ML19344C115

Response to Request for Additional Information (RAI) Regarding Request for Exemptions from Portions of 10 CFR 50.47 and 10 CFR Part 50, Appendix E

ML19344C115
Person / Time
Site:	Three Mile Island
Issue date:	12/10/2019
From:	Gallagher M Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
EPID L-2019-LLA-0216, TMl-19-166
Download: ML19344C115 (6)

Text

Michael P. Gallagher Exelon Nuclear Exelon Generation . Vice President License Renewal and Decomm1ss1on1ng 200 Exelon Way Kennett Square, PA 19348 610 765 5958 Office 610 765 5658 Fax www.exeloncorp.com michaelp.gallagher@exeloncorp.com 10 CFR 50.12 10 CFR 50.47 10 CFR 50, Appendix E TMl-19-166 December 10, 2019 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Three Mile Island Nuclear Station, Unit 1 Renewed Facility Operating License No. DPR-50 NRC Docket No. 50-289 Three Mile Island Nuclear Station, Unit 2 Possession Only License No. DPR-73 NRC Docket No. 50-320

Subject:

Response to Request for Additional Information (RAI) Regarding Request for Exemptions from Portions of 10 CFR 50.47 and 10 CFR Part 50, Appendix E

References:

1) Letter from Michael P. Gallagher, (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission - "Request for Exemption from Portions of 10 CFR 50.47 and 10 CFR 50, Appendix E," dated July 1, 2019(ML19182A104)

2) Letter from J. Bradley Fewell (Exelon Generation Company, LLC) to U.S.

Nuclear Regulatory Commission, "Certification of Permanent Cessation of Power Operations for Three Mile Island Nuclear Station, Unit 1," dated June 20, 2017 (Accession No. ML17171A151)

3) Letter from Michael P. Gallagher (Exelon Generation Company, LLC),

"Certification of Permanent Removal of Fuel from the Reactor Vessel for Three Mile Island Nuclear Station, Unit 1," dated September 26, 2019 (Accession No. ML19269E480)

4) U.S. Nuclear Regulatory Commission Electronic Mail Request to Leslie E. Holden and Robert R. Brady - "DRAFT RAJ for EP and EAL Amendment/Exemption," dated November 5, 2019

U.S. Nuclear Regulatory Commission TMI Request for EP Exemption RAI Response Docket Nos. 50-289 and 50-320 December 10, 2019 Page 2

5) U.S. Nuclear Regulatory Commission Electronic Mail Request to Leslie E. Holden and Robert R. Brady - "Request for Additional Information Related to TMl-1 Request for Exemption from Portions of 10 CFR 50.47 and Part 50 Appendix E (L-2019-LLA-0216)," dated November 15, 2019 (ML19319B208)

By letter dated July 1, 2019 (Reference 1), Exelon Generation Company, LLC (Exelon) requested an exemption pursuant to the requirements of 10 CFR 50.12 from specific emergency planning requirements in 10 CFR 50.47and10 CFR Part 50, Appendix E forthe Three Mile Island Nuclear Station (TMI) based on the permanent cessation of power operations and removal of fuel from the reactor vessel on TMI, Unit 1 (TMl-1 ). Exelon has docketed the certifications for permanent cessation of operations and permanent removal of fuel from the reactor vessel (References 2 and 3), therefore in accordance with 10 CFR 50.82(a) the 10 CFR Part 50 license for TMl-1 no longer authorizes operation of the reactor or emplacement or retention of fuel into the reactor vessel.

Subsequently, in an electronic mail request dated November 5, 2019 (Reference 4) the U.S.

Nuclear Regulatory Commission (NRC) issued draft Requests for Additional Information (RAls) indicating that it had reviewed the information submitted in the Reference 1 letter and that additional clarifying information was needed to support its continued review. The draft RAI in Reference 4 was further discussed during teleconferences between Exelon and NRC representatives held on November 14, 2019. As a result of the discussions, it was determined that no modifications to the draft RAI was needed and the NRC subsequently issued formal RAI on November 15, 2019 (Reference 5) and requested a response 30 days from the clarification call on November 14, 2019.

Exelon's responses to the NRC's RAls are provided in Attachment to this letter.

Exelon has reviewed the information supporting a finding of No Significant Hazards Consideration and the Environmental Consideration provided to the NRC in Reference 1. The additional information provided in this submittal does not affect the previously stated bases in Reference 1 for concluding that the proposed exemption does not involve a significant hazards consideration.

In addition, the information provided in this submittal does not affect the bases for concluding that neither an environmental impact statement nor an environmental assessment needs to be prepared in connection with the proposed exemption.

There are no regulatory commitments contained in this submittal.

U.S. Nuclear Regulatory Commission TMI Request for EP Exemption RAI Response Docket Nos. 50-289 and 50-320 December 10, 2019 Page 3 If you have any questions concerning this submittal, please contact Leslie Holden at (630) 657-2524.

Respectfully,

~{? I Michael P. Gallagher Vice President, License Renewal & Decommissioning Exelon Generation Company, LLC

Attachment:

Response to Request for Additional Information Regarding Request for Exemptions from Portions of 10 CFR 50.47 and 10 CFR Part 50, Appendix E cc: Regional Administrator - NRC Region I NRC Project Manager, NRR - TMl-1 Director, Bureau of Radiation Protection - PA Department of Environmental Resources

ATTACHMENT Response to Request for Additional Information Regarding Request for Exemptions from Portions of 10 CFR 50.47 and 10 CFR Part 50, Appendix E

Attachment TMI Request for EP Exemption RAI Response Docket Nos. 50-289 and 50-320 Page A-1 of A-2 NRC REQUEST FOR ADDITIONAL INFORMATION (RAil 10 CFR 50 provides regulatory requirements for emergency planning for operating reactors to ensure protection of the health and safety of the public. By letter dated July 1, 2019, pursuant to 10 CFR 50.12 "Specific Exemptions," Exelon requested exemptions from certain emergency planning regulations in 10 CFR 50.47 and 10 CFR Part 50, Appendix E, for the permanently shut down Three Mile Island Nuclear Station, Unit 1 (TMl-1).

NUREG-1738, "Technical Study of Spent Fuel Pool Accident Risk at Decommissioning Nuclear Power Plants," (ADAMS Accession No. ML010430066) describes a modeling approach of a typical decommissioning plant with design assumptions and industry commitments. The NRC staff's analyses and conclusions apply to decommissioning facilities with spent fuel pools (SFPs) that meet the design and operational characteristics assumed in the risk analysis. These characteristics are identified in the study as industry decommissioning commitments (IDCs) and staff decommissioning assumptions (SDAs). In the exemption request, Exelon evaluated the IDCs and SDAs contained in NUREG-1738 and submitted Tables 4 and 5 to identify how the TMl-1 SFP meets or compares with each of these IDCs and SDAs.

A characteristic of concern documented in IDCs and SDAs is the potential for loss of SFP inventory and uncovering of fuel. The following is related to mitigation of draining or inventory loss:

SDA #4 states, "Licensee determines that there are no drain paths in the SFP that could lower the pool level (by draining, suction, or pumping) more than 15 feet below the normal pool operating level and that licensee must initiate recovery using offsite sources."

The TMl-1 exemption request provides comparison (Section 5.5 and Tables 4 and 5 of ) to the NUREG-1738 IDCs and the SDAs. The configuration of SFPs in the TMI Fuel Handling Building consists of two connected pools, Pool A (1494 SFP storage locations) and Pool B (496 SFP storage locations). A cask loading pit is located within Pool B.

The TMl-1 SFP is contained in the Fuel Handling Building and is connected to the Fuel Transfer Canal via two fuel transfer tubes. As indicated in Section 9.4.6, "Leakage Considerations" of Updated Final Safety Analysis Report (FSAR), a locked closed gate valve (on the Fuel Handling Building side) and blind flange (on the Reactor Building side) are used to isolate the fuel transfer tubes when not actively performing refueling. The transfer tube passes through the primary containment wall and through an exterior wall of the fuel handling building.

The licensee discussion in the exemption request related to leakage prevention devices are limited to locked closed gate valves and blank flanges on the reactor building side. As discussed in the associated license amendment request, also submitted on July 1, 2019, the top of active fuel is approximated at 320 ft. Licensee documentation (Drawing IE-154-02-009, Revision 9, General Arrangement Fuel Handling Building) shows the transfer tubes penetrating the pool wall below the top of stored fuel (Transfer Tube CL at EL 314'-6" and pool floor at 305'-0").

Since the fuel transfer tube penetration has the capability of inadvertent draining below top of fuel, provide additional details regarding administrative control of the pool-side gate valves and

Attachment TMI Request for EP Exemption RAI Response Docket Nos. 50-289 and 50-320 Page A-2 of A-2 describe any design features that could prevent or mitigate the consequences of opening of the gate valve when the reactor refueling cavity is not flooded.

EXELON'S RESPONSE TO RAI TMl-1 has two transfer tubes that connect the Spent Fuel Pool (SFP) to the Fuel Transfer Canal in the Reactor Building. The design provides double isolation of each transfer tube to prevent inadvertent draining of the Spent Fuel Pool. On the SFP side, each transfer tube is isolated with a locked closed manual gate valve (FH-V-1A/B). On the Reactor Building side the transfer tube is isolated with a blank flange. Since 50.82(a)(2) no longer permits operation of TMl-1 or emplacement of fuel in the reactor vessel, there is no longer a need to transfer fuel between the reactor and the SFP, therefore there is no need to manipulate FH-V-1A/B or remove the blank flange.

FH-V-1A/B will remain locked closed under administrative control per OP-M-108-103, "Locked Equipment Program." The blank flange on the Reactor Building side of the fuel transfer tube, is bolted in place and not readily removable.