Document: NUREG-1555
Document ID: 16efba2d-597d-4734-84e7-046c257d75c3
Document Type: esrp
Title: HEAT-DISCHARGE SYSTEM
Source: NUREG-1555
Source URL: https://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1555/initial/
Revision Date: 2007-10
Chapter: 5
Section ID: 5.3.3
CFR Part: 
CFR Title: 

Content:
most apparent effects of heat dissipation systems on terrestrial ecosystems are those associated with cooling-tower or spray pond operation. These include the effects of vapor plumes, icing, and salt drift on the terrestrial ecosystems. The potential for bird collision with cooling towers should be addressed by the reviewer for ESRP 4.3.1. To date, at stations using once through cooling systems, no adverse impacts to terrestrial ecosystems have occurred that require mitigating actions. In circumstances where once through cooling is proposed, the analysis may terminate without further consideration unless unusual environmental circumstances make more analysis necessary. (1) Consider the impacts of drift deposition on plants. ` Drift deposition has the potential for adversely affecting plants, but the tolerance levels of native plants, ornamentals, and crops are not known with precision. ` General guidelines for predicting effects of drift deposition on plants suggest that many species have thresholds for visible leaf damage in the range of 10 to 20 kg/ha/mo of NaCl deposited on leaves during the growing season. ` These effects can be altered by the frequency of rainfall, humidity, type of salt, and sensitivity of species. ` Use maps of the site and vicinity showing drift isopleths that were produced by recognized drift- dispersion models to define areas of possible botanical injury. October 1999 5.3.3.2-5 NUREG-1555 ` Use an order-of-magnitude approach, as follows, to analyze operational impacts from salt drift: - Deposition of salt drift (NaCl) at rates of 1 to 2 kg/ha/mo is generally not damaging to plants. - Deposition rates approaching or exceeding 10 kg/ha/mo in any month during the growing season could cause leaf damage in many species. - Deposition rates of hundreds or thousands of kg/ha/yr could cause damage sufficient to suggest the need for changes of tower-basin salinities or a reevaluation of tower design, depending on the amount of land impacted and the