each of the other atmospheric stability classes.10 To aid in assessing the impact of plant operation on the environment, joint frequency distribution types of data summaries should be compiled, which will permit the description of the frequency and extent of fogging and