ML24136A284
| ML24136A284 | |
| Person / Time | |
|---|---|
| Site: | 07201041, South Texas |
| Issue date: | 05/15/2024 |
| From: | Georgeson C South Texas |
| To: | Office of Nuclear Material Safety and Safeguards, Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| NOC-AE-24004043, 35599080 | |
| Download: ML24136A284 (1) | |
Text
May 15, 2024 NOC-AE-24004043 10 CFR 72.7 STI: 35599080 ATTN: Document Control Desk Director, Division of Fuel Management Office of Nuclear Material Safety and Safeguards U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 South Texas Project Units 1 and 2 Docket Nos. 50-498; 50-499; 72-1041 Independent Spent Fuel Storage Installation Supplement to Request for Exemption from Various Part 72 Regulations Resulting from Fuel Basket Design Control Compliance (EPID: L-2024-LLE-0017)
References:
- 1) Letter, C.H. Georgeson (STP) to Document Control Desk (NRC); Request for Exemption from Various Part 72 Regulations Resulting from Fuel Basket Design Control Compliance; May 7, 2024; (NOC-AE-24004024)
- 2) Conversation Record; Clarification Call with STP and NRC on CBS exemption; May 9, 2024; (ML24135A028)
By Reference 1, STP Nuclear Operating Company (STPNOC) submitted an exemption request to load MPC-37 Continuous Basket Shim (CBS) canisters and shuffle HI-STORM overpacks with the affected MPC-37 CBS canisters that were loaded in 2022. By Reference 2, the NRC Staff and STPNOC held a call on May 9, 2024, for STPNOC to provide clarifying information regarding the submitted exemption request. This supplement provides STPNOCs written responses to the NRC Staffs questions from the call.
There are no commitments in this submittal.
If there are any questions regarding this submittal, please contact Chris Warren at (361) 972-7293 or me at (361) 972-7806.
C.H. Georgeson General Manager, Engineering
Attachment:
NRC Clarification Requests and STPNOC Responses
NOC-AE-24004043 Page 2 of 2
cc:
Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 1600 E. Lamar Boulevard Arlington, TX 76011-4511
Yen-Ju Chen Office of Nuclear Material Safety and Safeguards
Donald Habib Office of Nuclear Material Safety and Safeguards
NOC-AE-24004043 Attachment
Attachment
NRC Clarification Requests and STPNOC Responses
NOC-AE-24004043 Attachment Page 1 of 4
NRC Clarification Requests and STPNOC Responses
- 1. NRC Clarification Request: Clarify what exemptions that STP is requesting:
- a. Future loading of 2 canisters
STPNOC Response: STPNOC is requesting an exemption to load two MPC-37 Continuous Basket Shim (CBS) canisters in the 2025 Dry Cask Storage (DCS) campaign that are not in compliance with the 10 CFR 72.212 and 10 CFR 72.214 regulations identified in Reference 1.
- b. Shuffling already loaded canisters
STPNOC Response: STPNOC is requesting an exemption to relocate (i.e.
shuffle) 10 fuel-loaded Spent Fuel Storage Casks (SFSCs) that implemented the MPC-37 CBS design. SFSC is defined in Certificate of Compliance 1032, Appendix A, as the HI-STORM overpack and integral Multi-Purpose Canister (MPC). The purpose of the shuffle is to consolidate the fuel-loaded SFSCs on the Independent Spent Fuel Storage Installation (ISFSI) pad to ensure adequate space for staging empty SFSCs during the 2025 DCS campaign and minimize long-term damage to the ISFSI pad due to cask transporter use. An exemption is not needed to shuffle empty SFSCs.
- c. Continued storage of already loaded canisters
STPNOC Response: STPNOC is no longer requesting an exemption for continued storage of previously-loaded MPC-37 CBS canisters. As documented in Reference 2, the NRC will issue Non-Cited Violations for non-compliant canisters in accordance with the NRC Enforcement Policy. Restoration of compliance for the non-compliant canisters would occur following issuance of Certification of Compliance 1032, Amendment 7. Continued storage was evaluated to be the preferred action for protection of the environment as opposed to the alternative action of unloading spent fuel from the MPCs into the Spent Fuel Pool, as discussed in Reference 1.
- 2. NRC Clarification Request: Justification for requesting expedited approval by 7/8/2024.
- a. Future loading is in March 2025
STPNOC is now requesting approval of the exemption by July 18, 2024. If the exemption request is not approved by this date, STPNOC would need to purchase two new MPCs with the approved welded basket design to load in the 2025 DCS campaign. The vendor has confirmed an approximate delivery in April 2025 for two additional MPCs with the approved welded basket design to minimize delays to the 2025 DCS campaign scheduled to begin March 2025.
Delays in the 2025 DCS campaign would have cascading impacts to future new fuel receipt, refueling outages, and other enterprise projects.
- b. No information on planned shuffling dates
STPNOC Response: STPNOC is scheduled to perform SFSC shuffling activities in January 2025.
NOC-AE-24004043 Attachment Page 2 of 4
- 3. NRC Clarification Request: Need additional inf ormation on shuffling previously loaded canisters.
- a. Explain what is shuffling
STPNOC Response: Shuffling is a term used by STPNOC to describe the activity of relocating fuel-loaded SFSCs on an ISFSI pad. This activity is typically performed for two reasons:
- 1. Consolidate SFSCs into tighter groups, allowing more maneuverability of a cask transporter on the ISFSI pad and optimization of available space on the ISFSI pad.
- 2. Relocation of SFSCs can provide additional shielding to plant structures (warehouses, fabrication shops, etc.) by placing a SFSC with lower dose rates in front of a SFSC with higher dose rates.
STPNOC is planning shuffling to optimize available space on the ISFSI pad for cask transporter maneuverability and m inimizing long-term damage to the ISFSI pad from cask transporter use. There will be the secondary benefit of self-shielding by the casks. Figure 1 shows the current SFSC storage locations and Figure 2 shows a projected layout once shuffling activities are completed.
Figure 1 - Current STP ISFSI SFSC Storage Note: SFSC locations highlighted in red include the MPC-37 CBS variant with STP equipment ID numbers provided in Table 2 of Reference 1. SFSC locations highlighted in green include the MPC-37 welded basket variant.
NOC-AE-24004043 Attachment Page 3 of 4
Figure 2 - Post-Shuffle ISFSI SFSC Storage Note: SFSC locations highlighted in red include the MPC-37 CBS variant. The layout of the affected SFSCs is conceptual for illustrative purposes and may not reflect the final storage locations.
- b. Why it is safe to shuffle?
STPNOC Response: The Technical Justification and Environmental Considerations in the exemption request (Reference 1) are applied to shuffling SFSCs on the ISFSI pad. Specifically:
- 1. The SFSCs are transported using a single-failure proof cask transporter and lifting equipment, as described in Reference 1.
Use of this equipment precludes a cask tip-over event during transport activities.
- 2. The SFSCs remain within the ISFSI facility, which does not challenge the evaluated 10 CFR 72.104 dose rates at the Owner Controlled Area boundary.
- c. When and how many canisters are involved in the shuffling?
STPNOC Response: STPNOC is projecting to perform SFSC shuffling activities in January 2025 to relocate all 10 fuel-loaded SFCSs with the MPC-37 CBS variant.
- 4. NRC Clarification Request: Otherwise in the Public Interest
STPNOC asserts it is in the public interest to grant the requested exemption by July 18, 2024, due to the lead time for the DCS Vendor to source, fabricate, and deliver two additional MPC-37 canisters. As discussed in Reference 1, being able to load the two MPC-37 CBS canisters in 2025 will ensure adequate full core offload margin that is necessary for completing refueling outages, implementing enterprise projects, and sustained safe and efficient operation of the nuclear facilities. Performance of the SFSC shuffle is necessary to minimize long-term damage to the ISFSI pad, ensuring long-term safe storage of fuel-loaded SFSCs.
NOC-AE-24004043 Attachment Page 4 of 4
- 5. NRC Clarification Request: Consideration of Alternatives
STPNOC has evaluated the following alternatives to the exemption:
- a. Tracking NRC issuance of Certificate of Compliance 1032, Amendment 7
STPNOC has been tracking NRC issuance of Certificate of Compliance, Amendment 7 and understands the current schedule to issue the amendment in October 2024. However, significant public comments could result in delaying the issuance of the amendment as the comments are addressed. If this scenario is realized and the exemption request is not approved, STPNOC will be beyond the projected lead time for the DCS vendor to deliver two additional MPCs for the 2025 DCS campaign. This scenario presents a risk to the STP 2025 DCS campaign and the cascading effects to new fuel receipt, refueling outages and other enterprise projects. NRC approval of the exemption request would eliminate this risk to shuffling SFSCs and loading MPC-37 CBS canisters in 2025.
- b. Delaying loading of the affected MPC-37 CBS canisters beyond 2025
STPNOC has evaluated loading the affected MPC-37 CBS canisters beyond 2025. The next scheduled DCS campaign is in 2028 and is currently planned to be 16 casks instead of the typical 12 casks. This number could grow based on the results of a revised criticality analysis for the Unit 1 Spent Fuel Pool. This could result in an extended DCS campaign upwards of 18 casks, including the two MPC-37 CBS canisters. STPNOCs new fuel receipt and long-range outage schedule do not support an extended DCS campaign of this magnitude at STP.
- c. Procuring unused MPCs from another utility
STPNOC has evaluated the potential to procure empty MPCs from other utilities; however, STPs fuel assemblies are approximately 2 feet taller than other utilities that load the MPC-37 model, so procuring empty MPCs from other utilities is not an option.
References
- 1. Letter, C.H. Georgeson (STP) to Document Control Desk (NRC); Request for Exemption from Various Part 72 Regulations Resulting from Fuel Basket Design Control Compliance; May 7, 2024; (NOC-AE-24004024) (ML24128A157)
- 2. NRC Memorandum, Kristina Banovac (NRC) to Cinthya Roman (NRC); Summary of March 6, 2024, Public Meeting with Holtec International Inc. and the Holtec Users Group to Discuss the Path Forward for General Licensees Affected by the Continuous Basket Shims Basket Design Change, May 8, 2024; (ML24067A302)