Document: NRC Regulatory Guide
Document ID: e5306f4f-dc8c-4f60-a71c-af7ad4080384
Document Type: regulatory_guide
Title: Aquatic Environmental Studies for Nuclear Power Stations + HISTORY - HISTORY 12/2014 – DG-4023 -Proposed New Guide
Source: NRC Regulatory Guide Division 4
Source URL: https://www.nrc.gov/docs/ML1318/ML13186A085.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-4.24
CFR Part: 
CFR Title: 

Content:
ng whether alternative energy sources requiring new generating capacity are competitive with the proposed energy source. RG 4.2 identifies alternative energy sources requiring new generating capacity. Nuclear, coal, natural gas, and a combination of alternatives are the most commonly considered alternative energy sources for new baseload power generating capacity; these alternative energy sources are normally compared under the assumption that they would be developed on the proposed site. However, green energy alternatives, such as wind power, solar power, and others, are becoming more efficient and should be considered when possible. For the purposes of this comparison, analysts would develop the combination of alternatives on the proposed site unless otherwise stated. No specific aquatic ecology evaluation criteria reflect competitiveness between the alternative energy sources and proposed source. Instead, aquatic resources potentially affected by each energy alternative typically are described and compared at a coarse level of resolution (e.g., use of previously disturbed versus undisturbed habitat), including quantified data when possible. Heat Dissipation System Design Alternatives Support Aquatic ecology is a factor in assessing whether a heat dissipation system design alternative is environmentally preferable to the proposed system. Heat dissipation systems for new facilities normally include closed-cycle systems or systems that use an off-channel reservoir because a once-through system would lack compliance with CWA regulations (Ref. 20). A closed-cycle system usually uses one or more mechanical draft wet cooling towers, natural draft cooling towers, hybrid wet/dry cooling towers, or spray ponds. A cooling system can use an off-channel reservoir or cooling pond, with or without assistance of a cooling tower, as long as the water usage rates comply with the CWA. Regardless of the type of closed- cycle system, closed-cycle cooling consumes more water than