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Part 03 Environmental Report (Rev. 1) - Part 3 - Er - Chapter 2 - Environmental Description - Section 2.7.2 - Regional Air Quality
	ML18003A433
Person / Time
Site:	Clinch River
Issue date:	12/15/2017
From:	James Shea; Tennessee Valley Authority
To:	; Office of New Reactors
	Fetter A
References
	TVACLINCHRIVERESP, TVACLINCHRIVERESP.SUBMISSION.4, CRN.P.PART03, CRN.P.PART03.1
	Download: ML18003A433 (6)
	v • d • e

Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report 2.7.2-1 Revision 1 2.7.2 Regional Air Quality Existing air quality for the Clinch River Nuclear (CRN) Site and surrounding areas is presented in this subsection, along with potential air emissions sources associated with the construction and operation of two or more small modular reactors (SMRs). Existing air quality is defined by whether the U.S. Environmental Protection Agency (EPA) ambient standards are met.

The CRN Site is located in Roane County. Details of the CRN Site location are provided in Sections 2.1 and 2.2, which describe the 6-mile (mi) vicinity and 50-mi region surrounding the CRN Site.

2.7.2.1 Background Air Quality The Clean Air Act of 1977 (CAA), which was last amended in 1990, requires the EPA to set National Ambient Air Quality Standards (NAAQS) for pollutants considered harmful to public health and the environment. The EPA has set NAAQS for six criteria pollutants [carbon monoxide (CO), lead, nitrogen dioxide (NO2), ozone, sulfur oxides (SO2), particulate matter with a diameter of less than 10 microns (PM10), and particulate matter with a diameter of less than 2.5 microns (PM2.5)] for which air quality in an area is determined to be either in attainment or in nonattainment. Pollutant concentrations in nonattainment areas are greater than acceptable levels established by NAAQS, which indicates poor air quality. Attainment areas meet the NAAQS.

Table 2.7.2-1 provides the counties in Tennessee designated as of July 13, 2015 as nonattainment areas (NAAs).

Census Block Group 47-145-0307-2 is the portion of Roane County that is designated as nonattainment for PM2.5 (both the 1997 and 2006 standards). Figure 2.7.2-1 shows this nonattainment census block group is located approximately 6 mi west of the CRN Site. The portion of Roane County in which the CRN Site is located is in attainment for PM2.5 and all air pollutants. However, neighboring counties (Anderson, Blount, Knox, and Loudon) and part of Roane County (not including the CRN Site) are designated nonattainment for PM2.5. (Reference 2.7.2-1; Reference 2.7.2-2) Once a state implements mitigation measures to improve air quality in nonattainment areas and an area meets the ambient air quality standards and other re-designation requirements under the CAA, EPA can re-designate that area as a maintenance area. Maintenance areas are designated by pollutant. Table 2.7.2-2 identifies the locations in Tennessee, listed as maintenance areas.

The CAA and amendments identify areas worthy of added protection, designated as Prevention of Significant Deterioration (PSD) Class I areas. PSD Class I areas include national wilderness areas, memorial parks that exceed 2023.4 hectares (ha; 5000 acres [ac]), national parks that exceed 2428.1 ha (6000 ac), and international parks (Reference 2.7.2-3). The PSD Class I Areas closest to the CRN Site are the Great Smoky Mountains National Park (Gatlinburg, Tennessee), located approximately 31 mi to the east-southeast; the Joyce-Kilmer

Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report 2.7.2-2 Revision 1 Slickrock Wilderness Area (Graham County, North Carolina), located approximately 36 mi to the southeast; and the Cohutta Wilderness Area (Blue Ridge, Georgia), located approximately 61 mi to the south.

2.7.2.2 Projected Air Quality Generation of electricity associated with two or more SMRs would not be a source of criteria or toxic air pollutants. Supporting equipment such as cooling towers, emergency diesel generators, auxiliary boilers, combustion turbines and other potential sources emit criteria pollutants; however, these activities are not expected to be a significant source of emissions.

Potential air quality impacts for these sources are discussed in Subsection 5.8.1.2, including the projects area of influence. Subsection 5.8.1.2 also addresses potential air emissions of both criteria pollutants and greenhouse gases. Because the project is not located in a nonattainment area for any pollutant, the Clinch River (CR) SMR Project is not subject to Nonattainment New Source Review. In addition, supporting emissions data presented in Subsection 5.8.1.2 indicate that based on expected bounding CR SMR Project emissions values, the project is not expected to be a major source of air pollution under the Prevention of Significant Deterioration air regulations either.

Potential air emissions and mitigation measures associated with the preconstruction and construction phases are discussed in Subsection 4.4.1.2.

2.7.2.3 Restrictive Dispersion Conditions Atmospheric dispersion can be described as the horizontal and vertical transport and diffusion of pollutants released into the atmosphere. Horizontal and vertical wind dispersion is controlled primarily by variation in wind direction and wind speed, atmospheric stability, and the height of the mixing layer. In general, lower wind speeds represent less turbulent air flow, which is restrictive to both horizontal and vertical dispersion. Lower wind speeds also allow air contaminants to concentrate into a smaller volume of air. Wind direction tends to be more variable under lower wind speed conditions (which increases horizontal dispersion); however, under these conditions air pollutants may be recirculated within a limited area, thereby increasing air contaminant concentrations. Atmospheric stability is affected by the heating of the ground by the sun, which in turn heats the atmosphere from the ground up. Under unstable conditions (associated with warmer ground temperatures), dispersion is enhanced; under stable atmospheric conditions, dispersion is restricted. The height of the mixing layer, which depends on the vertical temperature profile, limits mixing of air contaminants (mixing occurs only up to the height of the mixing layer). Under unstable conditions and a lower mixing layer height, less atmosphere is available for mixing, and air contaminant concentrations generally increase.

Wind data, atmospheric stability, and mixing heights for the CRN Site, along with wind direction persistence and inversions, are discussed in more detail in Subsection 2.7.4.

Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report 2.7.2-3 Revision 1 2.7.2.4 References Reference 2.7.2-1. U.S. Environmental Protection Agency, Tennessee Nonattainment/Maintenance Status for Each County by Year for All Criteria Pollutants, Website:

http://www.epa.gov/oaqps001/greenbk/anayo_tn.html, January 30, 2015.

Reference 2.7.2-2. U.S. Environmental Protection Agency, EPA Approves Redesignation of Knoxville Area to Attainment for the 2008 8-Hour Ozone Standard, Website:

http://yosemite.epa.gov/opa/admpress.nsf/d0cf6618525a9efb85257359003fb69d/c0535b494c0 ee0be85257e81004f5475!opendocument, July 13, 2015.

Reference 2.7.2-3. U.S. Environmental Protection Agency, Visibility Maps of Protected Areas, Website: http://www.epa.gov/visibility/maps.html, May 31, 2012.

Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report 2.7.2-4 Revision 1 Table 2.7.2-1 Tennessee County Nonattainment Areas County NAAQS and Pollutant by Year NAA Area Name Anderson County 1997 PM2.5 2006 PM2.5 Knoxville, TN (Moderate)