ML23167B007

Proposed Emergency Plan Revision - Relocation of the Technical Support Center (TSC) Supplemental Information - LOCA Dose Calculation Summary

ML23167B007
Person / Time
Site:	Surry
Issue date:	05/31/2023
From:	James Holloway Virginia Electric & Power Co (VEPCO)
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
23-074
Download: ML23167B007 (1)

Text

..

VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 May 31, 2023 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001 VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS 1 AND 2 10 CFR 50.54(q) 10 CFR 50.90 Serial No.:

23-074 NRA/GDM:

RO Docket Nos.: 50-280 50-281 License Nos.: DPR-32 DPR-37 PROPOSED EMERGENCY PLAN REVISION - RELOCATION OF THE TECHNICAL SUPPORT CENTER (TSC)

SUPPLEMENTAL INFORMATION - LOCA DOSE CALCULATION

SUMMARY

By letter dated November 18, 2022 [Agencywide Document Access and Management System (ADAMS) Accession No. ML22322A182], Virginia Electric and Power Company (Dominion Energy Virginia) submitted a license amendment request (LAR) to revise the Surry Power Station (SPS) Units 1 and 2 Emergency Plan. The proposed change would relocate the Technical Support Center (TSC) from its current location adjacent to the Main Control Room (MGR) to the building located outside the Protected Area (PA) previously used as the site Local Emergency Operations Facility (LEOF). In support of the LAR, a dose calculation was completed to confirm the projected dose to personnel in the proposed TSC from a design basis Loss of Coolant Accident (LOCA) with a release to the environment would be less than the dose limit of five (5) rem Total Effective Dose Equivalent (TEDE).

Subsequent to the LAR submittal, the NRG requested supplemental information summarizing the inputs to the LOCA dose calculation to facilitate its review. In response to the NRC request, an SPS TSC LOCA Dose Calculation Summary Report has been prepared and is provided in Attachment 1 for the NRC's information and review. The dose analysis and X/Q input and output files supporting the LOCA dose calculation are included in the enclosed CD-ROM. Attachment 2 provides a list and descriptions of the various files included on the CD-ROM. Attachment 3 includes a figure showing the site location of the relocated TSC. This figure provides the site geometry related to calculation of the X/Q dispersion factor for the relocated TSC.

Serial No.: 23-074 Docket Nos.: 50-280/281 Page 2 of 3 Should you have any questions or require additional information, please contact Mr. Gary D. Miller at (804) 273-2771.

Respectfully, James E. Holloway Vice President - Nuclear Engineering and Fleet Support Commitments contained in this letter: None.

Attachments:

1. Relocated TSC LOCA Dose Calculation Summary Report

2. Lists and Descriptions of Files included on the Enclosed CD-ROM Supporting the Relocated TSC LOCA Dose Calculation

3. Surry X/Q Geometry for the Relocated TSC

Enclosure:

CD-ROM - LOCA Dose Analysis and X/Q Input and Output Files COMMONWEAL TH OF VIRGINIA )

)

COUNTY OF HENRICO

)

The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by James E. Holloway, who is Vice President - Nuclear Engineering and Fleet Support, of Virginia Electric and Power Company. He has affirmed before me that he is duly authorized to execute and file the foregoing document in behalf of that company, and that the statements in the document are true to the best of his knowledge and belief.

Acknowledged before me this 3\\ st day of M~'(

, 2023.

My Commission Expires:

"Ja"f\\lAQ <'f 31 1 "2.01.l./.

Kathryn HIii Barret Notary Public Commonwealth of Virginia Reg. No. 7905256 My Commission Expires January 31, 2024

~4.1J--&,.J otary Public

Serial No.: 23-074 Docket Nos.: 50-280/281 Page 3 of 3 cc:

U. S. Nuclear Regulatory Commission - Region II {w/o Enclosure)

Attn: Regional Administrator Marquis One Tower 245 Peachtree Center Avenue, NE., Suite 1200 Atlanta, Georgia 30303-1257 Mr. L. John Klos NRC Project Manager - Surry Power Station U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 09 E-3 11555 Rockville Pike Rockville, Maryland 20852-2738 Mr. G. Edward Miller (w/o Enclosure)

NRC Senior Project Manager - North Anna Power Station U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 09 E-3 11555 Rockville Pike Rockville, Maryland 20852-2738 NRG Senior Resident Inspector (w/o Enclosure)

Surry Power Station State Health Commissioner (w/o Enclosure)

Virginia Department of Health

• James Madison Building - 7th floor 109 Governor Street, Suite 730 Richmond, Virginia 23219 Serial No. 23*07 4 Docket Nos.: 50-280/281 RELOCATED TSC LOCA DOSE CALCULATION

SUMMARY

REPORT Virginia Electric and Power Company (Dominion Energy Virginia)

Surry Power Station Units 1 and 2

Serial No.23-074 Docket Nos.: 50-280/281 RELOCATED TECHNICAL SUPPORT CENTER LOCA DOSE

SUMMARY

REPORT SURRY POWER STATION UNITS 1 AND 2 TABLE OF CONTENTS Page No.

1.0 Introduction and Background........................................................................................ 2 2.0 Purpose.......................................................................................................................... 2 3.0 General Methodology.................................................................................................... 2 4.0 TSC Dose Results......................................................................................................... 3 5.0 Impact Assessment....................................................................................................... 4 6.0 References................................................................................................................... 11 LIST OF TABLES Page No.

Table 4-1: Summary of TSC Dose Results......................................................................4 Table 5-1: Summary of Changes for TSC Relocation X/Q Calculation............................ 5 Table 5-2: Summary of Changes for TSC Relocation LOCA Dose.................................. 7 Page 1 of 11

Serial No.23-074 Docket Nos.: 50-280/281 RELOCATED TECHNICAL SUPPORT CENTER LOCA DOSE

SUMMARY

REPORT SURRY POWER STATION UNITS 1 AND 2 1.0 Introduction and Background As part of the Subsequent License Renewal (SLR) efforts at Surry Power Station (SPS),

the Technical Support Center (TSC) is being relocated to the former Local Emergency Operations Facility (LEOF) Building. NUREG-0737, Item 11.8.2 (Reference [1]), requires that dose to TSC personnel during a Loss of Coolant Accident (LOCA) remains below the control room dose limit of General Design Criteria (GDC) 19, which is 5 rem Total Effective Dose Equivalent (TEDE) for licensees that have adopted the Alternative Source Term (AST). Relocation of the TSC therefore requires a reanalysis of the consequences of a LOCA with respect to personnel in the new TSC location.

2.0 Purpose This report summarizes the differences in inputs and assumptions used in the calculation analyzing the dose consequences to TSC personnel in the new location and the licensing basis AST implementation.

3.0 General Methodology The ARCON96 models docketed in Reference [7], were used as the basis for determining the atmospheric dispersion factors to the new TSC location. The previously analyzed release locations were reviewed for applicability and conservatism with respect to the new TSC location and then updated to reflect the new TSC receptor location. The results of these updated ARCON96 models were extracted for use in the RADTRAD-NAI dose models.

The basis for the LOCA dose analysis is documented in Reference [2] and was approved by the NRC in Reference [8]. The analysis of record RADTRAD-NAI models developed for containment leakage, ECCS leakage, and RWST backleakage were therefore used

• as the basis for the TSC LOCA dose analysis. Only the necessary modifications to add the TSC and simplified aerosol removal coefficients were made to the models. These modifications included adding the TSC compartment, filtered intake pathway, and a TSC exhaust pathway.

The TSC RADTRAD-NAI models produced the inhalation and immersion doses for personnel within the TSC during the event.

An additional dose location within the RADTRAD-NAI models determined the immersion dose from the radioactive cloud surrounding the building to estimate shine from the cloud.

The relevant nuclide inventories with respect to the containment (sprayed and unsprayed), TSC filter, TSC compartment, and environmental integral were extracted Page 2 of 11

Serial No.23-074 Docket Nos.: 50-280/281 from the RADTRAD-NAI leakage case outputs for use in the MicroShield, MicroSkyshine, and MCNP5 models. Two MicroShield/MicroSkyshine models determined the shine dose to TSC personnel from containment. A MCNP5 model determined the shine dose to TSC personnel from the nuclide buildup on the TSC HVAC filters.

Each of the individual leakage case doses and shine component doses were summed to produce the overall TSC personnel dose for the thirty-day event.

4.0 TSC Dose Results The results of the TSC Relocation LOCA dose and the AST implementation for TSC dose are summarized in Table 4-1.

The TSC relocation analysis considered both an automatic Safety Injection (SI) signal based isolation and a manual isolation at sixty minutes. The SI-based case aligned with the assumption of receipt of an SI signal at the TSC used in the AST implementation for TSC dose; however, the new TSC location will not be provided with an SI signal. The sixty minute manual isolation case ensured TSC personnel can withstand additional time without air filtration in the event of manual TSC HVAC isolation during a LOCA. The results of both cases are presented in Table 4-1.

The increase in TSC distance from the release points resulted in a higher total TSC dose.

The cause of the increased TSC dose is due to design differences, including less efficient filters, delayed manual isolation, and modeling differences in containment skyshine, which resulted in larger contributions from some dose components that are only partially offset by the increase in TSC distance from the release points.

Although it is common for the containment skyshine component to be a smaller dose contributor than the containment direct shine, a number of conservatisms in the relocation analysis resulted in the skyshine being greater. These skyshine conservatisms included but are not limited to lack of credit for TSC wall or roof shielding due to preset code geometries, use of fewer time edits for the containment inventory resulting in

. conservatively high prediction of skyshine from 4 to 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br />, and use of low steam density for the core inventory to minimize self-shielding.

Inclusion of the TSC roof shielding would reasonably reduce the skyshine component by approximately 90%.

Page 3 of 11

Serial No.23-074 Docket Nos.: 50-280/281 Table 4-1: Summary of TSC Dose Results TSCDose rrem TEDEl LOCA Dose Component TSC Relocation SI-based 60-min ASTTSC Isolation Isolation Containment Leakage 0.0700 0.5866 0.1350 ECCS Leakage 0.2055 0.2691 0.1110 RWST Leakage 0.0162 0.0173 0.2100 Containment Direct Shine 0.0050 0.0050 0.0470 Containment Skvshine 1.6028 1.6028 0.3810 Cloudshine1 0.0361 0.0361 0.1950 Filter Shine 0.1000 0.1000 0.1600 Containment Shine through Main Steam Line Penetrations

__ 2.

0.0050 SI Piping under Main Steam Valve House & OS Pump House 0.1940 Hvdrogen Re-combiner Vault 0.0040 Total 2.04 2.62 1.30 1 Cloudshine was reported individually for each of the three release cases. The individual values are summed here for comparison to the cloudshine/plmne calculation.

2 Sources indicated with a result of"--" were deemed negligible with respect to the new TSC location due to source/receptor geometry.

5.0 Impact Assessment The TSC relocation dose inputs were compiled from several references to produce a conservatively high TSC dose. Table 5-1 and Table 5-2 below summarize the inputs of the TSC relocation dose and compare them to the existing AST implementation. These tables may assist in determining the impact of changes to the licensing basis AST implementation.

The RADTRAD-NAI models used in the TSC relocation analysis were up-converted for use in RADTRAD-NAI Version 1.3 and benchmarked to the results of the analysis of record. This change represents a licensing basis change from Version 1.2 to Version 1.3 for the LOCA dose analysis. The process of converting and benchmarking the models required a time step sensitivity to ensure alignment with previous results, as well as proper calculation of the Exclusion Area Boundary (EAB) worst two-hour dose. The RADTRAD-NAI models of the Surry LOCA releases may be used as a starting point for subsequent analysis of other personnel locations with respect to the LOCA.

Page 4 of 11

Serial No.23-074 Docket Nos.: 50-280/281 Table 5-1: Summary of Changes for TSC Relocation X/Q Calculation 7.':TSC Relocation". : -.::*~:1f~it~s1!tiB\\or'.:.~

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Meteorological Data Period 2009 - 2013 2009-2013 Table 2.0-1, {77 Lower Wind Instrument Height (m) 10.6 10.6 Table 3.1-2. (77 Upper Wind Instrument Height (m) 46.1 46.1 Table3.l-2, {77 Wind Speed Unit of Measure Miles/hour (mph)

Miles/hour (mph)

I__J_able 3.1-2, (77 Release Type Ground Ground Table 3.1-2, [77 Building Area (m2) 1453 1453 Table 3.1-2, {77 Effluent Vertical Velocity (m/s) 0.00 0.00 Table A-2, (31 Table A-2, /31 Vent/Stack Radius (m) 0.0 0.0 TableA-2, (37 Table A-2, (37 Vent/Stack Flow (m3/s) 0.0 0.0 Table A-2, (3 7 TableA-2, (37 Wind Direction Sector \\Vidth 90° 90'° Tahle A-2 7

Table A-2, (31 Terrain Elevation Difference (m) 0.0 0.0 Table A-2, {37 Table A-2, {37 Minimum Wind Speed (m/s) 0.5 0.5 TableA-2, {37 TableA-2, {37 Surface Roughness (m/s) 0.20 0.20 Table A-2, /37 Table A-2, {37 Sector Averaging Constant 4.3 4.3 Table A-2, {31 Table A-2, {37 Hours in Averages 1, 2, 4, 8, 12, 24, 96, 1, 2, 4, 8, 12, 24, 96, 168,360,720 168,360, 720 Table A-2, {3 7 Table A-2, /37 Minimum Number of Hours 1,2,,i,s,11, 87, 1, 2, 4, 8, 1 J, 22, 87, 152,324,648 152, 324, 648 Table A-2, {37 Table A-2, {37 TSC Intake Height (m) 7.7 Varied due to use of Composite X/Qs Table 3.1-1. {7J2 Containment Source Section 3.1.2.J, [7]

Source Treatment Diffuse Diffuse Sigma-Y (m) 6.86 6.86 Sigma-Z (m) 6.68 6.68 Sources Considered Ul Containment Ul/U2 Containment U2 Containment Vent Stack #2 AB Louvers - East Section 3.1.2.1, [7]

AB Louvers - West Vent#2 Page 5 of 11

J!ip~tl Source Release Heights (m)

U 1 Containment U2 Containment AB Louvers - East AB Louvers West Vent#2 Intake-to-Source Distances (m)

Ul Containment to TSC U2 Containment to TSC AB Louvers - East to TSC AB Louvers - West to TSC Vent #2 to TSC Direction from Intake to Source (degrees)

Ul Containment U2 Containment AB Louvers - East AB Louvers - West Vent#2 True North CoJTection (degrees)

Included in directions above Aux. Building East Louvers to TSC Emergency Intake X/Q 0-2 hours 2 ****** 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 8 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 24-96 hours 96 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> Aux. Building West Louvers to TSC Emergency Intake X/Q 0-2 hours 2 - 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 8 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 24-96 hours96-720 hours 1--------

U l Containment to TSC Emergency Intake X/Q 0 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> 2-8 hours 8-24 hours 24-96hours96-720 hours U2 Containment to TSC Emergency Intake X/Q 0-2hours 2-8 hours 8-24hours 24-96hours 96-720hours Vent #2 to TSC Emergency Intake X/Q 0-2hours 2-8hours 8-24 hours 24-96hours 96-720hours Page 6 of 11 20 20 7.8 8.0 21.6 237.0 239.4 281.2 280.7 262.6 211 192 198 205 197

-+23.2586 9.33E-05 8.38E-05 3.86E-05 2.80E-05 2.22E-05 9.45E-05 8.48E-05 3.92E-05 2.85E-05 2.26E-05 1.0SE-04 9.40E-05 4.31E-05 3.18E-05 2.56E-05 1.04E-04 9.06E-05 4.09E-05 3.0lE-05 2.37E-05 l.llE-04 9.42E-05 4.37E-05 3.18E-05 2.SlE-05 Serial No.23-074 Docket Nos.: 50-280/281 Table 3.1-1, {7]1 20 8.0 21.6 Table 3.1-1., [7]2 Varied due to use of Com positc XIQs Table 3.1-1, [7J2 Varied due to use of Composite X/Qs

+23.2586 Figure 3.1-1, [7]

• Table 3.J_:4, 1.

• Not considered a credible path for the Control Room (CR) and existing TSC Not considered a credib Jc path for the CR and existing TSC 4.67E-04 3.67E-04 1.50E-04 l.13E-04 S.78E-05 Ul X/Qs are limiting of U2 releases to the CR and existing TSC 6.55E-04 4.93E-04 2.03E-04 1.44E-04 l.08E-04

Serial No.23-074 Docket Nos.: 50-280/281

-~µp{!il Assum.et$!!.

1 For TSC specific inputs, "Implementation of AST," refers to the use of AST acceptable inputs in the TSC dose analyses rather than docketed inputs with respect to the TSC dose.

2 Control Room (CR) X/Qs documented in Reference [7] were used for the existing TSC location due to their proximity and the TSC intake residing inside the Turbine Building (TB). The CR X/Qs were determined based on a composite of the values for TB openings. As such, the Ul X/Qs were determined to be bounding of the U2 releases and the Auxiliary Building (AB) louvers were not considered credible release paths for the CR and existing TSC. Intake-to-Source distances and directions for the CR X/Qs are subsequently not included in this table as they are varied based on multiple intakes in determination of the composite X/Q.

3 The Vent #2 X/Qs are the only X/Q values used to determine dose for the relocated TSC. The Vent #2 X/Qs are the largest and most conservative for the first 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> of the accident. After 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br />, the Vent #2 X/Qs are the largest X/Q values for a viable release path as the containments are subatmospheric with releases terminated by 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. X/Qs for the current TSC are shown for comparison to the values calculated for the relocated TSC.

Table 5-2: Summary of Changes for TSC Relocation LOCA Dose

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Core inventory 110 isotopes 110 isotopes Table 3-3, {27 Table 3-3, !27 Fuel Design Westinghouse 15xl5 Westinghouse 15x15 Section 1.1, (27 Section 1.1, {2 7 Fuel Type UO2 UO2 Section 3.4, (4]

Section 3.4, {47 Fuel Enrichment Range (w/o) 3.60-4.75 3.60-4.75 Table2.0-1, {77 Table 2.0-1, !77 Thermal Power (MWt) 2605 2605 lncludinf! >0.38% calorimetric uncertainty Table 1-1, {27 Table 1-1, {27 End of Cycle Core Average Bumuo (GWD/MTU) 37.69 37.69 Batch Average Bumup (GWD/MTU)

Upto 56 Up to 56 Table 2.0-1, {77 Table 2. 0-1, !77 Release from fuel Tables 2 and 4, f 5 l Tables 2 and 4, {5 7 Containment Leakage Chemical Release Form 95% aerosol 95% aerosol (Section 3.5 of Reg. Guide 1.183, [5])

4.85% elemental 4.85% elemental 0.15% organic 0.15% organic Table 1-1, !27 ECCS Leakage Chemical Release Form 97% elemental 97% elemental (Appendix A of Reg. Guide 1.183, [5])

3% organic 3% organic Table 1-1, {27 RWST Leakage Chemical Release Form 97% elemental 97% elemental (Appendix A of Reg. Guide 1.183, [ 5])

3% organic 3% organic Table 1-1, {27 Dose conversion factors FGR 11 and 12 FGR 11 and 12 Section 1.3, {27 Containment net free air volume (ft3) 1.819 million 1.819 million Table 2-1, {27 Fraction of containment volume that is sprayed(%)

Tables 1-1 and 2-1, [5]

100 seconds - 1.14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br /> 61.00%

61.00%

1.14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br /> - 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> 18.78%

18.78%

Page 7 of 11

Exchange rate between sprayed and unsprayed ( c:fm) 100 seconds - 1.14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br /> 1.14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br /> - 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> (2x Unsprayed Volume/hr, Assumption 3.3, App. A of Reg, Guide 1.183, r 51)

Natural deposition coefficient for aerosol in unsprayed region of containment (hour1)

Beginning of containment spray and mixine: between soraved and unsoraved Duration of containment spray (hours)

Organic Iodine Elemental Iodine (time to reach DF 200)

Particulate/aerosol Spray removal coefficient (hours*1) 2 Organic iodide Elemental iodine Particulate/aerosol 100 seconds - 0.194 hours0.00225 days <br />0.0539 hours <br />3.207672e-4 weeks <br />7.3817e-5 months <br /> 0.194 - 0.556 hour0.00644 days <br />0.154 hours <br />9.193122e-4 weeks <br />2.11558e-4 months <br />s2 0.556 - 1.00 hour0 days <br />0 hours <br />0 weeks <br />0 months <br />s2 1.00 - 1.14 hour1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br />s2 1.14 1.80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br /> 1.80 1.83 hours9.606481e-4 days <br />0.0231 hours <br />1.372354e-4 weeks <br />3.15815e-5 months <br /> 1.83 1.87 hours0.00101 days <br />0.0242 hours <br />1.438492e-4 weeks <br />3.31035e-5 months <br /> 1.87-2.02 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> 2.02 2.61 hours7.060185e-4 days <br />0.0169 hours <br />1.008598e-4 weeks <br />2.32105e-5 months <br /> 2.61 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> Containment leak rate (percent per day) first hour 1 - 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> Filter efficiencv Control Room Organic iodine Elemental iodine Particulate/aerosol Technical Support Center for dose determination3 Organic iodine Elemental iodine Particulate/aerosol for filter inventory (shine dose analysis)

Organic iodine Elemental iodine Particulate/aerosol Auxiliary Building Organic iodine Elemental iodine Particulate/aerosol Page 8 of 11 23,647 49,246 Not analyzed 100 seconds NIA 2.33 720 Zero 10 3.59 3.59 3.59 3.59 30.40 19.40 13.50 7.21 3.91 3.43 0.10 0.04 70%

90%

99%

95%

95%

95%

99%

99%

99%

70%

90%

99%

Serial No.23-074 Docket Nos.: 50-280/281 23,647 49,246 Table 2-1, [2]

Not analyzed Table 1-1, {27 100 seconds Table 1-2, [2]

Table 1-1, [2]

NIA 2.33 720 Table 1-1, [2]

Zero 10 3.59 3.69 4.16 4.40 30.40 19.40 13.50 7.21 3.91 3.43 Table 2-1, [2]

0.10 0.04 Table 1-1, [2]

70%

90%

99%

99%

99%

99%

99%

99%

99%

Table 1-1, [2]

70%

90%

99%

Contrnl Room Effective volume (ft3)

Filtered inflow from environment (cfm) first hour after first hour Unfiltered inleaknge (cfin)

Time delay (minutes)

To isolate To pressurize Recirculation Flow ( cfin)

Vent #2 to CR Emergency Intake X/Q (sec/m3) 0-2 hours 2-8 hours 8-24 hours 24-96 hours96-720 hours Containment to CR Emergency Intake X/Q (sec/m3) 0-2 hours 2-8 hours 8-24 hours 24-96 hours96-720 hours Technical Sunnort Center Mixine volume (ft:3)

Filtered inflow (cfm)

Operational Flow Range Before isolation (unfiltered)

After isolation Immediate Isolation Cases Unfiltered inleakage ( cfin)

Time delay to enter emergency operation/iso latioIJif!Jtration (minutes)

Recitculation flow ( cfm)

Construction Details Wall Thickness (ft)

Wall Material Roof Thickness (ft)

Roof Material Building Prc_ssure in Emergency Operation (in w.g.)

Enhyway Dctai Is Serial No.23-074 Docket Nos.: 50-280/281 223,000 223,000 Table 1-1, {27 Table 1-1, [2]

0 0

900 900 250 250 Table 1-1, {21 Table 1-1, [2]

0 0

60 60

.~-- *--*

0 0

Table 1-1, /21 Table 1-1, [2]

6.55E-04 6.55E-04 4.93E-04 4.93E-04 2.03E-04 2.03E-04 1.44£-04 1.44E-04 l.08E-04 l.08E-04 Table 1-1, [2]

4.67E-04 4.67E-04 3.67E-04 3.67E-04 1.50E-04 l.50E-04 1.13E-04 l.13E-04 8.78E-05 8.78E-05 34,900 38,100 670- 1000 +/- 10%

1100 603 Constant 11004 1000 0

0 0.5 (60 minute manual isolation also analyzed) 0 0

0 1.0 LO Concrete Concrete 1.0 1.0 Concrete Concrete 0.125 Positive Vestibule with Double Vestibule with Double Doors Doors Page 9 of 11

Breathing rates ( cubic meters/second)

Control room (all the time)

TSC (all the time)

EAB LPZ 0- 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 8-24 hours after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 1 Control Room Occupancy factors First day between 1 to 4 days after 4 days TSC Occupancy factors 0-24 hours 24 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> 96-720hours Offsite X/Qs (sec/m3)

Exclusion Area Boundary 0-720hours Low Population Zone 0- 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 8

24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 24-96 hours96-720 hours

! Filtered ECCS leakage (cc/hr) [Auxiliary Building Filters}

i 0.5 -720 hours Unfiltered ECCS leakage (cc/hr) 0.25 - 0.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> 0.5 720hours Containment sump liquid volume (fl:3)

RWST Flow rate ( cfm)

Duration (hours)

Filter Efficiency (Auxiliary Building)

Aerosol Elemental Organic Fraction of activity in ECCS liquid leakage released as airborne ECCS back-leakage into RWST during recirc (cc/hr)

RWST free air volume (fl3)

Page 10 of 11 Section 4.1.3, {5]

3.5 X 104 3.5 X 104 3.5 X 10*4 Section 4.1.3, [5]

3.5 X J0-4 1.8 X 10-4 2.3 X 10-4 Section 4.2. 6, [5 J 1.0 0.6 0.4 1.0 1.0 1.0 l.02E-03 5.66E-05 3.&4E-05 l.66E-05 4.95E-06 6,000 6,000 24,000 55,986 1000 0.5 720 99%

90%

70%

10%

18,000 50,502 Serial No.23-074 Docket Nos.: 50-280/281 Table 1-1, [2]

3.5 X 10-4 3.5 X 10-4 Table 1-1, [2]

3.5 X 10*4 Table 1-1, [2]

3.5 X 10-4 1.8 X 10-4 2.3 X 10*4 Table 1-1, /2]

1.0 0.6 0.4 1.0 0.6 0.4 Table 1-1, f2]

l.02E-03 5.66E-05 3.84E-05 l.66E-05 4.95E-06

• -----Table 2.0-1, [7} &

Section 3.2, [8]

6,000 Table 2. 0-1, [7]

Section 3.2, {8]

6,000 24,000 55,986 Table 2-1, /2I Tables 1-3, and 2-1, {4]

1000 0.5-720 Table 1-1, f4]

99%

90%

70%

10%

Section 3.5.2, [21 18,000 Table 2-1, !27 50,502 Table 2-1, 127

Sources of shine dose to TSC personnel Containment Construction Wall Concrete Thickness (ft)

Wall Steel Liner Thickness (in)

Dome Concrete Thickness (ft)

Dome Steel Liner Thickness (in)

Containment shine, Serial No.23-074 Docket Nos.: 50-280/281 Containment shine, Containment skyshine, Containment skyshine, plume/cloud, and SI piping, Hydrogen HV AC filters Recombiner Vault, plume/cloud, and HV AC filters 4.5 Not listed 0.375 Not listed 2.5 2.5 0.5 Not listed 1 For TSC specific inputs, "Implementation of AST," refers to the use of AST acceptable inputs in the TSC dose analyses rather than docketed inputs with respect to the TSC dose.

2 Reduction of the aerosol spray removal coefficient from 0.194 to 1.14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br /> accommodates a relaxation of the Containment Spray minimum design flow rate.

3 The TSC charcoal filter efficiency was reduced due to the new TSC location having 2" charcoal filters versus the existing TSC use of 4" charcoal filters. Assumed HEPA filter efficiency for particulate removal is conservative.

4* Filtration is delayed 30 seconds for damper operation in the immediate isolation cases for the relocated TSC.

6.0 References

1. NUREG-0737, "Clarification of TMI Action Plan Requirements", November 1980.

2. Letter from Virginia Electric and Power Company to the USN RC (Serial No.20-381) dated December 3, 2020, "Virginia Electric and Power Company Surry Power Station Units 1 and 2 Proposed License Amendment Request Update of the Loss of Coolant Accident Alternative Source Term Dose Analysis." [ML20338A542]

3. Regulatory Guide 1.194, Revision 0, "Atmospheric Relative Concentrations for Control Room Radiological Habitability Assessments at Nuclear Power Plants," June 2003.

4. Surry Updated Final Safety Analysis Report, Revision 54, September 2022.

5. Regulatory Guide 1.183, Revision 0, "Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors", July 2000.

6. Letter from the USNRC to Virginia Electric and Power Company dated June 12, 2019, "Surry Power Station, Unit Nos. 1 and 2 - Issuance of Amendment Nos. 295 and 295

• to Adopt TSTF-490, Revision 0, and Update Alternative Source Term Analyses (EPID L-2018-LLA-0068)." [ML19028A384]

7. Letter from Virginia Electric and Power Company to the USNRC (Serial No.18-069) dated March 2, 2018, "Virginia Electric and Power Company, Surry Power Station Units 1 and 2, Proposed License Amendment Request, Adoption of TSTF-490 and Update of the Alternative Source Term Analyses." [ML18075A021]

8. Letter from the USNRC to Virginia Electric and Power Company dated November 19, 2021, "Surry Power Station, Units 1 and 2, Issuance of Amendment Nos. 306 and 306 to Update the Loss-of-Coolant Accident Alternate Source Term Dose Analysis (EPID L-2020-LLA-0258)." [ML21253A063]

Page 11 of 11 Serial No.23-074 Docket Nos.: 50-280/281 LISTS AND DESCRIPTIONS OF FILES INCLUDED ON THE ENCLOSED CD-ROM SUPPORTING THE RELOCATED TSC LOCA DOSE CALCULATION Virginia Electric and Power Company (Dominion Energy Virginia)

Surry Power Station Units 1 and 2

Serial No.23-074 Docket Nos.: 50-280/281 LISTS AND DESCRIPTIONS OF FILES INCLUDED ON THE ENCLOSED CD-ROM SUPPORTING THE RELOCATED TSC LOCA DOSE CALCULATION CD-ROM contents:

The enclosed CD-ROM contains a zip file named Surry Computer IQ.zip. The following table describes the contents of the zip file.

Surry Computer Files File Name Description sps _ ctmt _ TSC.psf LOCA containment leakage model for TSC dose with automatic isolation at thirty seconds.

sps_eccs_TSC.psf LOCA ECCS leakage model for TSC dose with automatic isolation at thirty seconds.

sps_rwst_TSC.psf LOCA RWST leakage model for TSC dose with automatic isolation at thirty seconds.

sps_ctmt_TSC_lso/60.psf LOCA containment leakage model for TSC dose with manual isolation at 60 minutes into the accident.

sps_eccs_TSC_]so/60.psf LOCA ECCS leakage model for TSC dose with manual isolation at 60 minutes into the accident.

sps_rwst_TSC_lso/60.psf LOCA RWST leakage model for TSC dose with manual isolation at 60 minutes into the accident.

sps_ctmt_TSC_]so/90.psf LOCA containment leakage model for TSC dose with manual isolation at 90 minutes into the accident.

sps_eccs_TSC_]so/90.psf LOCA ECCS leakage model for TSC dose with manual isolation at 90 minutes into the accident.

sps_rwst_TSC_]so/90.psf LOCA RWST leakage model for TSC dose with manual isolation at 90 minutes into the accident.

sps_ctmt_TSC_99.psf LOCA containment leakage model for maximum TSC filter loading with automatic isolation at thirty seconds.

sps_eccs_TSC_99.psf LOCA ECCS leakage model for maximum TSC filter loading with automatic isolation at thirty seconds.

sps_rwst_TSC_99.psf LOCA RWST leakage model for maximum TSC filter loading with automatic isolation at thirty seconds.

surry_inventory_Reformat.nif Nuclide inventory file upconverted and refonnatted for use with RADTRAD-NAI Version 1.3.

Page 1 of 3

File Name surry-caf inp pwr _dba.rft sps _ rwst.rft SPSTSC.i c-a

• _:_***;c cont shine XX.msd filename.mxd filename.pdf cont _sky_ XX.sky cont _sky_ XX.pd/

le-leof.rsf le-leof.log le-leof.cfd lw-leof.rsf lw-leof.log lw-leof.cfd ul-leof.rsf ul-leof.log u 1-leof.cfd u2-leof.rsf u2-leof.log u2-leof.cfd Serial No. 23-07 4 Docket Nos.: 50-280/281 Description Dose conversion factor file.

Release fraction timing file for containment leakage during a LOCA.

Release fraction timing file for RWST backleakage during a LOCA.

MCNP file for determination of filter shine to TSC personnel. Model evaluates doses directly beneath the primary filter shine sources and existing floor penetrations.

MicroShield case file for determination of containment shine to TSC personnel.

Four subcases are derived from the base model for various times in hours from the start of the event indicated by the two-digit suffix (XX).

External source files for use in MicroShield.

MicroShield Output files.

Case file for determination of skyshine from containment to TSC personnel. Two subcases are derived from the base model for various times in hours from the start of the event indicated by the two-digit suffix (XX).

MicroSkyshine Output File ARCON96 run specification file for LE source ARCON96 output file for LE source ARCON96 cumulative frequency distribution file for LE source ARCON96 run specification file for L W source ARCON96 output file for L W source ARCON96 cumulative frequency distribution file for L W source ARCON96 run specification file for Ul source ARCON96 output file for Ul source ARCON96 cumulative frequency distribution file for Ul source ARCON96 run specification file for U2 source ARCON96 output file for U2 source ARCON96 cumulative frequency distribution file for U2 source Page 2 of 3

File Name v2-leof.rsf v2-leof.log v2-leof.cfd RS0913.MET Description ARCON96 run specification file for V2 source ARCON96 output file for V2 source Serial No.23-074 Docket Nos.: 50-280/281 ARCON96 cumulative frequency dish*ibution file for V2 source Surry Meteorological Data file Page 3 of 3 Serial No. 23-07 4 Docket Nos.: 50-280/281 SURRY X/Q GEOMETRY FOR THE RELOCATED TSC Virginia Electric and Power Company (Dominion Energy Virginia)

Surry Power Station Units 1 and 2

84 Unit 1 Unit 2 V2 LE LW Serial No.23-074 Docket Nos.: 50-280/281 SURRY X/Q GEOMETRY FOR THE RELOCATED TSC Unit 1 Containment Unit 2 Containment

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Enclosure Serial No. 23-07 4 Docket Nos.: 50-280/281 CD-ROM - LOCA DOSE ANALYSIS AND X/Q INPUT AND OUTPUT FILES Virginia Electric and Power Company (Dominion Energy Virginia)

Surry Power Station Units 1 and 2