ML18003A442
| ML18003A442 | |
| 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: ML18003A442 (21) | |
Text
Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report 2.7.5-1 Revision 1 2.7.5 Short-Term Diffusion Estimates Short-term diffusion estimates are developed in support of evaluating postulated accidental releases of radioactive material from the Clinch River (CR) Small Modular Reactor (SMR)
Project. The consequence of a design basis accident in terms of personnel exposure is a function of the atmospheric dispersion conditions around the Clinch River Nuclear (CRN) Site.
Atmospheric dispersion consists of two components: 1) atmospheric transport, or the downwind movement of effluents through the atmosphere; and 2) atmospheric diffusion, or the spread of effluents away from the plume centerline. Atmospheric dispersion conditions are represented by relative air concentration (/Q) values. This subsection describes the development of conservative short-term atmospheric diffusion estimates for receptors located on the Exclusion Area Boundary (EAB) and the outer boundary of the Low Population Zone (LPZ).
2.7.5.1 Purpose and Background According to Title 10 of the Code of Federal Regulations (10 CFR) 100.11, the limiting design basis fission product release and site meteorological conditions should be used to derive an exclusion area, low population zone, and a population center distance. To demonstrate compliance with 10 CFR Part 100, it is necessary to consider doses for various time periods immediately following the onset of a postulated accident at the EAB and for the duration of exposure for the LPZ.
As a result, estimates of atmospheric dispersion, expressed as /Q, were calculated for accidental releases from the CRN Site for specified time intervals at the EAB and the LPZ, as required under 10 CFR 100 and 10 CFR 50.
2.7.5.2 Calculation Methodology and Assumptions The atmospheric dispersion calculations were performed using the PAVAN computer program, NUREG/CR-2858, PAVAN: An Atmospheric-Dispersion Program for Evaluating Design-Basis Accidental Releases of Radioactive Materials from Nuclear Power Stations, which was developed and is used by the U.S. Nuclear Regulatory Commission (NRC). The PAVAN program implements the guidance provided in NRC Regulatory Guide (RG) 1.145, Atmospheric Dispersion Models for Potential Accident Consequence Assessments at Nuclear Power Plants.
The PAVAN model calculates X/Q values based on the theory that material released to the atmosphere are normally distributed (Gaussian) about the plume centerline. Therefore, a straight-line trajectory is modeled between the point of release and distances for which /Q values are calculated in accordance with NUREG/CR-2858 and NRC RG 1.145.
NRC RG 4.7, General Site Suitability Criteria for Nuclear Power Stations, states that for site approval, each applicant should collect at least one year of meteorological information that is representative of the site conditions for calculating radiation doses resulting from the release of fission products as a consequence of a postulated accident. NRC RG 1.23 recommends using meteorological data from a consecutive 24-month period. Two full years (June 1, 2011 through
Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report 2.7.5-2 Revision 1 May 31, 2013) of CRN Site-specific meteorological tower data were used as input to the PAVAN code. Meteorological data were input as joint frequency distributions (JFDs), in percent frequency, of wind direction and wind speed by atmospheric stability class. Stability classes were based on the classification system given in Table 1 of NRC RG 1.23, and are listed in Table 2.7.5-1 herein.
Validated data from the lower meteorological tower level (10-meters [m]) of the CRN Sites meteorological monitoring program were used to prepare JFDs for the PAVAN modeling. Of the 17,544 hours0.0063 days <br />0.151 hours <br />8.994709e-4 weeks <br />2.06992e-4 months <br /> (hr) of possible data, 17,380 hr had valid data combinations of wind speed, wind direction, and stability class. The resulting data recovery was 99.07 percent, well above the 90 percent data recovery required by NRC RG 1.23. Calms hours were distributed into the first wind speed category in the JFDs, based on this PAVAN input option. Thirteen wind speed categories were defined in the JFDs and used in the modeling. The wind speed categories used in the PAVAN analysis are shown in the JFD tables; the JFD tables for each stability class are given in Tables 2.7.5-2 through 2.7.5-8. For the two years of data modeled, there were no hourly recordings of wind speed greater than 18.0 miles per hour (mph; 8.0 miles per second
[m/s]). The percent occurrence of hours for each wind direction is shown in Table 2.7.5-9, and the percent occurrence of hours in each stability class is given in Table 2.7.5-10.
Using the JFDs, PAVAN provides the /Q values as a function of direction for various time periods at the EAB and the LPZ. According to NRC RG 4.7, an applicant is required by Subpart A of 10 CFR Part 100 (100.11) and Subpart B of 10 CFR Part 100 (100.20) to designate an exclusion area and to have authority to determine all activities within that area, including removal of personnel and property. The exclusion area is required to be of such a size that an individual assumed to be located at any point on its boundary would not receive a radiation dose in excess of 25 rem total effective dose equivalent (TEDE) over any 2-hr period following a postulated fission product release. The required exclusion area size involves consideration of the atmospheric dispersion characteristics of the site as well as plant design.
NRC RG 1.145 requires that, for each of the 16 compass sectors, the distance to the EAB should be the minimum distance between the effluent release point and the EAB within a 45-degree sector centered on the compass direction of interest. For conservatism and simplicity, the effluent release point is evaluated as a circular effluent release boundary (ERB) that encloses potential release points from the nuclear island as shown in Figure 2.7.5-1. A circular analytical EAB is established 1100 ft (335 m) from the ERB. For X/Q modelling (Table 2.7.5-11), the analytical EAB is used as a bounding representative distance to the EAB.
To account for multiple units on site, nuclear islands are positioned at multiple locations within the power block area with associated ERBs and EABs as shown in Figure 2.7.5-2 (note that although the nuclear islands for vendors 1 and 4 are depicted in the figure, the nuclear islands, associated ERBs, and analytical EABs for vendors 1, 2, 3, and 4 fit within the EAB ellipse). The analytical EABs can be encompassed by an ellipse fixed completely within the CRN Property boundary, i.e. the actual EAB (Figure 2.7.5-2), which demonstrates that dispersion factor computations are conservative.
Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report 2.7.5-3 Revision 1 The site center point is determined as the centerline midpoint of the EAB ellipse (Figure 2.7.5-2). The ellipse has a short axis of 0.326 mi (524 m) from the site center point and long axis of 0.535 mi (864 m) from the center point.
According to NRC RG 4.7, an applicant is also required by 10 CFR Part 100 to designate an area immediately beyond the exclusion area as a LPZ. The size of the LPZ must be such that the distance to the nearest boundary of a densely populated center containing more than about 25,000 residents (population center distance) must be at least one and one-third times the distance from the reactor to the outer boundary of the LPZ. The boundary of the population center should be determined upon consideration of population distribution, not political boundaries. In addition, the LPZ must be of such a size that an individual located on its outer radius for the course of the postulated accident (assumed to be 30 days) would not receive a radiation dose in excess of 25 rem TEDE.
The LPZ is defined by a circular area with a radius of 1-mile (1609 m), centered on the site as shown in Figure 2.7.5-3.
Other plant specific data considered for PAVAN includes minimum building cross-sectional area, building height, and meteorological tower height at which the wind speed was measured (NUREG/CR-2858). These are listed in Table 2.7.5-12. The building height and minimum cross-sectional area are used in the determination of building wake effects. Building cross-sectional area is defined in NRC RG 1.145 as the smallest vertical-plane cross-sectional area of the containment structure, in square meters (sq m). NRC RG 1.111, Methods for Estimating Atmospheric Transport and Dispersion of Gaseous Effluents in Routine Releases from Light-Water-Cooled Reactors, identifies the tallest adjacent building, either up-or downwind from the release point(s), as appropriate for use. Because the dose calculations for the EAB and LPZ are both located beyond the building wakes significant zone of influence, the height and cross-sectional area have less effect on X/Q values. Therefore, for conservatism, no building wake credit was used in the PAVAN model (e.g., the building height and cross-sectional area were both set to zero in the model).
Based on NRC RG 1.145, a ground release includes release points that are effectively less than two and one-half times the height of adjacent solid structures. Compared to an elevated release, a groundlevel release usually results in higher groundlevel concentrations at downwind receptors due to the plume centerline being at groundlevel. Because the groundlevel release scenario provides a bounding case, elevated releases are not considered in this application.
The meteorological tower height used in PAVAN is the height above ground level at which the wind speed was measured (NUREG/CR-2858). For a groundlevel release, the lower wind speed and direction measurement height of 9.78 m is used (Table 2.7.5-12).
Because a groundlevel release scenario provides the most conservative X/Q values at the EAB, a groundlevel release was used in the modeling. As detailed in NRC RG 1.145, Section 1.3.1, for release modes that are effectively lower than two and one-half times the height of adjacent
Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report 2.7.5-4 Revision 1 solid structures (ground-release mode), two sets of meteorological conditions are treated differently in order to consider the effects of building wake mixing and plume meander (NUREG/CR-2858).
During neutral (D) or stable (E, F, or G) atmospheric stability conditions when the wind speed is less than 6 m/s, horizontal plume meander is considered. The PAVAN model (NUREG/CR-2858) calculates the relative concentration (/Q) values through the selective use of the following set of equations for groundlevel relative concentrations at the plume centerline.
=
Equation 1
=
()
Equation 2
=
(
)
Equation 3 Where:
/Q = centerline groundlevel relative concentration (sec/m3).
y = lateral plume spread as a function of atmospheric stability and distance (m).
z = vertical plume spread as a function of atmospheric stability and distance (m).
A = minimum building vertical-plane cross-sectional area (m2).
10 = average wind speed at 10 m above plant grade (m/s).
y = lateral plume spread with plume meander and building wake effects (m), as a function of atmospheric stability, wind speed, and distance.
The PAVAN model calculates /Q values using Equations 1, 2, and 3. The model compares the values from Equations 1 and 2, and the higher value is selected. This value is then compared with the value from Equation 3, and the lower value of these two is selected as the appropriate
/Q value.
During unstable (A, B, or C) atmospheric stability and / or 10-m level wind speeds of 6 m/s or more, plume meander (Equation 3) is not considered. The higher value calculated from Equation 1 or 2 is used as the appropriate /Q value.
NRC RG 1.145 requires that the X/Q values at the EAB and LPZ boundaries be calculated from the sector-independent, 50-percent overall site X/Q.
Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report 2.7.5-5 Revision 1 2.7.5.3 Results and Conclusions The 50 percent X/Q results for the SMR release zone, based on the two years of CRN Site-specific meteorological data (June 2011 through May 2013), are given in Table 2.7.5-13.
Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report 2.7.5-6 Revision 1 Table 2.7.5-1 Classification of Atmospheric Stability Stability Classification Pasquill Categories Temperature change with height (°C/100m)
Extremely unstable A
T -1.9 Moderately unstable B
-1.9 < T -1.7 Slightly unstable C
-1.7 < T -1.5 Neutral D
-1.5 < T -0.5 Slightly stable E
-0.5 < T 1.5 Moderately stable F
1.5 < T 4.0 Extremely stable G
T > 4.0 Note: Based on Table 1 in NRC RG 1.23.
Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report 2.7.5-7 Revision 1 Table 2.7.5-2 Joint Frequency Distribution (Hours) of Wind Speed and Direction by Atmospheric Stability Class - Stability Class A June 1, 2011 to May 31, 2013 WIND DIRECTION WIND SPEED (MPH)
CALM 0.50 1.10 1.70 2.20 2.80 3.40 4.50 6.70 8.90 11.20 13.40 18.00
>18.00 TOTAL N
0 0
0 1
0 3
3 9
16 2
0 0
0 0
34 NNE 0
0 0
1 1
4 10 23 23 0
0 0
0 0
62 NE 0
0 0
0 3
5 4
22 37 5
0 0
0 0
76 ENE 0
0 0
2 1
2 3
13 19 9
0 0
0 0
49 E
0 0
0 0
1 0
0 7
4 0
0 0
0 0
12 ESE 0
0 0
0 3
0 0
3 3
0 0
0 0
0 9
SE 0
0 0
0 0
2 0
1 0
0 0
0 0
0 3
SSE 0
0 0
1 0
0 1
0 2
1 0
0 0
0 5
S 0
0 0
0 2
0 0
0 0
0 0
0 0
0 2
SSW 0
0 0
1 1
0 0
1 0
0 0
0 0
0 3
SW 0
0 0
0 1
1 1
1 1
1 0
0 0
0 6
WSW 0
0 0
1 1
3 0
8 9
9 2
0 0
0 33 W
0 0
0 0
0 1
1 4
14 6
4 4
1 0
35 WNW 0
0 0
0 0
0 0
1 9
18 5
3 1
0 37 NW 0
0 0
1 2
0 1
6 21 48 23 4
0 0
106 NNW 0
0 0
1 0
1 0
5 9
4 0
0 0
0 20 Subtotal 0
0 0
9 16 22 24 104 167 103 34 11 2
0 492 Notes:
- 1.
JFDs based on 17380 total hours of valid wind direction-wind speed-stability observations.
- 2.
Stability based on T between 8.44 and 59.22 meters (T -1.9°C/100 M).
- 3.
Total hours of valid wind direction and wind speed in Stability Class A = 492.
- 4.
Wind speed, direction measured at 9.78 meters; mean wind speed = 5.73 mph.
- 5.
Totals and subtotals are obtained from unrounded numbers.
Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report 2.7.5-8 Revision 1 Table 2.7.5-3 Joint Frequency Distribution (Hours) of Wind Speed and Direction by Atmospheric Stability Class - Stability Class B June 1, 2011 to May 31, 2013 WIND DIRECTION WIND SPEED (MPH)
CALM 0.50 1.10 1.70 2.20 2.80 3.40 4.50 6.70 8.90 11.20 13.40 18.00
>18.00 TOTAL N
0 0
0 0
1 3
7 9
9 0
0 0
0 0
29 NNE 0
0 0
0 0
1 12 20 5
0 0
0 0
0 38 NE 0
0 0
0 1
8 12 24 36 3
0 0
0 0
84 ENE 0
0 0
0 0
5 7
10 16 1
0 0
0 0
39 E
0 0
0 0
0 0
5 12 8
0 0
0 0
0 25 ESE 0
0 0
0 0
1 1
6 1
0 0
0 0
0 9
SE 0
0 0
0 0
1 2
1 0
0 0
0 0
0 4
SSE 0
0 0
0 0
0 2
7 5
0 0
0 0
0 14 S
0 0
0 0
0 0
3 5
10 0
1 2
0 0
21 SSW 0
0 0
0 0
0 1
2 4
1 0
0 0
0 8
SW 0
0 0
0 0
0 2
11 13 4
0 0
0 0
30 WSW 0
0 0
0 0
1 8
23 41 18 5
1 0
0 97 W
0 0
0 0
0 1
3 18 14 2
1 2
1 0
42 WNW 0
0 0
0 0
0 4
7 20 17 6
2 1
0 57 NW 0
0 0
0 0
0 5
12 26 31 10 1
0 0
85 NNW 0
0 0
0 0
0 4
10 11 3
0 0
0 0
28 Subtotal 0
0 0
0 2
21 78 177 219 80 23 8
2 0
610 Notes:
- 1.
JFDs based on 17380 total hours of valid wind direction-wind speed-stability observations.
- 2.
Stability based on T between 8.44 and 59.22 meters (-1.9 < T -1.7°C/100 M).
- 3.
Total hours of valid wind direction and wind speed in Stability Class B = 610.
- 4.
Wind speed, direction measured at 9.78 meters; mean wind speed = 5.17 mph.
- 5.
Totals and subtotals are obtained from unrounded numbers.
Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report 2.7.5-9 Revision 1 Table 2.7.5-4 Joint Frequency Distribution (Hours) of Wind Speed and Direction by Atmospheric Stability Class - Stability Class C June 1, 2011 to May 31, 2013 WIND DIRECTION WIND SPEED (MPH)
CALM 0.50 1.10 1.70 2.20 2.80 3.40 4.50 6.70 8.90 11.20 13.40 18.00
>18.00 TOTAL N
0 0
0 0
3 7
15 6
13 0
0 0
0 0
44 NNE 0
0 0
1 0
13 12 21 3
0 0
0 0
0 50 NE 0
0 0
1 6
13 23 26 10 1
0 0
0 0
80 ENE 0
0 0
1 5
8 12 16 9
1 0
0 0
0 52 E
0 0
0 1
2 4
11 12 5
0 0
0 0
0 35 ESE 0
0 0
0 3
6 6
9 3
0 0
0 0
0 27 SE 0
0 0
0 2
8 2
6 5
0 0
0 0
0 23 SSE 0
0 0
0 1
3 10 4
2 1
0 2
0 0
23 S
0 0
0 0
1 4
4 13 15 4
2 1
0 0
44 SSW 0
0 0
0 1
6 9
12 12 3
0 0
0 0
43 SW 0
0 0
0 1
10 14 26 43 12 0
0 0
0 106 WSW 0
0 0
0 0
9 33 60 70 13 5
1 0
0 191 W
0 0
0 0
2 4
27 34 35 7
6 3
0 0
118 WNW 0
0 0
0 1
4 10 21 26 15 4
2 0
0 83 NW 0
0 0
0 0
1 11 14 38 20 7
0 0
0 91 NNW 0
0 0
0 2
4 4
9 8
4 3
0 0
0 34 Subtotal 0
0 0
4 30 104 203 289 297 81 27 9
0 0
1044 Notes:
- 1.
JFDs based on 17380 total hours of valid wind direction-wind speed-stability observations.
- 2.
Stability based on T between 8.44 and 59.22 meters (-1.7 T -1.5°C/100 M).
- 3.
Total hours of valid wind direction and wind speed in Stability Class C = 1044.
- 4.
Wind speed, direction measured at 9.78 meters; mean wind speed = 4.54 mph.
- 5.
Totals and subtotals are obtained from unrounded numbers.
Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report 2.7.5-10 Revision 1 Table 2.7.5-5 Joint Frequency Distribution (Hours) of Wind Speed and Direction by Atmospheric Stability Class - Stability Class D June 1, 2011 to May 31, 2013 WIND DIRECTION WIND SPEED (MPH)
CALM 0.50 1.10 1.70 2.20 2.80 3.40 4.50 6.70 8.90 11.20 13.40 18.00
>18.00 TOTAL N
0 1
14 57 33 27 17 22 21 2
0 0
0 0
194 NNE 0
0 6
53 49 39 25 42 11 0
0 0
0 0
225 NE 0
0 16 41 55 65 77 82 71 3
1 0
0 0
411 ENE 0
0 12 42 38 59 54 71 68 8
1 1
0 0
354 E
0 1
8 19 42 33 29 21 10 1
0 0
0 0
164 ESE 0
0 6
19 15 15 13 12 5
0 0
0 0
0 85 SE 0
0 6
10 17 21 19 10 1
1 0
1 0
0 86 SSE 0
0 4
9 12 25 11 12 10 4
7 1
0 0
95 S
0 0
3 13 23 37 44 51 56 30 25 7
3 0
292 SSW 0
1 8
16 23 39 41 44 49 6
0 0
0 0
227 SW 0
0 2
14 38 59 75 123 116 29 4
0 0
0 460 WSW 0
0 0
16 54 95 93 219 254 83 29 8
0 0
851 W
0 0
13 34 48 79 87 132 99 46 31 20 1
0 590 WNW 0
0 10 43 42 72 49 98 140 79 36 9
4 0
582 NW 0
0 19 48 43 58 48 85 139 75 35 6
0 0
556 NNW 0
0 16 41 30 33 30 27 35 11 4
0 0
0 227 Subtotal 0
3 143 475 562 756 712 1051 1085 378 173 53 8
0 5399 Notes:
- 1.
JFDs based on 17380 total hours of valid wind direction-wind speed-stability observations.
- 2.
Stability based on T between 8.44 and 59.22 meters (-1.5 < T -0.5°C/100 M).
- 3.
Total hours of valid wind direction and wind speed in Stability Class D = 5399.
- 4.
Wind speed, direction measured at 9.78 meters; mean wind speed = 4.01 mph.
- 5.
Totals and subtotals are obtained from unrounded numbers.
Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report 2.7.5-11 Revision 1 Table 2.7.5-6 Joint Frequency Distribution (Hours) of Wind Speed and Direction by Atmospheric Stability Class - Stability Class E June 1, 2011 to May 31, 2013 WIND DIRECTION WIND SPEED (MPH)
CALM 0.50 1.10 1.70 2.20 2.80 3.40 4.50 6.70 8.90 11.20 13.40 18.00
>18.00 TOTAL N
0 0
86 73 27 14 9
3 3
0 0
0 0
0 215 NNE 0
3 84 58 29 14 4
3 1
0 0
0 0
0 196 NE 0
3 79 63 30 27 16 24 7
1 1
0 0
0 251 ENE 0
2 57 60 34 39 22 17 12 1
0 0
0 0
244 E
0 2
67 55 29 23 15 7
7 0
0 0
0 0
205 ESE 0
5 54 58 18 10 9
3 2
0 0
0 0
0 159 SE 0
1 46 68 16 12 5
2 2
1 0
0 0
0 153 SSE 0
0 43 32 21 19 11 11 12 4
2 0
0 0
155 S
0 2
22 43 34 24 21 12 8
7 0
0 0
0 173 SSW 0
0 18 41 28 17 17 16 5
1 1
0 0
0 144 SW 0
1 26 44 30 35 33 16 12 5
0 0
0 0
202 WSW 0
2 39 52 44 51 54 49 39 12 3
0 0
0 345 W
0 2
54 63 65 65 47 59 50 8
1 1
1 0
416 WNW 0
3 90 118 60 48 35 54 68 29 5
2 0
0 512 NW 0
3 111 96 36 40 29 46 57 20 4
0 0
0 442 NNW 0
2 82 66 21 24 11 16 4
0 0
0 0
0 226 SUBTOTAL 0
31 958 990 522 462 338 338 289 89 17 3
1 0
4038 Notes:
- 1.
JFDs based on 17380 total hours of valid wind direction-wind speed-stability observations.
- 2.
Stability based on T between 8.44 and 59.22 meters (-0.5 < T 1.5°C/100 M).
- 3.
Total hours of valid wind direction and wind speed in Stability Class E = 4038.
- 4.
Wind speed, direction measured at 9.78 meters; mean wind speed = 2.32 mph.
- 5.
Totals and subtotals are obtained from unrounded numbers.
Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report 2.7.5-12 Revision 1 Table 2.7.5-7 Joint Frequency Distribution (Hours) of Wind Speed and Direction by Atmospheric Stability Class - Stability Class F June 1, 2011 to May 31, 2013 WIND DIRECTION WIND SPEED (MPH)
CALM 0.50 1.10 1.70 2.20 2.80 3.40 4.50 6.70 8.90 11.20 13.40 18.00
>18.00 TOTAL N
0 14 90 12 1
1 1
0 0
0 0
0 0
0 119 NNE 0
14 83 23 2
3 2
1 0
0 0
0 0
0 128 NE 0
10 97 24 2
2 0
0 0
0 0
0 0
0 135 ENE 0
17 138 29 14 5
2 0
1 0
0 0
0 0
206 E
0 14 187 74 15 2
2 0
1 0
0 0
0 0
295 ESE 0
15 185 87 22 2
4 0
0 0
0 0
0 0
315 SE 0
14 153 76 15 3
1 1
0 0
0 0
0 0
263 SSE 0
5 79 32 8
4 1
1 0
0 0
0 0
0 130 S
0 11 49 29 6
5 3
2 1
0 0
0 0
0 106 SSW 0
7 32 23 11 0
2 0
2 0
0 0
0 0
77 SW 0
2 38 26 12 4
2 3
0 0
0 0
0 0
87 WSW 0
5 42 24 10 3
8 3
1 0
0 0
0 0
96 W
0 1
91 39 15 17 4
5 3
0 0
0 0
0 175 WNW 0
10 131 101 33 9
4 6
4 2
0 0
0 0
300 NW 0
16 156 59 15 13 3
2 1
0 0
0 0
0 265 NNW 0
14 99 25 3
2 0
0 0
0 0
0 0
0 143 SUBTOTAL 0
169 1650 683 184 75 39 24 14 2
0 0
0 0
2840 Notes:
- 1.
JFDs based on 17380 total hours of valid wind direction-wind speed-stability observations.
- 2.
Stability based on T between 8.44 and 59.22 meters (1.5 < T 4.0°C/100 M).
- 3.
Total hours of valid wind direction and wind speed in Stability Class F = 2840.
- 4.
Wind speed, direction measured at 9.78 meters; mean wind speed = 1.16 mph.
- 5.
Totals and subtotals are obtained from unrounded numbers.
Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report 2.7.5-13 Revision 1 Table 2.7.5-8 Joint Frequency Distribution (Hours) of Wind Speed and Direction by Atmospheric Stability Class - Stability Class G June 1, 2011 to May 31, 2013 WIND DIRECTION WIND SPEED (MPH)
CALM 0.50 1.10 1.70 2.20 2.80 3.40 4.50 6.70 8.90 11.20 13.40 18.00
>18.00 TOTAL N
0 10 34 3
2 0
0 0
0 0
0 0
0 0
49 NNE 0
5 27 1
0 0
0 1
0 0
0 0
0 0
34 NE 0
7 31 5
2 1
1 0
0 0
0 0
0 0
47 ENE 0
10 103 15 5
2 0
1 0
0 0
0 0
0 136 E
0 27 226 53 13 0
0 0
1 0
0 0
0 0
320 ESE 0
32 372 164 14 0
0 1
0 0
0 0
0 0
583 SE 0
21 334 139 7
1 2
1 0
0 0
0 0
0 505 SSE 0
17 209 41 4
1 0
0 0
0 0
0 0
0 272 S
0 15 101 21 5
0 0
0 0
0 0
0 0
0 142 SSW 0
5 73 19 5
1 0
1 0
1 0
0 0
0 105 SW 0
9 46 13 2
1 0
1 0
0 0
0 0
0 72 WSW 0
7 94 21 5
0 1
0 0
0 0
0 0
0 128 W
0 8
104 56 2
4 2
1 1
0 0
0 0
0 178 WNW 0
15 120 65 16 5
2 2
0 0
0 0
0 0
225 NW 0
9 73 19 1
1 0
0 0
0 0
0 0
0 103 NNW 0
12 40 6
0 0
0 0
0 0
0 0
0 0
58 Subtotal 0
209 1987 641 83 17 8
9 2
1 0
0 0
0 2957 Notes:
- 1.
JFDs based on 17380 total hours of valid wind direction-wind speed-stability observations.
- 2.
Stability based on T between 8.44 and 59.22 meters (T > 4.0°C/100 M).
- 3.
Total hours of valid wind direction and wind speed in Stability Class G = 2957.
- 4.
Wind speed, direction measured at 9.78 meters; mean wind speed = 1.00 mph.
- 5.
Totals and subtotals are obtained from unrounded numbers.
Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report 2.7.5-14 Revision 1 Table 2.7.5-9 Percent Occurrence for Each Wind Direction June 1, 2011 to May 31, 2013 Direction Percent N
3.936 NNE 4.217 NE 6.237 ENE 6.214 E
6.076 ESE 6.830 SE 5.967 SSE 3.993 S
4.488 SSW 3.493 SW 5.541 WSW 10.017 W
8.941 WNW 10.334 NW 9.482 NNW 4.235
Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report 2.7.5-15 Revision 1 Table 2.7.5-10 Percent in Each Stability Class June 1, 2011 to May 31, 2013 2011 to 2013 Data Class A Class B Class C Class D Class E Class F Class G Hours 2.831 3.510 6.007 31.064 23.234 16.341 17.014 Note: Stability class is based on T between 10 and 60 meters; wind speed and direction measured at 10 meters.
Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report 2.7.5-16 Revision 1 Table 2.7.5-11 Distances for the EAB and LPZ at the 16 Wind Direction Sectors Wind Direction Sector Distance from ERB to Analytical EAB LPZ Distance (feet)
(meters)
(miles)
(meters)
S 1100 335 1
1609 SSW 1100 335 1
1609 SW 1100 335 1
1609 WSW 1100 335 1
1609 W
1100 335 1
1609 WNW 1100 335 1
1609 NW 1100 335 1
1609 NNW 1100 335 1
1609 N
1100 335 1
1609 NNE 1100 335 1
1609 NE 1100 335 1
1609 ENE 1100 335 1
1609 E
1100 335 1
1609 ESE 1100 335 1
1609 SE 1100 335 1
1609 SSE 1100 335 1
1609 Notes:
- 1. The Effluent Release Boundary (ERB) includes the nuclear island, which consists of the reactor service building and all associated buildings.
- 2. The LPZ was determined as an area with a 1-mi (1609 m) radius from the CRN Site center point.
Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report 2.7.5-17 Revision 1 Table 2.7.5-12 PAVAN Modeling Inputs PAVAN Model Input Variable Value Number of Wind Speed Categories (NVEL) 13 Type of Release Ground Building Min. Cross Sectional Area (A) 0.0 m2 Containment Building Height (D) 0.0 m Release Height (HS) 10.0 m Wind Sensor Height (TOWERH) 9.78 m Conversion Correction Factor (UCOR) 150 Lower-T Sensor Height 8.44 m Upper-T Sensor Height 59.22 m Distance from Effluent Release Boundary to Analytical EAB 335 m Distance to LPZ 1609 m Note: According to NUREG/CR-2858, for a groundlevel release, a release point height (HS) of 10 m is to be used.
Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report 2.7.5-18 Revision 1 Table 2.7.5-13 CRN Site SMR 50 Percent Probability Level X/Q Values 50% Probability Level X/Q Values (sec/m3) at the EAB and LPZ Location 0-2 Hours 0-8 Hours 8-24 Hours 1-4 Days 4-30 Days Release Zone to EAB 5.58E-04 NA NA NA NA LPZ NA 4.27E-05 3.80E-05 2.94E-05 2.04E-05 Notes:
- 1.
A circular, analytical EAB was defined at a fixed distance from the effluent release boundary. The distance used from the effluent release boundary to the analytical EAB was 1100 ft (335 m).
- 2.
The LPZ was determined as an area with a 1-mi (1609-m) radius, centered on the site.
NA = Not Applicable
2.7.5-19 Revision 1 Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report Figure 2.7.5-1.
Effluent Release Boundary with Analytical EAB
2.7.5-20 Revision 1 Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report Figure 2.7.5-2.
Effluent Release Boundaries (ERBs), Analytical EAB, and Site EAB
2.7.5-21 Revision 1 Clinch River Nuclear Site Early Site Permit Application Part 3, Environmental Report Figure 2.7.5-3.
Site Center Point and Distance to the LPZ Clinch River arm of the Watts Bar Reservoir
§¨ 40 U
V 58 q
0 0.25 0.5 0.75 1
Miles Legend All-Units Center Point LPZ (1 mile from center point)
CRN Site Interstate Highway Major Road Source: Aerial, ESRI World Imagery