ML110600878

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Official Exhibit - ENT000011-00-BD01 - URS-TR-10-0003, Rev. 1, ENT-Exposure Index Calculation - Exposure Index Analysis Using MACCS2 and Calmet: Sensitivity Study Supporting the Pilgrim Station SAMA Analysis.
ML110600878
Person / Time
Site: Pilgrim
Issue date: 01/31/2011
From:
URS Corp
To:
Atomic Safety and Licensing Board Panel
SECY RAS
Shared Package
ML110030986 List:
References
50-293-LR, ASLBP 06-848-02-LR, ENT000011, RAS 19383 URS-TR-10-0003, Rev. 1
Download: ML110600878 (15)


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Nuclear Regulatory Commission Exhibit # - ENT000011-00-BD01 Docket # - 05000293 Identified: 02/22/2011 Admitted: 02/22/2011 Withdrawn:

Rejected: Stricken:

Exhibit No. ENT000011 Pilgrim LR Proceeding 50-293-LR, 06-848-02-LR URS-TR-10-0003 Revision 1 ENT - Exposure Index Calcuation Exposure Index Analysis Using MACCS2 and CALMET:

Sensitivity Study Supporting the Pilgrim Station SAMA Analysis Revision 1 January 2011

Exposure Index Analysis URS-TR-10-0003, Rev. 1 January 2011 Revision History Revision Date Major Change(s)

Initial December 2010 Original Issue 1 January 2011 Correct heading in third column of Table 1 and delete confidentiality markings on pages 7-13.

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Exposure Index Analysis URS-TR-10-0003, Rev. 1 January 2011 Exposure Index Analysis Using MACCS2 and CALMET:

Sensitivity Study Supporting the Pilgrim Station SAMA Analysis Introduction and Summary The exposure index is a metric used by the U.S. Nuclear Regulatory Commission in the Generic Environmental Impact Statement for License Renewal of Nuclear Plants, and is applied in the assessment of future plant operation risk impacts from atmospheric release pathways. In a License Renewal Application, Severe Accident Mitigation Alternatives (SAMA) analysis, the two metrics of interest are annual- and spatially-averaged consequences that are dependent on wind-directed radiological exposures to the population distributed in a 50-mile radius domain around the subject plant. The exposure index (EI) is calculated in this study as a surrogate for the SAMA analysis metrics to better understand the sensitivity of using localized wind trajectories throughout the 50-mile radius domain around the Pilgrim Nuclear Power Station, as compared to a single set of annual wind trajectories based on measurements for the Pilgrim site. For this analysis, the single set of wind trajectories is based on the 2001 annual wind rose for the Pilgrim Station as processed by the MACCS2 computer model, and the localized trajectory roses are calculated using the CALMET model.

Using the same population distribution for the fifty-mile spatial domain around the Pilgrim Station in each case, the total EI is calculated using the MACCS2-based wind rose, the CALMET-based 500 m trajectory rose, and the CALMET-based 100 m trajectory rose. The MACCS2-based EI is calculated to be 282,429. The total EI based on the CALMET trajectory roses for the 500-m elevation is equal to 291,589, or 3.24% larger than the MACCS2-based EI. The total EI based on the CALMET trajectory roses for the 100-m elevation is equal to 321,396, or 13.80% larger than the MACCS2-based EI (282,429).

Discussion The Exposure Index (EI) is a metric used by the U.S. Nuclear Regulatory Commission in the Generic Environmental Impact Statement for License Renewal of Nuclear Plants, and is applied in the assessment of future plant operation risk impacts from atmospheric release pathways (NUREG-1437, Vol. 1 page 5-19). As described in NUREG-1437, this pathway includes the exposure of individuals directly from the passage of the cloud of radioactive material released from an accident and from material deposited on the ground, as well as the longer-term effects from other terrestrial pathways such as through food ingestion of crops. The EI is a function of the population distribution surrounding the plant of interest weighted by the site-specific wind direction frequencies for the 16 different principal compass directions. Other factors, such as terrain, precipitation, and stability class have some effect on these risks, but their impact is secondary.

In a nuclear power plant Severe Accident Mitigation Alternatives (SAMA) analysis, the two consequence metrics of interest are the off-site population dose and the off-site economic costs.

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Exposure Index Analysis URS-TR-10-0003, Rev. 1 January 2011 Both of these two metrics are evaluated on an annual average basis, and consider population- and spatially-averaged consequences that are strongly dependent on wind-directed radiological exposures to the population distributed in a 50-mile radius spatial domain around the subject plant.

In the present SAMA analysis for the Pilgrim Station, the MACCS2 computer code (SNL, 1998a and 1998b) is applied to calculate off-site population dose and economic cost consequences in the 50-mile domain around Pilgrim. This study uses the EI based on the MACCS2 processing of Pilgrim 2001 meteorological data and compares it to an alternative basis using the CALMET model.

The EIs calculated between MACCS2 and the alternative CALMET model can thus provide an approximate comparison of likely differences in SAMA analysis impacts if an alternative model were available. In other words, if population and regional economic characteristics are held constant, the relative change in EI, from the MACCS2-based SAMA wind rose in one case to the CALMET based trajectory rose case in the other will indicate the relative change in SAMA PDR and OECR that would result from if a CALMET-based, trajectory rose basis model was available for use with MACCS2.

The present analysis uses the MACCS2 calculated EI, i.e., that obtained from using the wind rose output from the MACCS2 code when processing the 2001 data for Pilgrim and the population distribution developed for the SAMA analysis (NRC, 2007). This exposure index is compared to that obtained using the CALMET model (Hanna and Hendrick, 2010), and a set of trajectory rose data evaluated at the 100-m and 500-m elevations for different sites within the same Pilgrim 50-mile radius domain.

Methodology For the Pilgrim Plant exposure index analysis, the same methodology is followed as is described in NUREG-1437, Volume 1, where the exposure index is the product of the wind rose for sector i, interval j, and the population for the corresponding grid element in sector i, interval j.

16 5 Exposure Index = Wind rose (sector i, interval j x Population in grid element (sector i, interval j),

i=1 j=1 (Eqn. 1) where i is the directional sector index that ranges from 1 to 16 denoting principal compass directions N, NNE, NE, ENE, E, ESE, SE, SSE, S, SSW, SW, WSW, W, WNW, NW, and NNW, and j is the 10-mile interval index that ranges from 1 to 5 for 0-10 miles, 10 miles to 20 miles, 20 miles to 30 miles, 30 miles to 40 miles, and 40 miles to 50 miles intervals, respectively.

The tables in this document support the exposure index calculation shown above using a MACCS2-based method with one set of wind roses, and then using a set of CALMET-based wind roses, or trajectory roses.

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Exposure Index Analysis URS-TR-10-0003, Rev. 1 January 2011 Population The same population distribution is used in the exposure index analysis by both MACCS2-based and CALMET based methods. Development of these data is discussed in NRC (2007). Table 1 shows the population for the 50-mile radius around the Pilgrim Station. Column 3 of Table 1 shows the population for each of the 16 wind direction sectors and column 4 shows the percentage of the total population within each of the 16 different wind direction sectors. The next five columns list population data for 80 polar grid elements composed of five ten-mile intervals (0-10 miles, 10 miles to 20 miles, 20 miles to 30 miles, 30 miles to 40 miles, and 40 miles to 50 miles) and 16 radial sectors of 22.5o width center in each of the principal compass directions (N, NNE, NE, ENE, E, ESE, SE, SSE, S, SSW, SW, WSW, W, WNW, NW, and NNW). The last column gives the 20 - 50 mile population by sector. Summary statistics are given in the last row of Table 1 showing the percentage of population by 10-mile increment from 0 to 50 miles of the total population of 7,490,644.

MACCS2-Based Calculation of Exposure Index Table 2 shows the MACCS2-based wind rose and resulting exposure index calculation. The first three columns contain the same index, polar direction, and total population by sector as Table 1.

The fourth column shows the MACCS2 wind rose as processed by the code after reading in 8,760 hours0.0088 days <br />0.211 hours <br />0.00126 weeks <br />2.8918e-4 months <br /> of Pilgrim site-specific weather data including wind direction. The code bins all of these hourly data into weather types, or categories for subsequent calculation of SAMA consequences.

The MACCS2 model also processes all input data from 8,760 hourly records into a set of annual wind direction frequencies, shown in the fourth column, and is based on Pilgrim data for the 2001 calendar year. The fifth through ninth column contain the EI product of the wind rose (fourth column) for that sector and the population for the grid element, for that direction sector and that interval. For example, the fifth column lists the EI calculation for the 0 to 10-mile interval beginning with the N sector. The population of that sector and interval (Table 1) is 0 and this is multiplied by the wind rose for this sector and interval, which is 0.088. The product is 0 x 0.088 =

0.0. The process continues for each of 16 direction sectors for the 0 to 10-mile interval and the outcome listed in the fifth column. The sum for this column is 6,263 persons. The process continues for the next four intervals of 10 to 20 miles (sixth column), 20 to 30 miles (seventh column), 30 to 40 miles (eighth column), and 40 to 50 miles (ninth column). The corresponding interval sums by interval are: 22,516 (10-20 miles), 66,220 (20-30 miles), 120,502 (30-40 miles),

and 66,927 (40-50 miles). The total EI for the MACCS2-based calculation is 282,429, with percentages of the five intervals shown in the last line of Table 2.

CALMET-Based Calculation of Exposure Index Two sets of CALMET data were used to obtain two separate calculations of the EI based, i.e., one specific to the 500-m elevation and another specific to the 100-m elevation. Tables 3 and 4 show the information used in the trajectory rose input data processing and subsequent output for the EI analysis specific to the 500-m elevation. Tables 5 and 6 show the information used in the trajectory rose input data processing and subsequent output for the EI analysis specific to the 100-m elevation.

The basis calculation performed again uses Eqn. 1, with the exception of the trajectory rose term being substituted for the wind rose term for interval i, and sector j.

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Exposure Index Analysis URS-TR-10-0003, Rev. 1 January 2011

a. CALMET-based Exposure Index at 500 m The CALMET-based calculation of the exposure index uses the same population distribution (Table
1) as does the MACCS2-based EI analysis but incorporates additional, finer resolution measures of wind directions provided by the trajectory roses. Before applying the CALMET trajectory roses to the five-interval, 16-sector population grid an averaging process is used. CALMET trajectory roses are averaged for the 10-mile interval in question as follows:
  • 0 - 10 mile interval: wind trajectories at 1 mile, 2 miles, 3 miles, 4 miles, 5 miles, 6 miles, 7 miles, 8 miles, 9 miles, and 10 miles (The 0 to 10 mile range is the only one where trajectory roses are available every 1-mile increment).
  • 10 - 20 mile interval: wind trajectories at 10 miles and 20 miles
  • 20 - 30 mile interval; wind trajectories at 20 miles and 30 miles
  • 30 - 40 mile interval; wind trajectories at 30 miles and 40 miles; and
  • 40 - 50 mile interval; wind trajectories at 40 miles and 50 miles.

The first set of CALMET trajectory rose data are for the 500-m elevation and are taken from Appendix E of Hanna and Hendrick (2010). The data for 1 mile, 2 miles, 3 miles, 4 miles, 5 miles, 6 miles, 7 miles, 8 miles, 9 miles, and 10 miles are listed by direction in Table 3. The 0 to 10 mile interval average by direction is shown in the row with the label, 0-10 ave.. For example, the ten entries under the North direction are summed and divided by 10 to yield the 0 - 10 mile interval average of 0.1156. Other direction averages for this interval follow from NNE through NNW.

The 10 - 20 mile interval averages are then computed by averaging the trajectory roses at 10 miles and 20 miles. For example, for the North direction, the 10-mile and 20-mile trajectory roses are 0.1173 and 0.1179, respectively are averaged to obtain the value of 0.1176. Other values for this same interval are calculated in the same manner for each direction and the results are listed in the row 10-20 ave.. The same process is repeated for the 20- and 30-mile, the 30- and 40-mile, and 40- and 50-mile trajectory roses to obtain trajectory rose interval averages for the 20 - 30 mile, 30 -

40 mile, and 40 - 50 miles intervals, that are listed in rows with the labels of 20-30 ave., 30-40 ave. and 40-50 ave., respectively.

The five rows of direction-specific, ten-mile interval average trajectory rose data (0-10 ave., 10-20 ave., 20-30 ave., 30-40 ave. and 40-50 ave.) are carried forward into the following table (Table 4) as the fourth column (CALMET average of 1-, 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9-, and 10-mile trajectory roses), sixth column (CALMET average of 10-mile and 20-mile trajectory rose), eighth column (CALMET average of 20-mile and 30-mile trajectory rose), tenth column (CALMET average of 30-mile and 40-mile trajectory rose), and twelfth column (CALMET average of 40-mile and 50-mile trajectory rose) for calculation of the exposure index based on the 500-m elevation CALMET trajectory rose data. The same Equation 1 product of trajectory rose (for that sector and interval) and population from Table 1 (for the same sector and interval) was taken for the CALMET case as was performed for the MACCS2 wind rose by ten-mile interval for the following intervals:

1.) 0 to 10 miles Population Exposure Index (fifth column), 10 miles to 20 miles Population Exposure Index (seventh column), 20 miles to 30 miles Population Exposure Index (ninth column),

30 miles to 40 miles Population Exposure Index, and thirteenth column (40 miles to 50 miles Population Exposure Index). For example, for the North direction in the 40- to 50-mile interval, the trajectory rose is 0.1123 and the population from Table 1 is 80,474, with the product then being 0.1123 x 80,474 = 9,033. This process is completed for all 16 directions for each ten-mile interval.

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Exposure Index Analysis URS-TR-10-0003, Rev. 1 January 2011 The final exposure indices by ten-mile interval are listed in the Total Exposure Index row in Table 4 and are:

0 - 10 miles EI: 6,433 10 - 20 miles EI: 24, 230 20 - 30 miles EI: 64,871 30 - 40 miles EI: 123,038 40 - 50 miles EI: 73,016.

The total EI based on the CALMET trajectory roses is the sum of these five interval EIs and is equal to 291,589. This is larger by the MACCS2-based EI (282,429) by 3.24%. This ratio is shown at the bottom of Table 4 as well as the (CALMET EI)/(MACCS2 EI) ratio by ten-mile intervals, and are shown in the row with the label, CALMET/MACCS2 Ratio for Interval.

b. CALMET-based Exposure Index at 100 m The second set of CALMET trajectory rose data are for the 100-m elevation and are taken from Appendix C of Hanna and Hendrick (2010). The data for 1 mile, 2 miles, 3 miles, 4 miles, 5 miles, 6 miles, 7 miles, 8 miles, 9 miles, and 10 miles are listed by direction in Table 5. The 0 to 10 mile interval average by direction is shown in the row with the label, 0-10 ave.. For example, the ten entries under the North direction are summed and divided by 10 to yield the 0 - 10 mile interval average of 0.0922. Other direction averages for this interval follow from NNE through NNW.

The 10 - 20 mile interval averages are then computed by averaging the trajectory roses at 10 miles and 20 miles. For example, for the North direction, the 10-mile and 20-mile trajectory roses are 0.0941 and 0.0869, respectively are averaged to obtain the value of 0.0905. Other values for this same interval are calculated in the same manner for each direction and the results are listed in the row 10-20 ave.. The same process is repeated for the 20- and 30-mile, the 30- and 40-mile, and 40- and 50-mile trajectory roses to obtain trajectory rose interval averages for the 20 - 30 mile, 30 -

40 mile, and 40 - 50 miles intervals, that are listed in rows with the labels of 20-30 ave., 30-40 ave. and 40-50 ave., respectively.

The five rows of direction-specific, ten-mile interval average trajectory rose data (0-10 ave., 10-20 ave., 20-30 ave., 30-40 ave. and 40-50 ave.) are carried forward into the following table (Table 6) as the fourth column (CALMET average of 1-, 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9-, and 10-mile trajectory roses), sixth column (CALMET average of 10-mile and 20-mile trajectory rose), eighth column (CALMET average of 20-mile and 30-mile trajectory rose), tenth column (CALMET average of 30-mile and 40-mile trajectory rose), and twelfth column (CALMET average of 40-mile and 50-mile trajectory rose) for calculation of the exposure index based on the 500-m elevation CALMET trajectory rose data. The same Equation 1 product of trajectory rose (for that sector and interval) and population from Table 1 (for the same sector and interval) was calculated for the CALMET 100-m elevation case as was performed for the CALMET 500-m trajectory rose by ten-mile interval for the following intervals: 1.) 0 to 10 miles Population Exposure Index (fifth column),

10 miles to 20 miles Population Exposure Index (seventh column), 20 miles to 30 miles Population Exposure Index (ninth column), 30 miles to 40 miles Population Exposure Index, and thirteenth column (40 miles to 50 miles Population Exposure Index). For example, for the North direction in 5

Exposure Index Analysis URS-TR-10-0003, Rev. 1 January 2011 the 40- to 50-mile interval, the trajectory rose is 0.0907 and the population from Table 1 is 80,474, with the product then being 0.0907 x 80,474 = 7,299. This process is completed for all 16 directions for each ten-mile interval. The final exposure indices by ten-mile interval are listed in the Total Exposure Index row in Table 6 and are:

0 - 10 miles EI: 6,698 10 - 20 miles EI: 25,567 20 - 30 miles EI: 69,530 30 - 40 miles EI: 139,719 40 - 50 miles EI: 79,883.

The total EI based on the CALMET trajectory roses is the sum of these five interval EIs and is equal to 321,396. This is larger by the MACCS2-based EI (282,429) by 13.80%. This ratio is shown at the bottom of Table 6 as well as the (CALMET EI)/(MACCS2 EI) ratio by ten-mile intervals, and are shown in the row with the label, CALMET/MACCS2 Ratio for Interval.

Results Using the same population distribution for the fifty-mile spatial domain around the Pilgrim Station in each case, the total EI is calculated using the MACCS2-based wind rose, the CALMET-based 500 m trajectory roses, and the CALMET-based 100 m trajectory roses. The MACCS2-based EI is calculated to be 282,429. The total EI based on the CALMET trajectory roses for the 500-m elevation is equal to 291,589, or larger than the MACCS2-based EI by 3.24%. The total EI based on the CALMET trajectory roses for the 100-m elevation is equal to 321,396, or larger than the MACCS2-based EI (282,429) by 13.80%.

While neither MACCS2 to CALMET difference is large, the 500-m elevation results provided by CALMET are judged to be a better comparison over those calculated for the 100-m elevation, also with CALMET. This is because most atmospheric plumes released from the Pilgrim station will mix vertically as they move downwind and generally will extend to the full mixing layer height after twenty miles of travel downwind where most of the population is found in the 50-mile domain around the Pilgrim site. Thus, the CALMET 500 m result is more appropriate as a mid-plume height basis than 100-m basis elevation for the trajectory roses.

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Exposure Index Analysis URS-TR-10-0003, Rev. 1 January 2011 Table 1. Population Distribution Used in the Pilgrim SAMA Analysis Sector Total Population as 0 to 10 mile 10 miles to 20 miles to 30 miles to 40 miles to 20 to 50 mile Index Direction Population Percentage of Population 20 mile 30 miles 40 miles 50 miles Population by Sector Total 1N 80,474 1.07% 0 0 0 0 80,474 80,474 2 NNE 3 0.00% 3 0 0 0 0 0 3 NE 3 0.00% 3 0 0 0 0 0 4 ENE 33,124 0.44% 3 0 33,121 0 0 33,121 5E 56,311 0.75% 5 0 33,121 23,185 0 56,306 6 ESE 142,445 1.90% 23 0 49,682 92,740 0 142,422 7 SE 149,996 2.00% 950 9,936 115,925 23,185 0 139,110 8 SSE 165,647 2.21% 13,289 69,555 82,803 0 0 82,803 9S 383,324 5.12% 23,695 99,364 132,485 84,383 43,397 260,265 10 SSW 142,037 1.90% 23,695 49,762 23,696 23,185 21,699 68,580 11 SW 836,194 11.16% 23,695 71,088 277,374 349,491 114,546 741,411 12 WSW 904,685 12.08% 23,695 71,088 277,374 349,491 183,037 809,902 13 W 1,046,851 13.98% 23,695 71,088 277,374 388,324 286,370 952,068 14 WNW 899,663 12.01% 16,494 71,088 118,481 303,450 390,150 812,081 15 NW 2,212,205 29.53% 11,269 71,088 195,075 1,529,212 405,561 2,129,848 16 NNW 437,682 5.84% 5,599 35,544 43,350 31,295 321,894 396,539 Total Population 7,490,644 100.00% 166,113 619,601 1,659,861 3,197,941 1,847,128 6,704,930 Percent of Total Population 2.22% 8.27% 22.16% 42.69% 24.66% 89.51%

0 - 50 mile 7,490,644 population 100.00%

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Exposure Index Analysis URS-TR-10-0003, Rev. 1 January 2011 Table 2. MACCS2-Based Wind Rose and Exposure Index 10 miles to 20 20 miles to 30 30 miles to 40 40 miles to 50 0 to 10 miles Total miles miles miles miles MACCS2 Population Index Direction Population by Population Population Population Population Wind Rose Exposure Sector Exposure Exposure Exposure Exposure Index Index Index Index Index 1N 80,474 0.088 0 0 0 0 7,082 2 NNE 3 0.161 0 0 0 0 0 3 NE 3 0.120 0 0 0 0 0 4 ENE 33,124 0.101 0 0 3,345 0 0 5E 56,311 0.093 0 0 3,080 2,156 0 6 ESE 142,445 0.065 1 0 3,229 6,028 0 7 SE 149,996 0.045 43 447 5,217 1,043 0 8 SSE 165,647 0.031 412 2,156 2,567 0 0 9S 383,324 0.037 877 3,676 4,902 3,122 1,606 10 SSW 142,037 0.052 1,232 2,588 1,232 1,206 1,128 11 SW 836,194 0.038 900 2,701 10,540 13,281 4,353 12 WSW 904,685 0.036 853 2,559 9,985 12,582 6,589 13 W 1,046,851 0.036 853 2,559 9,985 13,980 10,309 14 WNW 899,663 0.032 528 2,275 3,791 9,710 12,485 15 NW 2,212,205 0.037 417 2,630 7,218 56,581 15,006 16 NNW 437,682 0.026 146 924 1,127 814 8,369 Total Population 7,490,644 Total Exposure Index 282,429 0.998 6,263 22,516 66,220 120,502 66,927 Percentage of Total Exposure Index 2.22% 7.97% 23.45% 42.67% 23.70%

100.00%

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Exposure Index Analysis URS-TR-10-0003, Rev. 1 January 2011 Table 3. CALMET Trajectory Rose by Direction and Distance (Based on 500-m elevation)

Distance or Ave. Trajectory Rose at Distance N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW Total 1 mile 0.1143 0.1278 0.0898 0.0939 0.0929 0.0730 0.0586 0.0500 0.0524 0.0506 0.0377 0.0308 0.0204 0.0325 0.0341 0.0411 0.9999 2 miles 0.1148 0.1279 0.0893 0.0939 0.0924 0.0730 0.0585 0.0499 0.0526 0.0506 0.0377 0.0311 0.0202 0.0327 0.0345 0.0410 1.0001 3 miles 0.1146 0.1283 0.0891 0.0940 0.0922 0.0725 0.0586 0.0498 0.0525 0.0504 0.0381 0.0307 0.0206 0.0327 0.0346 0.0415 1.0002 4 miles 0.1147 0.1287 0.0890 0.0937 0.0923 0.0724 0.0581 0.0496 0.0529 0.0501 0.0381 0.0307 0.0211 0.0327 0.0341 0.0418 1.0000 5 miles 0.1152 0.1288 0.0893 0.0935 0.0919 0.0725 0.0574 0.0495 0.0530 0.0503 0.0378 0.0304 0.0212 0.0327 0.0343 0.0421 0.9999 6 miles 0.1159 0.1293 0.0892 0.0939 0.0917 0.0722 0.0566 0.0497 0.0536 0.0497 0.0379 0.0302 0.0210 0.0328 0.0351 0.0413 1.0001 7 miles 0.1161 0.1291 0.0900 0.0934 0.0915 0.0721 0.0562 0.0499 0.0536 0.0491 0.0380 0.0302 0.0212 0.0329 0.0352 0.0416 1.0001 8 miles 0.1167 0.1293 0.0897 0.0932 0.0911 0.0720 0.0561 0.0498 0.0533 0.0496 0.0385 0.0295 0.0209 0.0329 0.0357 0.0418 1.0001 9 miles 0.1165 0.1297 0.0898 0.0929 0.0918 0.0718 0.0562 0.0491 0.0531 0.0491 0.0381 0.0295 0.0214 0.0328 0.0360 0.0423 1.0001 10 miles 0.1173 0.1301 0.0892 0.0926 0.0919 0.0718 0.0569 0.0485 0.0528 0.0484 0.0379 0.0297 0.0212 0.0333 0.0361 0.0421 0.9998 0-10 ave. 0.1156 0.1289 0.0894 0.0935 0.0920 0.0723 0.0573 0.0496 0.0530 0.0498 0.0380 0.0303 0.0209 0.0328 0.0350 0.0417 10 miles 0.1173 0.1301 0.0892 0.0926 0.0919 0.0718 0.0569 0.0485 0.0528 0.0484 0.0379 0.0297 0.0212 0.0333 0.0361 0.0421 0.9998 20 miles 0.1179 0.1337 0.0891 0.0921 0.0919 0.0694 0.0557 0.0484 0.0499 0.0481 0.0321 0.0288 0.0219 0.0333 0.0418 0.0458 0.9999 10-20 ave. 0.1176 0.1319 0.0892 0.0924 0.0919 0.0706 0.0563 0.0485 0.0514 0.0483 0.0350 0.0293 0.0216 0.0333 0.0390 0.0440 20 miles 0.1179 0.1337 0.0891 0.0921 0.0919 0.0694 0.0557 0.0484 0.0499 0.0481 0.0321 0.0288 0.0219 0.0333 0.0418 0.0458 0.9999 30 miles 0.1167 0.1341 0.0929 0.0908 0.0883 0.0666 0.0585 0.0489 0.0507 0.0466 0.0319 0.0266 0.0225 0.0338 0.0436 0.0476 1.0001 20-30 ave. 0.1173 0.1339 0.0910 0.0915 0.0901 0.0680 0.0571 0.0487 0.0503 0.0474 0.0320 0.0277 0.0222 0.0336 0.0427 0.0467 30 miles 0.1167 0.1341 0.0929 0.0908 0.0883 0.0666 0.0585 0.0489 0.0507 0.0466 0.0319 0.0266 0.0225 0.0338 0.0436 0.0476 1.0001 40 miles 0.1146 0.1307 0.0932 0.0908 0.0897 0.0668 0.0609 0.0498 0.0520 0.0465 0.0324 0.0236 0.0225 0.0353 0.0444 0.0468 1.0000 30-40 ave. 0.1157 0.1324 0.0931 0.0908 0.0890 0.0667 0.0597 0.0494 0.0514 0.0466 0.0322 0.0251 0.0225 0.0346 0.0440 0.0472 40 miles 0.1146 0.1307 0.0932 0.0908 0.0897 0.0668 0.0609 0.0498 0.0520 0.0465 0.0324 0.0236 0.0225 0.0353 0.0444 0.0468 1.0000 50 miles 0.1099 0.1369 0.0944 0.0903 0.0889 0.0666 0.0619 0.0508 0.0514 0.0481 0.0322 0.0226 0.0216 0.0357 0.0440 0.0445 0.9998 40-50 ave. 0.1123 0.1338 0.0938 0.0906 0.0893 0.0667 0.0614 0.0503 0.0517 0.0473 0.0323 0.0231 0.0221 0.0355 0.0442 0.0457 9

Exposure Index Analysis URS-TR-10-0003, Rev. 1 January 2011 Table 4. CALMET -Based Exposure Index (Based on 500-m elevation data)

CALMET CALMET 10 miles to CALMET 20 miles to CALMET 30 miles to CALMET 40 miles to Total 0 to 10 miles average of 1-, 2-, average of 10- 20 miles average of 20- 30 miles average of 30- 40 miles average of 40- 50 miles Population Index Direction Population by 3-, 4-, 5-, 6-, 7-, 8-Exposure mile and 20- Population mile and 30- Population mile and 40- Population mile and 50- Population

, 9-, and 10-mile mile trajectory Exposure mile trajectory Exposure mile trajectory Exposure mile trajectory Exposure Sector trajectory roses Index rose Index rose Index rose Index rose Index 1N 80,474 0.1156 0 0.1176 0 0.1173 0 0.1157 0 0.1123 9,033 2 NNE 3 0.1289 0 0.1319 0 0.1339 0 0.1324 0 0.1338 0 3 NE 3 0.0894 0 0.0892 0 0.0910 0 0.0931 0 0.0938 0 4 ENE 33,124 0.0935 0 0.0924 0 0.0915 3,029 0.0908 0 0.0906 0 5E 56,311 0.0920 0 0.0919 0 0.0901 2,984 0.0890 2,063 0.0893 0 6 ESE 142,445 0.0723 2 0.0706 0 0.0680 3,378 0.0667 6,186 0.0667 0 7 SE 149,996 0.0573 54 0.0563 559 0.0571 6,619 0.0597 1,384 0.0614 0 8 SSE 165,647 0.0496 659 0.0485 3,370 0.0487 4,028 0.0494 0 0.0503 0 9S 383,324 0.0530 1,255 0.0514 5,102 0.0503 6,664 0.0514 4,333 0.0517 2,244 10 SSW 142,037 0.0498 1,180 0.0483 2,401 0.0474 1,122 0.0466 1,079 0.0473 1,026 11 SW 836,194 0.0380 900 0.0350 2,488 0.0320 8,876 0.0322 11,236 0.0323 3,700 12 WSW 904,685 0.0303 717 0.0293 2,079 0.0277 7,683 0.0251 8,772 0.0231 4,228 13 W 1,046,851 0.0209 496 0.0216 1,532 0.0222 6,158 0.0225 8,737 0.0221 6,314 14 WNW 899,663 0.0328 541 0.0333 2,367 0.0336 3,975 0.0346 10,484 0.0355 13,850 15 NW 2,212,205 0.0350 394 0.0390 2,769 0.0427 8,330 0.0440 67,285 0.0442 17,926 16 NNW 437,682 0.0417 233 0.0440 1,562 0.0467 2,024 0.0472 1,477 0.0457 14,694 7,490,644 Total Exposure Index 291,589 1.0000 6,433 0.9999 24,230 1.0000 64,871 1.0001 123,038 0.9999 73,016 MACCS2 EI (Table 2) 282,429 6,263 22,516 66,220 120,502 66,927 CALMET/MACCS2 Ratio for Interval 1.0271 1.0761 0.9796 1.0210 1.0910 (CALMET EI)/

(MACCS2 EI) 1.0324 3.24%

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Exposure Index Analysis URS-TR-10-0003, Rev. 1 January 2011 Table 5. CALMET Trajectory Rose by Direction and Distance (Based on 100-m elevation)

Distance or Ave.

Trajectory Rose at Distance N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW Total 1 mile 0.0900 0.1399 0.0940 0.0753 0.0847 0.0914 0.0570 0.0512 0.0493 0.0534 0.0373 0.0327 0.0290 0.0305 0.0453 0.0389 0.9999 2 miles 0.0906 0.1398 0.0941 0.0751 0.0847 0.0911 0.0568 0.0509 0.0492 0.0538 0.0372 0.0325 0.0290 0.0305 0.0453 0.0392 0.9998 3 miles 0.0906 0.1399 0.0944 0.0751 0.0847 0.0910 0.0565 0.0512 0.0489 0.0536 0.0372 0.0324 0.0287 0.0308 0.0455 0.0397 1.0002 4 miles 0.0907 0.1404 0.0940 0.0753 0.0847 0.0911 0.0565 0.0511 0.0488 0.0534 0.0373 0.0321 0.0291 0.0304 0.0451 0.0400 1.0000 5 miles 0.0919 0.1406 0.0939 0.0754 0.0845 0.0911 0.0560 0.0504 0.0493 0.0529 0.0373 0.0317 0.0288 0.0306 0.0458 0.0397 0.9999 6 miles 0.0929 0.1409 0.0942 0.0751 0.0847 0.0911 0.0557 0.0504 0.0481 0.0532 0.0372 0.0312 0.0288 0.0313 0.0457 0.0394 0.9999 7 miles 0.0935 0.1409 0.0944 0.0750 0.0846 0.0908 0.0556 0.0504 0.0477 0.0528 0.0379 0.0305 0.0291 0.0312 0.0463 0.0392 0.9999 8 miles 0.0940 0.1406 0.0949 0.0750 0.0842 0.0910 0.0555 0.0500 0.0474 0.0521 0.0376 0.0306 0.0296 0.0317 0.0464 0.0394 1.0000 9 miles 0.0940 0.1407 0.0948 0.0749 0.0843 0.0907 0.0555 0.0497 0.0475 0.0517 0.0372 0.0305 0.0296 0.0321 0.0461 0.0407 1.0000 10 miles 0.0941 0.1405 0.0944 0.0758 0.0841 0.0898 0.0556 0.0496 0.0479 0.0504 0.0369 0.0310 0.0296 0.0319 0.0468 0.0418 1.0002 0-10 ave. 0.0922 0.1404 0.0943 0.0752 0.0845 0.0909 0.0561 0.0505 0.0484 0.0527 0.0373 0.0315 0.0291 0.0311 0.0458 0.0398 10 miles 0.0941 0.1405 0.0944 0.0758 0.0841 0.0898 0.0556 0.0496 0.0479 0.0504 0.0369 0.031 0.0296 0.0319 0.0468 0.0418 1.0002 20 miles 0.0869 0.1357 0.0949 0.0794 0.0838 0.0842 0.0541 0.0507 0.0479 0.0522 0.0323 0.0337 0.0267 0.0311 0.0519 0.0546 1.0001 10-20 ave. 0.0905 0.1381 0.0947 0.0776 0.0840 0.0870 0.0549 0.0502 0.0479 0.0513 0.0346 0.0324 0.0282 0.0315 0.0494 0.0482 20 miles 0.0869 0.1357 0.0949 0.0794 0.0838 0.0842 0.0541 0.0507 0.0479 0.0522 0.0323 0.0337 0.0267 0.0311 0.0519 0.0546 1.0001 30 miles 0.0850 0.1307 0.0966 0.0790 0.0834 0.0785 0.0533 0.0563 0.0484 0.0525 0.0336 0.0282 0.0272 0.0340 0.0536 0.0596 0.9999 20-30 ave. 0.0860 0.1332 0.0958 0.0792 0.0836 0.0814 0.0537 0.0535 0.0482 0.0524 0.0330 0.0310 0.0270 0.0326 0.0528 0.0571 30 miles 0.0850 0.1307 0.0966 0.0790 0.0834 0.0785 0.0533 0.0563 0.0484 0.0525 0.0336 0.0282 0.0272 0.0340 0.0536 0.0596 0.9999 40 miles 0.0893 0.1287 0.096 0.0815 0.0838 0.0731 0.0548 0.0598 0.0467 0.0529 0.0353 0.024 0.0259 0.0377 0.0511 0.0592 0.9998 30-40 ave. 0.0872 0.1297 0.0963 0.0803 0.0836 0.0758 0.0541 0.0581 0.0476 0.0527 0.0345 0.0261 0.0266 0.0359 0.0524 0.0594 40 miles 0.0893 0.1287 0.096 0.0815 0.0838 0.0731 0.0548 0.0598 0.0467 0.0529 0.0353 0.024 0.0259 0.0377 0.0511 0.0592 0.9998 50 miles 0.0921 0.1279 0.0991 0.0822 0.0846 0.0707 0.0573 0.0582 0.0481 0.053 0.0338 0.0255 0.0233 0.0372 0.0519 0.0548 0.9997 40-50 ave. 0.0907 0.1283 0.09755 0.08185 0.0842 0.0719 0.05605 0.059 0.0474 0.05295 0.03455 0.02475 0.0246 0.03745 0.0515 0.0570 11

Exposure Index Analysis URS-TR-10-0003, Rev. 1 January 2011 Table 6. CALMET -Based Exposure Index (Based on 100-m elevation data)

CALMET CALMET CALMET CALMET average of 1-, 0 to 10 mile 10 miles to 20 miles to CALMET 30 miles to average of average of average of 40 miles to 50 Total 2-, 3-, 4-, 5-, 6- 20 mile 30 mile average of 30- 40 miles Population 10-mile and 20-mile and 40-mile and miles Index Direction Population by , 7-, 8-, 9-, Population Population mile and 40- Population Population Exposure 20-mile 30-mile 50-mile Sector and 10-mile Exposure Exposure mile trajectory Exposure Exposure Index trajectory Index trajectory trajectory trajectory Index Index rose Index rose rose rose rose 1N 80,474 0.0922 0 0.0905 0 0.0860 0 0.0872 0 0.0907 7,299 2 NNE 3 0.1404 0 0.1381 0 0.1332 0 0.1297 0 0.1283 0 3 NE 3 0.0943 0 0.0947 0 0.0958 0 0.0963 0 0.0976 0 4 ENE 33,124 0.0752 0 0.0776 0 0.0792 2,623 0.0803 0 0.0819 0 5E 56,311 0.0845 0 0.0840 0 0.0836 2,769 0.0836 1,938 0.0842 0 6 ESE 142,445 0.0909 2 0.0870 0 0.0814 4,042 0.0758 7,030 0.0719 0 7 SE 149,996 0.0561 53 0.0549 545 0.0537 6,225 0.0541 1,253 0.0561 0 8 SSE 165,647 0.0505 671 0.0502 3,488 0.0535 4,430 0.0581 0 0.0590 0 9S 383,324 0.0484 1,147 0.0479 4,760 0.0482 6,379 0.0476 4,012 0.0474 2,057 10 SSW 142,037 0.0527 1,249 0.0513 2,553 0.0524 1,240 0.0527 1,222 0.0530 1,149 11 SW 836,194 0.0373 884 0.0346 2,460 0.0330 9,139 0.0345 12,040 0.0346 3,958 12 WSW 904,685 0.0315 747 0.0324 2,300 0.0310 8,585 0.0261 9,122 0.0248 4,530 13 W 1,046,851 0.0291 690 0.0282 2,001 0.0270 7,475 0.0266 10,310 0.0246 7,045 14 WNW 899,663 0.0311 513 0.0315 2,239 0.0326 3,857 0.0359 10,879 0.0375 14,611 15 NW 2,212,205 0.0458 516 0.0494 3,508 0.0528 10,290 0.0524 80,054 0.0515 20,886 16 NNW 437,682 0.0398 223 0.0482 1,713 0.0571 2,475 0.0594 1,859 0.0570 18,348 7,490,644 Total Exposure Index 321,396 1.0000 6,698 1.0002 25,567 1.0000 69,530 0.9999 139,719 0.9998 79,883 MACCS2 EI (Table 2) 282,429 6,263 22,516 66,220 120,502 66,927 (CALMET EI)/(MACCS2 EI) Ratio for Interval 1.0693 1.1355 1.0500 1.1595 1.1936 (CALMET EI)/

(MACCS2 EI) 1.1380 13.80%

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Exposure Index Analysis URS-TR-10-0003, Rev. 1 January 2011 References Hanna, S.R., and Hendrick, E., Analysis of Annual Wind Roses and Precipitation within about 50 Miles of the Pilgrim Nuclear Power Station, and Use of CALMET to Calculate the Annual Distribution of Trajectories from the Pilgrim Station, Report Number 129-01, Hanna Consultants, Kennebunkport, ME, (November 2010).

NRC, 2007 Generic Environmental Impact Statement for License Renewal of Nuclear Plants:

Regarding Pilgrim Nuclear Power Station - Final Report (NUREG-1437, Supplement 29), Appendix G, U.S. Nuclear Regulatory Commission Staff Evaluation of Severe Accident Mitigation Alternatives for Pilgrim Nuclear Power Station, (2007).

NUREG-1437 U.S. Nuclear Regulatory Commission, Generic Environmental Impact Statement for License Renewal of Nuclear Plants, Volume 1, Main Report.

SNL, 1998a Code Manual for MACCS2: Volume 1, Users Guide; NUREG/CR-6613 (SAND97-0594), Sandia National Laboratories, published by the U.S. Nuclear Regulatory Commission, Washington, DC, 1998.

SNL, 1998b Code Manual for MACCS2: Volume 2, Preprocessor Codes COMIDA2, FGRDCF, IDCF2; NUREG/CR-6613 (SAND97-0594), Sandia National Laboratories, published by the U.S. Nuclear Regulatory Commission, Washington, DC, 1998.

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