Document: NUREG-0800
Document ID: 07d0f658-6bc5-4c2f-945b-45ffacf5d379
Document Type: srp
Title: ONSITE METEOROLOGICAL MEASUREMENTS PROGRAM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0636/ML063600394.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.3.3
CFR Part: 
CFR Title: 

Content:
wind speed at two levels, ambient air temperature difference between two levels, temperature, precipitation, and atmospheric moisture (at sites where water vapor is emitted, as from cooling towers or spray ponds). 2.3.3-8 Revision 3 - March 2007 a. Instrument Siting Instrument types, heights, and locations are compared generally to the position stated in Regulatory Guide 1.23. Detailed review procedures follow. (1) Local Exposure of Instruments The local exposure of the wind and temperature sensors is reviewed to ensure that the measurements will represent the general site area. A determination is made whether the tower which supports the sensors will influence the wind or temperature measurements. Professional experience and studies have shown that wind sensors should be mounted on booms such that the sensors are at least two tower widths away from an open-latticed tower. For temperature sensors, mounting booms need not be as long as those for wind sensors but must be unaffected by thermal radiation from the tower itself. No temperature sensors may be mounted directly on stacks or closed towers. Mounting booms for all sensors should be oriented normal to the prevailing wind at the site. A determination is made whether the terrain at or near the base of the tower will unnaturally affect the wind or temperature measurements. Heat reflection characteristics of the surface underlying the meteorological tower (grass, soil, gravel, paving, etc.) are estimated to ensure that localized influences on measurements are minimal. The position, size, and materials used in the construction of the recorder shack and nearby trees are also examined for potential localized influence on the measurements. (2) General Exposure of Instruments Since the objective of the instrumentation is to provide measurements which represent the overall site meteorology without plant structure interference, the tower position(s) should have been selected with this general objective in mind.