Text

SCE Calculation SO1-207-1-C116, Revision 2, Modified Control Area Boundary ISFSI Dose Calculation
	ML22062B039
Person / Time
Site:	San Onofre
Issue date:	12/16/2021
From:	; Southern California Edison Co
To:	; Office of Nuclear Material Safety and Safeguards
References
	5O1-207-1-C116, Rev 2
	Download: ML22062B039 (30)
	v • d • e

ENCLOSURE 1 SCE Calculation SO1-207-1-C116, Revision 2 Modified Control Area Boundary ISFSI Dose Calculation

Southern California Edison Company CALC NO. 5O1-207-1-C116 PAG E 1 I TOTAL NO. 29 ENGINEERING CHANGE I OF PAGES NOTICE (ECN)/CALCULATION NECP Order No. CALC . REV. UNIT ECN/CCN NO.

CHANGE NOTICE (CCN)

COVER PAGE 1220-20365-6 2 1

SUMMARY

CHANGE CALCULATION

SUBJECT:

181 NO YES MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION CALCULATION CROSS-INDEX ENG INEERING SYSTEM NUMBER/ PRIMARY STATION SYSTEM Q-CLASS 181 New/Updated Index Included DES IGNATOR I D Existing Index is Complete II Site Programs/Procedure Impact? CONTROLLED PROGRAM OR PROGRAM/ DATABASE NAME(S) VERSION / RELEAS E NO.(S)

DATABASE ACCORDING TO ENG-11 ALSO , LISTED BELOW 181 NO YES , AR No.

10 CFR 50 .59/72.48 PROGRAM DATABASE NIA NIA Assignment. Not required, see below

1. BRIEF DESCRIPTION OF ECN/CCN :

This calculation extracts results from a series of TN and Holtec calculations associated with ISFSI doses to project the dose at the 100-meter perimeter and at the proposed modified Control Area Boundary (CAB) in support of an exemption request for an ISFSI CAB reduction as shown on Towill Survey 15907-127-CAB Exhibit The proposed modified CAB changes were made to reflect actual physical/identifiable site boundaries (e .g.,

seawall and OCA fence).

In addition, this calculation presents a scoping analysis to assess the total annual dose for when a Multi-Purpose Canister (MPC) transfer from a WM to a HI-STAR transportation cask begins in the future .

The term Control Area is defined in 10 CFR Part 72 . The boundary is used to demonstrate acceptable near-site ISFSI doses to comply with 10 CFR 72.104 and 72.106. The 'standard ' value is no less than 100 meters. NRC approval is required if the Control Area boundary is within 100 meters.

Historically, SONGS has used the Exclusion Area Boundary as the Control Area Boundary. Doing so reduces the calculated doses at the Control Area Boundary but includes areas far off-site . Notably it includes the adjacent transportation corridors (Old Highway 101 , 1-5, and the rail line) as well as the area across 1-5 typically referred to as 'the Mesa .'

This calculation supports the contents of the two 1o CFR 72 .212 Reports (DCS-001 and DCS-002) . Section 1O of each includes the required 10 CFR 72.104 dose results .

This calculation does not directly impact the Exclusion Area Boundary which may be modified or eliminated altogether as a separate effort. It is not based on ISFSI dose impacts projected herein.

The proposed modified CAB is in support of an exemption request for an /SFSI CAB reduction. The proposed modified CAB cannot be implemented without prior NRC approval. No 10 CFR 72.48 assignment is required.

2. OTHER AFFECTED DOCUMENTS:

18] YES 0 NO OTHER AFFECTED DOCUMENTS EXIST.

3. APPROVED BY: ESC : -

Digita lly signed by Mark Drucker Digitally signed by Jerry Mark Drucker Date 2021 .12.16 120751

-08'00' Jerry Stephenson Stephenson Date: 202 1.12.16 14:47:44 -08'00' MARK DRUC KER JERRY STEPHENSON ORIGINATOR (Print name/s ign/date) IEM or EOM (Signature/date)

Approval requires PQS T3EN64 Qualification Verified : BAS Approval requires PQS T3EN64 Qualification Verified : BAS >

Initial Initial Randall Granaas ~§;..~~~~* Sasan Etemadi g~~~~;t;11:Y,~:::~;:~~

RANDALL GRANAAS SASAN ETEMADI IRE (Print name/sign/date) Techn ical Reviewer (Signature/date)

Approval requires PQS T3EN64 Qualification Verified: BAS Initial

ECN /CCN NO. PAGE _2_ OF _29_

CALCULATION CROSS-INDEX Calculation No. _SO1-207-1-C116 _ _ _ _ _ _ _ _ _ _ _ _ _ __ __ _ _ _ _ __ Sheet _ _ 1__ of _ _ 1__

INPUTS OUTPUTS Identify output interface Cale. rev. number Does the ca le/document and responsible These interfacing calculations and/or documents output interface IEM or EOM initials provide input to the subject calculation , and if revised Results and conclusion of the subject calculation are used in ca le/document CCN , NECP, Rev.,

and date may require revision of the subject calculation . these interfacing calculations and/or documents . require change? or tracking number.

Cale/Document No. Rev. No. Cale/Document No. Rev. No. YES/NO 1814-AR171-C0058 0 2 SO23-207-16-C95 1 SO1-207-1-C166 2 SO23-207-50-C0006 1 DCS-001 11 and CCN YES 1220 - 20365 -1 DR761058 DCS-002 2 and CCN YES 1220 - 20365 -2 DR761064

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1 -207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 3 of 29 Modified Control Area Boundary ISFSI Dose Calculation

CALCULATION SHEET NECP No . 0820-75665-6 Cale No. SO1-207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 4 of 29 1.0 Introduction and Purpose This calculation demonstrates compliance with 10 CFR 72 .104 dose limits [Reference 5.1] at the 100-meter perimeter and at the proposed "post-exemption Control Area Boundary (CAB)".

The initial issuance of this calculation addressed dose at the Exclusion Area Boundary (EAB) to the West and South and 100 meters to the North and East. Figure 1.1 shows the EAB .

Figure 1.2 shows the 100-meter perimeter around the ISFSI fence and the proposed modified CAB, as evaluated in Revision 1 of this calculation , that reduced the west side of the perimeter inland to be consistent with the NIA seawall on the west side, the OCA fence line to the north and east, and to the ISFSI fence line (extended) on the south side.

Figure 1.3 shows the 100-meter perimeter around the ISFSI fence and the proposed "post-exemption CAB" in support of an exemption request for an ISFSI CAB reduction as shown on Towill Survey 15907-127-CAB Exhibit (Reference 5.8) . The proposed post-exemption CAB changes were made to reflect actual physical/identifiable site boundaries (e.g., seawall and OCA fence). With respect to the Figure 1.2 CAB (introduced in Revision 1 of this analysis) , the proposed post-exemption CAB is generally closer to the ISFSI towards the Northwest and East, the same to the West and North , and more distant from the ISFSI towards the South.

Consistent with Reference 5.5, appropriate occupancy factors (i.e. , residency times) are used in the annual dose calculation for the 100-meter boundary and the modified CAB . Since the SONGS OCA encompasses both the 100-meter boundary and the modified CAB , occupancy will be controlled . In addition, the appropriate occupancy factor selected for the west side (beach) will bound occupancy further west in the ocean . Similarly, areas south of the OCA boundary are an inhospitable environment [Reference 5.7] so there is no reason for a person to remain near the south boundary for any significant period of time. The occupancy factor selected for the south ISFSI fence is conservative for the area south of the OCA boundary. However, in the areas north of the OCA fence and east of Interstate Highway 1-5, full (unrestricted 8760 hours0.101 days 2.433 hours 0.0145 weeks 0.00333 months per year) occupancy may be possible. This calculation will also demonstrate compliance with 10 CFR 72.104 dose limits in these areas.

This calculation does not impact the primary purpose of the EAB which is an area in which SCE can control access directly or through others in the case of events warranting off-site access controls. A conforming change to the EAB may be pursued separately but is not the subject of this calculation .

The purpose of this calculation is to summarize the SONGS ISFSI total annual dose at the boundaries shown in Figure 1.3, from SONGS ISFSI storage of Spent Nuclear Fuel and Greater Than Class C (GTCC) waste.

In addition , a scoping analysis is presented to assess the total annual dose for when a Multi-Purpose Canister (MPC) transfer from a WM to a HI-STAR transportation cask begins in the future.

The post-exemption CAB more effectively reflects the potential dose adjacent to the ISFSI with a focus on eliminating the transportation corridors, eliminating unnecessary restrictions along the beach to the west of the ISFSI , and eliminating areas of Camp Pendleton east of Interstate Highway 1-5 that were formerly utilized in support of SONGS .

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1-207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 5 of 29 Figure 1.1. SONGS Exclusion Area Boundary

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' , , P AC IFIC I I OCEII M /

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CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1 -207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 6 of 29 Figure 1.2. SONGS Proposed Modified Controlled Area Boundary (as previously proposed and documented in Revision 1)

N N

r0 N

r-r-0

- 100-Meter Perimeter Modified CAB

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1 -207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 7 of 29 Figure 1.3. SONGS Proposed Post-Exemption Controlled Area Boundary

[perTowill Survey 15907-127-CAB Exhibit]

[Note: The 100-meter perimeter shown in this Figure 1.3 is the same as the 100-meter perimeter shown in Figure 1.2]

LECE~D:

------------* VOOIFlEO C* B LINE

- * - * -* - CB LI

- - - - - LIIJITS SC\CS 80U\0 AHY 8 ~SEO C"I 2015 RECOR~ Cf SU'l\'EY NO 22 J8G

- - - - - - ISFSI FE\CE LI NE

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1-207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 8 of 29 2.0 Calculation Inputs 2.1 Exclusion Area Boundary (EAB) and Controlled Area Boundary (CAB)

Figure 1.1 identifies the EAB , and Figure 1.3 presents the post-exemption CAB being considered for this calculation .

2.2 Occupancy Factors Occupancy factors (hours per year) to be used with the SONGS post-exemption CAB annual dose calculations are listed in Table 2.2.1. These occupancy factors are consistent with those used in related Radiological Environmental Monitoring Program and Off-Site Dose Calculational Manual reflected in the Annual Environmental Operating Reports made to the NRC .

Table 2.2.1 Occupancy Factors Direction with Occupancy Factor Reference/Justification respect to the ISFSI (hours/year)

North 20 Occupancy Factor Memorandum (Reference 5.7] .

(at the top of the This value is conservatively greater than the bluff) 8 hour9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months s/year specified in Reference 5.7 for the west fence of Parking Lot 1 at the top of the bluff.

East 20 Reference 5.7 (towards Interstate 5)

West 300 Reference 5.7 (on the beach)

South 20 The area south of the CAB fence is within the (towards the Units 2 SONGS Owner control area with access precluded and 3 power block) for the public. An occupancy factor of 20 hour2.314815e-4 days 0.00556 hours 3.306878e-5 weeks 7.61e-6 months s/year is used to accommodate occasional visitors. This value is conservatively greater than the 8 hour9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months s/year specified in Reference 5.7 for the Owner Controlled Area perimeter located to the south of Unit 3 and South Yard Facility.

2.3 Doses Due to Storage of Spent Nuclear Fuel and GTCC in the TN ISFSI Per DCS-001 (Reference 5.9, Section 10.1.3) seventeen (17) 24PT1 Dry Storage Canisters (DSCs) containing SONGS Unit 1 spent nuclear fuel , thirty-three (33) 24PT4 DSC containing SONGS Units 2&3 spent nuclear fuel , and one modified 24PT-1 DSC storing SONGS Unit 1 Greater Than Class (GTCC) waste are currently stored within Advanced Horizontal Storage Modules (AHSM) on the ISFSI pad .

2.3.1 Annual Doses from Spent Nuclear Fuel Storage in the TN ISFSI The TN ISFSI storage dose calculation [Reference 5.2] provides annual doses at on-site and off-site locations due to radiation shine from the spent fuel stored at the TN ISFSI. The calculation assumes all DSCs are loaded with design basis spent nuclear fuel assemblies. The existing TN

CALCULATION SHEET NECP No . 0820-75665-6 Cale No. SO1-207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 9 of 29 SONGS U1 GTCC dose calculation [Reference 5.3] addresses the Unit 1 GTCC canister by noting its off-site dose contribution is bounded by a 24PT-1 DSC loaded with Unit 1 design basis spent nuclear fuel assemblies. The assumption that all DSCs are loaded to the design value is a conservative assumption .

Reference 5.2 includes doses for AHSM installations in seven phases. As shown in Sections 4.6 and 4.7, the existing TN ISFSI inventory of seventeen (17) 24PT1 DSCs containing SONGS Unit 1 spent nuclear fuel and thirty-three (33) 24PT4 DSCs containing SONGS Units 2&3 spent nuclear fuel falls within Phase 3 and Phase 4. For this calculation, the higher dose from these two phases will be used . This approach conservatively ignores the source decay between Phase 3 (2011) and Phase 4 (2014) . Furthermore, its use in this calculation conservatively ignores the source-term decay since 2014 to the present (2021 ). Bounding dose points were selected to address doses at the 100-meter perimeter, the proposed post-exemption CAB, and in areas beyond the SONGS OCA that may allow unrestricted occupancy.

Doses at various dose points were calculated in Reference 5.2 as listed in Reference 5.2 Table 9-2 for Phase 3 and Reference 5.2 Table 9-3 for Phase 4.

Reference 5.2 Table 4-10 indicates the onsite dose points are Detectors 1 through 10.

Reference 5.2 Table 4-11 indicates the 100-meter dose points are Detectors 11 through 21.

Detector 17 is closest to the nuisance fence as shown in Attachment D of Reference 5.2.

Reference 5.2 Table 4-12 indicates the EAB dose points are Detectors 22 through 28. The EAB dose will be used for areas beyond the north OCA fence since the fence coincides with the EAB.

Reference 5.2 Attachment D shows a dose location (Detector 1) at the railroad by Interstate Highway 1-5. The annual dose at this location is conservatively used for areas east of the Owner Controlled Area (OCA) that may allow unrestricted occupancy.

Reference 5.2 Tables 9-2 and 9-3 indicates that Detectors 1 through 10 are based on an annual occupancy factor of 2080 hours0.0241 days 0.578 hours 0.00344 weeks 7.9144e-4 months and that Detectors 11 through 28 are based on an annual occupancy factor of 8760 hours0.101 days 2.433 hours 0.0145 weeks 0.00333 months .

As shown in Attachment D of Reference 5.2 , the west side of the 100-meter perimeter is reduced to align with the NIA seawall. Compared with the expanded ISFSI facility shown in Figure 1.2, the 100-meter perimeter considered in the TN calculation is smaller and is enclosed within it. However, it is conservative to use the TN 100-meter perimeter values for the expanded perimeter. Therefore, the proposed post-exemption CAB will have the same dose value for storage of spent nuclear fuel and GTCC in TN AHSMs.

2.3.2 Annual Doses from GTCC Storage in the TN ISFSI The Units 2/3 GTCC Storage dose calculation [Reference 5.4] provides annual doses for planned storage of up to 12 Units 2&3 GTCC containers (RWC-WA) in AHSM 's within the existing array on the eastern portion of the ISFSI. As in the case noted above, this input calculation assumes the dose from these GTCC storage systems is the same as that for spent nuclear fuel in a DSC within an AHSM .

Reference 5.4 Table 9-5 provides the 100-meter dose contributions .

Reference 5.4 Table 9-4 provides doses at EAB and Detector 1.

Reference 5.4 Section 3.0 states that the detector locations and occupancy factors are consistent with those described in the existing TN ISFSI storage dose calculation [Reference 5.2) (see preceding Section 2.3.1 ).

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1-207-1 -C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 10 of 29 2.4 Doses Due to Storage of Spent Nuclear Fuel in Holtec UMAX Storage Systems The Holtec ISFSI storage and transfer dose calculation [Reference 5.6) provides annual doses at on-site and off-site locations due to radiation shine from the spent fuel stored at a fully loaded Holtec ISFSI containing 73 canisters (Reference 5.6 Section 7 .1).

The detectors are depicted in Reference 5.6 Figure 1. The HOLTEC ISFSI stored spent nuclear fuel dose contributions at the detectors are presented in Reference 5.6 Table 4. Reference 5.6 Table 3 provides the modeled occupancy hours for the doses presented in Reference 5.6 Table 4.

2.5 Doses Due to Canister Transfer For this analysis to assist in planning for future transfer of dry storage canisters (TN DSC, GTCC RWC-WA, and Holtec MPC) offsite, the limiting scenario is to transfer a number of casks containing Holtec multi-purpose canisters (MPCs) from the existing storage configuration . This is because Holtec MPCs generally have more activity content (i .e., more fuel assemblies and shorter cooling time) and the vertical mode of Holtec MPC transfer can result in a higher dose at the Control Area Boundary with the western boundary the most impacted .

The transfer of MPCs involves stack-up of HI-TRAC at the Vertical Ventilated Module (WM) containing an MPC to be removed. The MPC is then withdrawn into the HI-TRAC and the HI-TRAC with its MPC load is transferred to a location onsite to stack-up and download the MPC into a HI-STAR transportation cask. The operation is similar to the MPC Download Operation that transferred MPCs into the WM. Therefore, for this scoping analysis, the MPC Download Operation dose calculation will be used to estimate the dose for MPC transfer from a WM to a HI-STAR transportation cask.

Holtec Report No. Hl-2177793 (Reference 5.6) provides annual doses at on-site and off-site locations from the transfer of MPCs. Reference 5.6 Table 1 states that the EAB is represented by Detectors 22 through 28 . The analysis conservatively assumes all 73 MPCs onsite were transferred within one year. The duration of each MPC transfer (including stack-up and download) is conservatively assumed to be 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months . The analysis conservatively assumes that the MPC within the HI-TRAC is one foot above the WM for the entire 12-hour duration .

Reference 5.6 Table 7 presents the average dose rates of combined transfer of all 73 MPCs at the same locations described in Section 2.4. These dose rates are calculated with an assumed 50%

deterioration in the seawall. These dose rates , as summarized in Table 2.5.1, will be used to calculate the annual dose due to canister transfer.

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1 -207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 11 of 29 Table 2.5.1 Dose Rate from Transfer of a Single MPC Detector Dose Rate, 2, 3 Number(s) mremlhr 29, 30, 31, 40 6_89E~02 32, 33, 34 2_98E-02 35, 36, 37 2.25E -02 2, 3, 4 1_33E ~02 25,26, 27,28 l _SOE-03 4 1, 42 l -34E _,02 22, 23, 24 8-15E-04 38 2_96E-01 39 4_06E~02 10, 11 l _62E-.!02 43 L 31E~Ol 5, 6 7_02E~03 1,7.8, 9 9_81E_,Q3

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1-207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 12 of 29 3.0 Calculations 3.1 Doses Due to Storage of Spent Nuclear Fuel in the TN ISFSI The TN ISFSI storage dose calculation [Reference 5.2] provides annual doses at on-site and off-site locations due to radiation shine from the spent fuel stored at the TN ISFSI.

Section 2.3.1 presents input associated with the Reference 5.2 evaluation of doses due to storage of spent nuclear fuel in the TN ISFSI.

Table 3.1.1 identifies the detectors that are used to evaluate the proposed post-exemption CAB for spent nuclear fuel stored in the TN ISFSI. Table 3.1.1 also identifies the location of each detector relative to the TN ISFSI. Each of these detectors is either at the post-exemption CAB or conservatively situated between the TN ISFSI and post-exemption CAB .

Table 3.1.1 TN ISFSI Detectors Representing Post-Exemption CAB LOCATION DETECTORS OCCUPANCY FACTOR WITH RESPECT TO (hours/year per Section 2.2)

TN ISFSI Northwest 7, 13 20 (on the bluff, not on the beach)

North 2, 7, 14, 15, 16 20 Northeast 2, 15, 16 20 (same as north and east)

East 2, 3, 4, 16, 18 20 Southeast 4, 18, 19, 20 20 (same as south and east)

South 4,20, 21 20 Southwest 11 20 (same as south, not on the beach)

West 11, 12, 13 300 (on the beach)

Using the approach outlined in Section 2.3.1 , annual doses at the Table 3.1.1 locations are derived in Table 3.1.2. The following is a sample calculation for Detector 11 towards the WEST:

Detector 11 adjusted annual dose = (4.25 mrem) x (300 hrs / 8760 hrs) = 0.15 mrem Table 3.1.2 uses a BOLD font to highlight the maximum TN AHSM spent nuclear fuel storage doses at the post-exemption CAB (restricted occupancy), EAB (unrestricted occupancy), and the Railroad by Interstate Highway 1-5 (unrestricted occupancy).

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1-207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 13 of 29 Table 3.1.2 Summary of TN ISFSI Stored Spent Nuclear Fuel Dose Contributions Detector location Phase 3 Phase 4 Greater of Modeled Desired Adjusted with respect to Fuel Dose Fuel Dose Phases 3 and 4 Occupancy Occupancy Fuel Dose TN ISFSI mrem/year mrem/year mrem/year Hours Hours mrem/year POST-EXEMPTION CAB 2 N, NE, E 10.85 8.07 10.85 2080 20 0.10 3 E 4.85 5.29 5.29 2080 20 0.05 4 E, SE, S 2.20 2.68 2.68 2080 20 0.03 7 N, NW 7.89 6.89 7.89 2080 20 0.08 11 SW 4.23 4.25 4.25 8760 20 0.01 11 w 4.23 4.25 4.25 8760 300 0.15 12 w 14.06 13.39 14.06 8760 300 0.48 13 w 17.53 17.88 17.88 8760 300 0.61 13 NW 17.53 17.88 17.88 8760 20 0.04 14 N 7.61 6.94 7.61 8760 20 0.02 15 N, NE 6.94 6.00 6.94 8760 20 0.02 16 N, NE, E 8.64 7.32 8.64 8760 20 0.02 18 E, SE 3.64 4.53 4.53 8760 20 0.01 19 SE 3.13 3.99 3.99 8760 20 0.01 20 SE, S 2.73 3.25 3.25 8760 20 0.01 21 s 2.32 2.61 2.61 8760 20 0.01 EAB 22 0.53 0.49 0.53 8760 8760 0.53 23 0.54 0.49 0.54 8760 8760 0.54 24 0.62 0.57 0.62 8760 8760 0.62 25 0.47 0.43 0.47 8760 8760 0.47 26 0.37 0.36 0.37 8760 8760 0.37 27 0.28 0.29 0.29 8760 8760 0.29 28 0.23 0.23 0.23 8760 8760 0.23 RAILROAD BY INTERSTATE HIGHWAY 1-5 1 E 1.03 1.23 1.23 2080 8760 5.18 3.2 Doses Due to Storage of GTCC in the TN ISFSI The Units 2/3 GTCC Storage dose calculation [Reference 5.4) provides annual doses for planned storage of up to 12 Units 2&3 GTCC containers (RWC-WA) in AHSM 's within the existing array on the eastern portion of the ISFSI.

Section 2.3.2 presents input associated with the Reference 5.2 evaluation of doses due to storage of GTCC in the TN ISFSI.

Table 3.1.1 identifies the detectors that are used to evaluate the proposed post-exemption CAB.

Table 3.1.1 also identifies the location of each detector relative to the TN ISFSI. Each of these detectors is either at the post-exemption CAB or conservatively situated between the TN ISFSI and post-exemption CAB .

Figure 3.2.1 depicts the location of Detectors 1, 2, 3, 4, 16, 17, and 18 as modeled in the TN ISFSI storage dose calculation (Reference 5.2 Attachment D) .

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1-207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 14 of 29 Figure 3.2.1. Detectors on East Side of the TN ISFSI Detector 1 is addressed in both the TN ISFSI storage dose calculation and the Units 2/3 GTCC storage dose calculation (modeled in each calculation with the same occupancy factor of 2080 hours0.0241 days 0.578 hours 0.00344 weeks 7.9144e-4 months per year). Detectors 16, 17, and 18 are addressed in both the TN ISFSI storage dose calculation and the Units 2/3 GTCC storage dose calculation (modeled in each calculation with the same occupancy factor of 8760 hours0.101 days 2.433 hours 0.0145 weeks 0.00333 months per year) .

Detectors 2, 3, and 4 are not addressed in the Units 2/3 GTCC storage dose calculation . Since the GTCC waste is stored with the spent nuclear fuel at the TN ISFSI , the ratios for the GTCC dose with respect to the stored spent nuclear fuel at Detectors 1, 16, 17, and 18 can be applied to determine the GTCC dose at Detectors 2, 3, and 4. As shown in Table 3.2.1 , the maximum ratio of the GTCC dose to the stored spent nuclear fuel dose at Detectors 1, 16, 17, and 18 is 0.558 (i.e.,

56%). This maximum ratio is applied to the stored spent nuclear fuel dose at Detectors 2, 3, and 4 (per Table 3.1.2) with an occupancy factor of 2080 hours0.0241 days 0.578 hours 0.00344 weeks 7.9144e-4 months per year to estimate the GTCC dose at Detectors 2, 3, and 4 with an occupancy factor of 2080 hours0.0241 days 0.578 hours 0.00344 weeks 7.9144e-4 months per year.

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1-207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 15 of 29 Table 3.2.1 Estimation of GTCC Dose at Detectors 2, 3, and 4 Detector Fuel Dose GTCC Dose Ratio of GTCC Dose mrem/year mrem/year to Fuel Dose 1 (Phase 3) 1.03 0.45 0.437 1 (Phase 4) 1.23 0.45 0.366 16 (Phase 3) 8.64 1.77 0.205 16 (Phase 4) 7.32 1.77 0.242 17 (Phase 3) 6.92 3.11 0.449 17 (Phase 4) 8.40 3.11 0.370 18 (Phase 3) 3.64 2.03 0.558 18 (Phase 4) 4.53 2.03 0.448 Detector Fuel Dose Maximum Ratio of GTCC Dose GTCC Dose mrem/year to Fuel Dose mrem/year 2 10.85 0.558 6.05 3 5.29 0.558 2.95 4 2.68 I 0.558 f 1.49 Figure 3.2.2 depicts the location of Detectors 7 and 13 as modeled in the TN ISFSI Storage dose calculation (Reference 5.2 Attachment D) .

Figure 3.2.2. Detectors on Northwest and West Sides of the TN ISFSI

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1-207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 16 of 29 Detector 13 is at the ISFSI fence, near the seawall on the west side of the TN ISFSI at Elevation 17 feet (i.e., approximately the same as the TN ISFSI elevation) . There is little shielding between the TN ISFSI and Detector 13. Detector 13 is addressed in both the TN ISFSI storage dose calculation and the Units 2/3 GTCC storage dose calculation .

Detector 7 is on the northwest side of the TN ISFSI at Elevation 86 feet (i.e., on the bluff) . Detector 7 is not addressed in the Units 2/3 GTCC storage dose calculation . Since the GTCC waste is stored with the fuel at the TN ISFSI , the ratio for the GTCC dose with respect to the stored spent nuclear fuel at Detector 13 can be applied to determine the GTCC dose at Detector 7. As shown in Table 3.2 .2, the ratio of the GTCC dose to the stored spent nuclear fuel dose at Detector 13 is 0.322 (i.e. , 32%). This ratio is applied to the stored spent nuclear fuel dose at Detector 7 (per Table 3.1.2) to estimate the GTCC dose at Detector 7.

Table 3.2.2 Estimation of GTCC Dose at Detector 7 Detector Fuel Dose GTCC Dose Ratio of GTCC Dose mrem/year mrem/year to Fuel Dose 13 (Phase 3) 17.53 5.640 0.322 13 (Phase 4) 17.88 5.640 0.315 Detector Fuel Dose Maximum Ratio of GTCC Dose GTCC Dose mrem/year to Fuel Dose mrem/year 7 7.89 0.322 2.54 Using the same occupancy factor scaling approach taken in Section 3.1, SONGS 2/3 GTCC doses are derived in Table 3.2.3. Table 3.2.3 uses a BOLD font to highlight the maximum TN AHSM GTCC storage doses at the post-exemption CAB (restricted occupancy) , EAB (unrestricted occupancy), and the Railroad by Interstate Highway 1-5 (unrestricted occupancy) .

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1 -207-1 -C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 17 of 29 Table 3.2.3 Summary of SONGS 2/3 GTCC Dose Contributions Detector Location GTCC Dose Modeled Desired Adjusted with respect to Occupancy Occupancy GTCC Dose TN ISFSI mrem/year Hours Hours mrem/year POST-EXEMPTION CAB 2 N, NE, E 6.05 2080 20 0.06 3 E 2.95 2080 20 0.03 4 E, SE, S 1.49 2080 20 0.01 7 N, NW 2.54 2080 20 0.02 11 SW 1.32 8760 20 0.00 11 w 1.32 8760 300 0.05 12 w 4.95 8760 300 0.17 13 w 5.64 8760 300 0.19 13 NW 5.64 8760 20 0.01 14 N 1. 66 8760 20 0.00 15 N, NE 1.35 8760 20 0.00 16 N, NE, E 1.77 8760 20 0.00 18 E, SE 2.03 8760 20 0.00 19 SE 1.78 8760 20 0.00 20 SE, S 1.55 8760 20 0.00 21 s 1.33 8760 20 0.00 EAB 0.52 8760 8760 0.52 RAILROAD BY INTERSTATE HIGHWAY 1-5 1 E 0.45 2080 8760 1.90 3.3 Doses Due to Storage of S12ent Nuclear Fuel in the Holtec ISFSI The Holtec ISFSI storage and transfer dose calculation [Reference 5.6] provides annual doses at on-site and off-site locations due to radiation shine from the spent fuel stored at the fully loaded Holtec ISFSI containing 73 canisters .

Section 2.4 presents input associated with the Reference 5.6 evaluation of doses due to storage of spent nuclear fuel in the Holtec ISFSI.

Table 3.3.1 identifies the detectors that are used to evaluate the proposed post-exemption CAB for doses due to storage of spent nuclear fuel in the Holtec ISFSI and due to canister transfers . With the exception of Detectors 7, 8, and 9, each of these detectors is either at the post-exemption CAB or conservatively situated between the Holtec ISFSI and post-exemption CAB. Relative to the Holtec ISFSI , Detectors 7, 8, and 9 are more distant than the post-exemption CAB in the East direction .

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1-207-1 -C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 18 of 29 Detectors 29, 40, and 43 as used as surrogates for the bluff location to the northwest of the ISFSI.

It is noted that Detectors 29 and 40 are closer to the Holtec ISFSI than Detector 43. Detector 40 is between the ISFSI and post-exemption CAB.

Detectors 2, 3, 4, 25, 26, 27, 28, 32 , 33, 34, 35, 36, and 37 are not considered , since they are further west from the ISFSI than Detectors 29 , 30 , 31 , and 40.

Detectors 22, 23, and 24 are not considered, since they are further north from the ISFSI than Detectors, 5, 6, 41, 42, and 43.

Table 3.3.1 HOLTEC ISFSI Detectors Representing Post-Exemption CAB LOCATION DETECTORS OCCUPANCY FACTOR WITH RESPECT TO (hours/year per Section 2.2)

HOLTEC ISFSI Northwest 29,40, 43 20 North 5,6,41,42,43 20 Northeast 6 20 (same as north and east)

East 7, 8, 9 20 Southeast 10,39 20 (same as south and east)

South 10, 11, 38, 39 20 Southwest 31 20 West 29,30,31, 40 300 (on the beach)

It is noted that the TN ISFSI is located between the Holtec ISFSI and the post-exemption CAB in the East direction . Per Figure 3.2 .1, the TN ISFSI storage dose calculation determines annual doses to the east of the TN ISFSI (i.e., at Detectors 1, 2, 3, and 4) based on an occupancy factor of 2080 hours0.0241 days 0.578 hours 0.00344 weeks 7.9144e-4 months per year. Detector 1 is at the Railroad by Interstate Highway 1-5. This same Railroad detector is also evaluated in the Holtec ISFSI storage and transfer dose calculation [Reference 5.6] .

As shown in Table 3.3.2, the maximum ratio of the TN ISFSI stored spent nuclear fuel dose at Detectors 2, 3, and 4 (for 2080 hours0.0241 days 0.578 hours 0.00344 weeks 7.9144e-4 months per year) with respect to the TN ISFSI stored spent nuclear fuel dose at Detector 1 (for 2080 hours0.0241 days 0.578 hours 0.00344 weeks 7.9144e-4 months per year) is 10.53 (i.e., 1053%). Therefore, the Holtec ISFSI stored spent nuclear fuel annual dose at locations equivalent to TN ISFSI storage dose calculation

[Reference 5.2) Detectors 2, 3, and 4 is approximately 10.53 times greater than the Holtec ISFSI stored spent nuclear fuel annual dose at Detector 1. This maximum ratio is applied to the Holtec stored spent fuel dose at Holtec Detector 1 with an occupancy factor of 300 hours0.00347 days 0.0833 hours 4.960317e-4 weeks 1.1415e-4 months per year to estimate the Holtec stored spent fuel dose at TN Detector locations 2, 3, and 4 with an occupancy factor of 300 hours0.00347 days 0.0833 hours 4.960317e-4 weeks 1.1415e-4 months per year.

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1-207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 19 of 29 Table 3.3.2 Estimation of Holtec Stored Spent Fuel Dose at East CAB TN ISFSI TN ISFSI Ratio of Maximum Fuel Dose Minimum Fuel Dose Detector 2 Dose During Phases 3 & 4 During Phases 3 & 4 to Detector 1 Dose Detector 2 Detector 1 mrem/year mrem/year 10.85 1.03 10.53 I

TN ISFSI TN ISFSI Ratio of Maximum Fuel Dose Minimum Fuel Dose Detector 3 Dose During Phases 3 & 4 During Phases 3 & 4 to Detector 1 Dose Detector 3 Detector 1 mrem/year mrem/year 5.29 1.03 5.14 I

I l

TN ISFSI TN ISFSI Ratio of Maximum Fuel Dose Minimum Fuel Dose Detector 4 Dose During Phases 3 & 4 During Phases 3 & 4 to Detector 1 Dose Detector4 Detector 1 mrem/year mrem/year 2.68 1.03 2.60 I

Holtec ISFSI Maximum Ratio of Holtec ISFSI Fuel Dose at Detector 2, 3, 4 Doses Fuel Dose at Detector 1 to Detector 1 Dose TN 2, 3, 4 mrem/year mrem/year 0.3 I 10.53 3.16 Table 3.3.3 summarizes the HOLTEC ISFSI stored spent nuclear fuel dose contributions as presented in the preceding Table 3.3.2 and in Reference 5.6 Table 4. Reference 5.6 Table 3 provides the modeled occupancy hours for the doses presented in Reference 5.6 Table 4.

Reference 5.6 Table 1 states that the EAB is represented by Detectors 22 through 28.

Using the same occupancy factor scaling approach taken in Sections 3.1 and 3.2, doses due to storage of spent nuclear fuel in the Holtec ISFSI are derived in Table 3.3.3. Table 3.3.3 uses a BOLD font to highlight the maximum Holtec spent nuclear fuel storage doses at the post-exemption CAB (restricted occupancy), EAB (unrestricted occupancy), and the Railroad by Interstate Highway 1-5 (unrestricted occupancy) .

- - -- -- -- - -- - - - - - - - - - - - - - - - - - - - - - - - - ~

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1 -207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 20 of 29 Table 3.3.3 Summary of Holtec ISFSI Stored Spent Nuclear Fuel Dose Contributions Detector Location Fuel Dose Modeled Desired Adjusted with respect to Occupancy Occupancy Fuel Dose Holtec ISFSI mrem/year Hours Hours mrem/year POST-EXEMPTION CAB TN 2, 3, 4 E 3.16 300 20 0.21 2 SW 0.64 300 20 0.04 5 N 1.08 500 20 0.04 6 N,NE 1.06 500 20 0.04 7 E 0.36 300 20 0.02 8 E 0.39 300 20 0.03 9 E 0.44 300 20 0.03 10 S,SE 2.38 2000 20 0.02 11 s 3.70 2000 20 0.04 29 NW 4.40 300 20 0.29 29 w 4.40 300 300 4.40 30 w 6.00 300 300 6.00 31 w 5.43 300 300 5.43 31 SW 5.43 300 20 0.36 38 s 27.51 2000 20 0.28 39 S, SE 7.73 2000 20 0.08 40 w 40.86 2000 300 6.13 40 NW 40.86 2000 20 0.41 41 N 8.28 2000 20 0.08 42 N 2.84 2000 20 0.03 43 N,NW 4.71 500 20 0.19 EAB Maximum of 22 to 28 0.05 300 8760 1.46 RAILROAD BY INTERSTATE HIGHWAY 1-5 1 E 0.30 300 8760 8.76

\

3.4 Total Annual Doses due to Storage of S12ent Fuel and GTCC Table 3.4.1 provides the calculation of annual doses at locations at and beyond the post-exemption CAB due to storage of spent nuclear fuel and GTCC in the SONGS ISFSI. The post-exemption CAB location is at or within the 1DO-meter perimeter; therefore, the 1DO-meter perimeter annual dose is conservatively represented by the post-exemption CAB dose.

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1-207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 21 of 29 Total doses are calculated by summing the storage doses from :

Storage of Spent Nuclear Fuel in the TN ISFSI (per Section 3.1)

Storage of GTCC in the TN ISFSI (per Section 3.2)

Storage of Spent Nuclear Fuel in the Holtec ISFSI (per Section 3.3)

The annual doses at the post-exemption CAB reflect restricted access as defined by the occupancy factors specified in Section 2.2 (i.e., 20 hours2.314815e-4 days 0.00556 hours 3.306878e-5 weeks 7.61e-6 months to the North , East, and South , and 300 hours0.00347 days 0.0833 hours 4.960317e-4 weeks 1.1415e-4 months to the West) .

The annual doses at the EAB and at railroad by Interstate Highway 1-5 locations beyond the post-exemption CAB allow for unrestricted access (i.e., 8760 hours0.101 days 2.433 hours 0.0145 weeks 0.00333 months per year).

A review of Table 3.4 .1 and its supporting Sections 3.1, 3.2, and 3.3 show that that the doses that are West of the ISFSI (with its 300 hours0.00347 days 0.0833 hours 4.960317e-4 weeks 1.1415e-4 months per year occupancy factor) are the dominating doses at the post-exemption CAB .

The annual storage doses at and beyond the post-exemption CAB are less than the 10 CFR 72 .104 limit of 25 mrem/year.

NOTE: The total annual doses due to storage are calculated with an Excel spreadsheet leading to potential round-off discrepancies.

Table 3.4.1 Total Storage Related Annual Whole Body Doses (in mrem/year)

At and Beyond the Post-Exemption Controlled Area Boundary Annual Dose Annual Dose Annual Dose CAB EAB RR near 1-5 Restricted Access Unrestricted Access Unrestricted Access mrem/year mrem/year mrem/year TN ISFSI Fuel Storage Dose 0.61 0.62 5.18 TN ISFSI GTCC Storage Dose 0.19 0.52 1.90 Holtec Fuel Storage Dose 6.13 1.46 8.76 Total Storage Dose 6.93 2.60 15.84 10CFR 72.104 Limit 25 25 25 3.5 Doses Due to Canister Transfer Holtec Report No. Hl-2177793 (Reference 5.6) provides annual doses at on-site and off-site locations due to the transfer of MPCs.

Section 2.5 presents input associated with the Reference 5.6 evaluation of doses due to canister transfer.

Table 3.3.1 identifies the detectors that are used to evaluate the proposed post-exemption CAB for doses due to storage of spent nuclear fuel in the Holtec ISFSI and due to canister transfers. As in Section 3.3, it is noted that the TN ISFSI is located between the Holtec ISFSI and the post-exemption CAB in the East direction . Per Figure 3.2.1, the TN ISFSI storage dose calculation determines annual doses to the east of the TN ISFSI (i.e., at Detectors 1, 2, 3, and 4) based on an occupancy factor of 2080 hours0.0241 days 0.578 hours 0.00344 weeks 7.9144e-4 months per year. Detector 1 is at the Ra ilroad by Interstate Highway 1-5.

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1-207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 22 of 29 This same Railroad detector is also evaluated in the Holtec ISFSI storage and transfer dose calculation [Reference 5.6) .

As documented in Section 3.3 and Table 3.3.2, the maximum ratio of the TN ISFSI stored spent nuclear fuel dose at Detectors 2, 3, and 4 (for 2080 hours0.0241 days 0.578 hours 0.00344 weeks 7.9144e-4 months per year) with respect to the TN ISFSI stored spent nuclear fuel dose at Detector 1 (for 2080 hours0.0241 days 0.578 hours 0.00344 weeks 7.9144e-4 months per year) is 10.53 (i.e., 1053%).

Therefore, the canister transfer dose at locations equivalent to TN ISFSI storage dose calculation

[Reference 5.2) Detectors 2, 3, and 4 is approximately 10.53 times greater than the canister transfer dose at Detector 1. The scaling to determine the canister transfer dose at TN Detector locations 2, 3, and 4 is documented in Table 3.5.1.

Table 3.5.1 Estimation of Transfer Dose at East CAB Holtec ISFSI Maximum Ratio of Holtec ISFSI Transfer DR at Detector 2, 3, or 4 to 1 Transfer DR at Detector 1 Dose TN 2, 3, 4 mrem/hour mrem/hour 0.00981 10.53 0.1033 Per Section 2.2, the maximum exposure to canister transfer is limited to 20 hours2.314815e-4 days 0.00556 hours 3.306878e-5 weeks 7.61e-6 months per year for individuals at North , East, and South locations, irrespective as to how many canister transfers are performed in a year.

Two cases are presented in this section . The first case assumes transfer of 20 canisters per year and the second case assumes transfer of 25 canisters per year. For the first case , the transfer of 20 canisters results in a maximum of 240 hours0.00278 days 0.0667 hours 3.968254e-4 weeks 9.132e-5 months of annual exposure near the accessible locations near the seawall and 20 hours2.314815e-4 days 0.00556 hours 3.306878e-5 weeks 7.61e-6 months elsewhere. For the second case , the transfer of 25 canisters results in a maximum of 300 hours0.00347 days 0.0833 hours 4.960317e-4 weeks 1.1415e-4 months of annual exposure per year near the accessible locations near the seawall and 20 hours2.314815e-4 days 0.00556 hours 3.306878e-5 weeks 7.61e-6 months elsewhere.

Tables 3.5.2 and 3.5.3 provide the calculation of transfer doses for 20 and 25 canister transfers, respectively . Tables 3.5.2 and 3.5.3 use a BOLD font to highlight the maximum canister transfer doses at the post-exemption CAB (restricted occupancy) , EAB (unrestricted occupancy) , and the Railroad by Interstate Highway 1-5 (unrestricted occupancy).

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1-207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 23 of 29 Table 3.5.2 Annual Dose due to Transfer of 20 Canisters Detector Location Fuel Dose Modeled Desired Adjusted with respect to Occupancy Occupancy Fuel Dose Holtec ISFSI mrem/year Hours Hours mrem/year POST-EXEMPTION CAB TN 2, 3, 4 E 3.16 300 20 0.21 2 SW 0.64 300 20 0.04 5 N 1.08 500 20 0.04 6 N,NE 1.06 500 20 0.04 7 E 0.36 300 20 0.02 8 E 0.39 300 20 0.03 9 E 0.44 300 20 0.03 10 S, SE 2.38 2000 20 0.02 11 s 3.70 2000 20 0.04 29 NW 4.40 300 20 0.29 29 w 4.40 300 300 4.40 30 w 6.00 300 300 6.00 31 w 5.43 300 300 5.43 31 SW 5.43 300 20 0.36 38 s 27.51 2000 20 0.28 39 S,SE 7.73 2000 20 0.08 40 w 40.86 2000 300 6.13 40 NW 40.86 2000 20 0.41 41 N 8.28 2000 20 0.08 42 N 2.84 2000 20 0.03 43 N, NW 4.71 500 20 0.19 EAB Maximum of 22 to 28 0.05 300 8760 1.46 RAILROAD BY INTERSTATE HIGHWAY 1-5 1 E 0.30 300 8760 8.76

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1-207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 24 of 29 Table 3.5.3 Annual Dose due to Transfer of 25 Canisters Detector Location Dose Rate Maximum 25 Transfers Occupancy Adjusted Dose with respect to per Transfer Occupancy for 20 Transfers for 25 Transfers Holtec ISFSI mrem/hr hours/year hours/year hours/year mrem/year POST-EXEMPTION CAB TN 2, 3, 4 E 0.1033 20 300 20 2.07 2 SW 0.0133 20 300 20 0.27 5 N 0.00702 20 300 20 0.14 6 N,NE 0.00702 20 300 20 0.14 7 E 0.00981 20 300 20 0.20 8 E 0.00981 20 300 20 0.20 9 E 0.00981 20 300 20 0.20 10 S, SE 0.0162 20 300 20 0.32 11 s 0.0162 20 300 20 0.32 29 NW 0.0689 20 300 20 1.38 29 w 0.0689 300 300 300 20.67 30 w 0.0689 300 300 300 20.67 31 w 0.0689 300 300 300 20.67 31 SW 0.0689 20 300 20 1.38 38 s 0.2960 20 300 20 5.92 39 S, SE 0.0406 20 300 20 0.81 40 w 0.0689 300 300 300 20.67 40 NW 0.0689 20 300 20 1.38 41 N 0.0134 20 300 20 0.27 42 N 0.0134 20 300 20 0.27 43 N, NW 0.1310 20 300 20 2.62 EAB (Max of 22 to 28) 0.00150 300 300 300 0.45 RAILROAD BY INTERSTATE HIGHWAY 1-5 1 E 0.00981 300 300 300 2.94 3.6 Total Annual Doses Due to Both Storage and Canister Transfer To provide reasonable assurance that future canister transfer operations can be accommodated without exceeding the 10 CFR 72 .104 annual dose limit of 25 mrem , this section present two sensitivity cases. The first case assumes a transfer of 20 canisters in the first year. The second case assumes a transfer of 25 canisters in the first year.

The maximum canister transfer doses from Section 3.5 are combined with the maximum storage doses from Section 3.4 . The total annual dose from the transfer of 20 canisters and 25 canisters are presented in Tables 3.6.1 and 3.6.2, respectively . The total storage and canister transfer doses are calculated at the post-exemption CAB (restricted occupancy), EAB (unrestricted occupancy),

and the Railroad by Interstate Highway 1-5 (unrestricted occupancy).

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1-207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 25 of 29 Per Section 2.4, the maximum storage doses calculated in Section 3.4 consider an annual dose due to the storage of a fully loaded HOLTEC ISFSI containing 73 canisters . During transfer options, a quantity of these canisters are off-loaded from the ISFSI , such that by the end of the year there are fewer canisters stored at the HOLTEC ISFSI, resulting in a decrease in what was the storage dose at the beginning of the year. The Holtec storage dose is updated to reflect the number of Holtec canisters transferred out. The updated Holtec storage dose is the average of the Holtec storage doses at the beginning of the year (BOY) and the end of the year (EOY).

A review of Table 3.6.1 shows that a transfer of 20 canisters in the first year results in annual storage plus transfer doses at and beyond the post-exemption CAB that are less than the 10 CFR 72.104 limit of 25 mrem/year.

A review of Table 3.6.2 shows that a transfer of 25 canisters in the first year results in an annual storage plus transfer dose at the post-exemption CAB that is greater than the 10 CFR 72 .104 limit of 25 mrem/year. A review of Table 3.6.2 shows that a transfer of 25 canisters in the first year results in annual storage plus transfer doses at the EAB and at the railroad near Interstate Highway 1-5 that are less than the 10 CFR 72.104 limit of 25 mrem/year.

NOTE: The total annual doses due to storage and canister transfer are calculated with an Excel spreadsheet leading to potential round-off discrepancies.

Table 3.6.1 Total Annual Dose due to Storage and Transfer of 20 Canisters

Transfers per year= 20 Annual Dose Annual Dose Annual Dose CAB EAB RR near 1-5 Restricted Access Unrestricted Access Unrestricted Access mrem/year mrem/year mrem/year TN ISFSI Fuel Storage Dose 0.61 0.62 5.18 TN ISFSI GTCC Storage Dose 0.19 0.52 1.90 Holtec Fuel Storage Dose 6.13 1.46 8.76 Total Storage Dose at BOY 6.93 2.60 15.84 Total Storage Dose at EOY 5.26 2.20 13.44 Average Storage Dose 6.09 2.40 14.64 Holtec Transfer Dose 16.54 0.36 2.35 TOTAL DOSE: 22.63 2.76 16.99

CALCULATION SHEET NECP No . 0820-75665-6 Cale No. SO1 -207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE. CALCULATION Page 26 of 29 Table 3.6.2 Total Annual Dose due to Storage and Transfer of 25 Canisters

Transfers per year= 25 Annual Dose Annual Dose Annual Dose CAB EAB RR near 1-5 Restricted Access Unrestricted Access Unrestricted Access mrem/year mrem/year mrem/year TN ISFSI Fuel Storage Dose 0.61 0.62 5.18 TN ISFSI GTCC Storage Dose 0.19 0.52 1.90 Holtec Fuel Storage Dose 6.13 1.46 8.76 Total Storage Dose at BOY 6.93 2.60 15.84 Total Storage Dose at EOY 4.84 2.10 12.84 Average Storage Dose 5.88 2.35 14.34 Holtec Transfer Dose 20.67 0.45 2.94 TOTAL DOSE: 26.55 2.80 17.28

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1-207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY I.SFSI DOSE CALCULATION Page 27 of 29 4.0 Results As shown in Table 3.4 .1, the maximum annual dose from the storage of spent fuel and GTCC at SONGS ISFSI at the post-exemption CAB (See Figure 1.3) are within the 10 CFR 72 .104 annual limit of 25 mrem . The Northwest, North , Northeast, East, Southeast, South , and Southwest borders of the post-exemption CAB are modeled with a restricted occupancy of 20 hours2.314815e-4 days 0.00556 hours 3.306878e-5 weeks 7.61e-6 months per year. The West border of the post-exemption CAB is modeled with a restricted occupancy of 300 hours0.00347 days 0.0833 hours 4.960317e-4 weeks 1.1415e-4 months per year.

Table 3.4 .1 also documents that the maximum annual storage dose of spent fuel and GTCC at the ISFSI at locations beyond the post-exemption CAB (i.e., at the EAB and the railroad near Interstate Highway 1-5) are also within the 10 CFR 72 .104 annual limit of 25 mrem . These locations are modeled with an unrestricted occupancy of 8760 hours0.101 days 2.433 hours 0.0145 weeks 0.00333 months per year.

It should be noted that 72.104 includes:

(a) Planned discharges of radioactive materials, radon and its decay products excepted, to the general environment, (b) Direct radiation from ISFSI or MRS operations, and (c) Any other radiation from uranium fuel cycle operations within the region.

This calculation explicitly treats direct radiation. There are no planned effluents or discharges from the ISFSI. The only other direct radiation sources are from the balance of the plant site which is routinely monitored and shown to be minimal at the Site. These other two potential contributors are also implicitly bounded by the conservatisms noted in Section 4.1.

To provide reasonable assurance that future canister transfer operations can be accommodated without exceeding the 10 CFR 72.104 annual dose limit of 25 mrem , two sensitivity cases are presented in Section 3.6. Table 3.6.1 presents the first case which assumes a transfer of 20 canisters in the first year. Table 3.6.2 presents the second case which assumes a transfer of 25 canisters in the first year.

A review of Table 3.6 .1 shows that a transfer of 20 canisters in the first year results in annual storage plus transfer doses at and beyond the post-exemption CAB that are less than the 10 CFR 72.104 limit of 25 mrem/year.

A review of Table 3.6.2 shows that a transfer of 25 canisters in the first year results in annual storage plus transfer doses at the post-exemption CAB that exceeds the 10 CFR 72.104 limit of 25 mrem/year. A review of Table 3.6.2 shows that a transfer of 25 canisters in the first year results in annual storage plus transfer doses at the EAB and at the railroad near Interstate Highway 1-5 that are less than the 10 CFR 72.104 limit of 25 mrem/year.

4.1 Conservatisms in Results 4.1.1 Conservatisms in existing TN ISFSI Storage dose calculation [Reference 5.2]

1. Each AHSM is assumed to be either loaded with design basis San Onofre Unit 1 or Units 2/3 fuel assemblies. For Unit 1, design basis fuel is considered to have a burnup of 45,000 MWD/MTU with 10 years of cooling and a design basis thimble plug . For Units 2/3 , design basis fuel is considered to have a burn up of 45 ,000 MWD/MTU with 5 years of cooling .

2. An extra loaded AHSM module is included in ISFSI Phases 3 and 4.

3. This calculation selects the dose results from Phases 3 and 4, which bounds the current configuration . At each detector, the higher value of the two phases is used .

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1-207-1-C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 28 of 29

4. No credit is taken for decay of source since the assumed loading dates (Phase 3 in 2011 and Phase 4 in 2014 to present) .

5. Calculation does not credit shielding by Holtec ISFSI.

6. Dose at the west 100-meter perimeter is taken from locations along the seawall that are within 100 meters from the ISFSI fence .

4.1.2 Conservatisms in Units 2/3 GTCC Storage dose calculation [Reference 5.4]

1. Calculation does not credit shielding by Holtec ISFSI.

2. Dose at the west 100-meter perimeter is taken from the seawall detector locations that are within 100 meters from the ISFSI fence .

4.1 .3 Conservatisms in Holtec ISFSI Storage and Transfer dose calculation

[Reference 5.6]

1. Calculation does not credit sh ielding by TN ISFSI.

2. Simplification in modeling soil level results in slightly conservative results .

3. The seawall is assumed to be 50% degraded resulting in higher transfer dose at the west side locations.

CALCULATION SHEET NECP No. 0820-75665-6 Cale No. SO1-207-1 -C116 REV 2 Subject MODIFIED CONTROL AREA BOUNDARY ISFSI DOSE CALCULATION Page 29 of 29 5.0 References 5.1 10 CFR 72 .104 "Criteria for radioactive materials in effluents and direct radiation from an ISFSI or MRS" 5.2 TN Calculation SCE-23-0508 , Revision 0, "San Onofre Independent Spent Fuel Storage Installation (ISFSI) Dose Rate Calculation," Tables 9-2 and 9-3, [VPL SO23-207-16-C95, Revision 1].

5.3 TN Calculation SCE-01.0506 , Revision 1, "Dose Rate Calculations for SONGS Unit-1 Greater Than Class C (GTCC) Waste Container," [VPL SO1-207 C 166, Revision 2].

5.4 TN Calculation 21933-0503, Revision 1, "SONGS Off-Site Dose Calculation, "

[VPL SO23-207-50-C0006, Revision 1].

5.5 NUREG-2215, "Standard Review Plan for Spent Fuel Dry Storage Systems and Facilities." [Note: Section 1OB of this document incorporates former ISG-13]

5.6 Holtec Report No. Hl-2177793, Revision 3, Table 4, [VPL 1814-AR171-C0058, Revision 0].

5.7 Memorandum for File, "Occupancy Factors at San Onofre Owner Controlled Area Boundaries," by Eric Goldin, October 1, 1991 .

5.8 Towill Survey 15907-127-CAB Exhibit [see Figure 1.2 in this ECN]. Note: This CAB Exhibit will be reflected (become "official") in the 10 CFR 72 .212 reports after NRC approval.

5.9 Calculation DCS-001 (including ECN DR761058), "TN ISFSI 10 CFR 72.212 Evaluation" .

ML22062B039

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