Document: NUREG-0800
Document ID: bb1a5a83-5b12-456c-b141-1e450c066cff
Document Type: srp
Title: ONSITE METEOROLOGICAL MEASUREMENTS PROGRAM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1818/ML18183A446.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.3.3
CFR Part: 
CFR Title: 

Content:
erations, the positions of the primary and, if applicable, backup meteorological towers should have been selected with this general objective in mind. Examination of topographical maps, that have been modified to show the likely finished plant grade, a site visit, and professional judgment on airflow patterns are used to determine and evaluate the representativeness of the pre- operational and, if different, operational phase tower location(s). The proposed layout of plant structures, including structure heights, is examined for potential influence on meteorological measurements. Wind sensors should be located at least 10 obstruction heights away from the obstruction to airflow in order to minimize this influence. In those 2.3.3-11 Draft Revision 4 – September 2018 situations where one or more natural draft cooling towers are being utilized as the normal plant heat sink, wind sensors can be located closer, but should be at least five times the maximum width of the cooling tower structure from the cooling tower, to preclude the meteorological tower from being located a significant distance from the reactor. The distance is normally acceptable because the rounded and sloping characteristics of a hyperbolic cooling tower are more aerodynamically smooth and streamlined as compared to block-shaped structures and are therefore expected to have shorter building wake effects downwind. Precipitation gauges should be equipped with a wind deflector shield to improve gauge collection efficiency and may be equipped, where necessary, with heater devices to melt frozen precipitation. b. Meteorological Sensors The type and performance specifications of the sensors are evaluated. Manufacturers' specifications and the applicant’s operating experience with these sensors are considered in evaluating their adequacy with respect to channel accuracy and the potential for acceptable data recovery. The suitability of the specific type of sensor for use in the environmental conditions at