ML19319B208

NRR E-mail Capture - Request for Additional Information Related to TMI-1 Request for Exemption from Portions of 10 CFR 50.47 and Part 50 Appendix E (L-2019-LLA-0216)

ML19319B208
Person / Time
Site:	Three Mile Island
Issue date:	11/15/2019
From:	Justin Poole NRC/NRR/DORL/LPL1
To:	Brady R, Holden L Exelon Generation Co
References
L-2019-LLA-0216
Download: ML19319B208 (4)

Text

From: Poole, Justin Sent: Friday, November 15, 2019 11:48 AM To: Holden, Leslie E.:(Exelon Nuclear); Brady, Robert R:(Exelon Nuclear)

Cc: Danna, James

Subject:

Request for Additional Information Related to TMI-1 Request for Exemption from Portions of 10 CFR 50.47 and Part 50 Appendix E (L-2019-LLA-0216)

Attachments: L-2019-LLE-0016 RAI.pdf Leslie/Bob, By letter dated July 1, 2019, Exelon Generation Company, LLC (Exelon, the licensee) submitted an exemption request (Agencywide Documents Access and Management Systems (ADAMS)

Accession No. ML19182A104), with corresponding exemptions from portions of 10 CFR 50.47 and 10 CFR Part 50, Appendix E, that would allow reducing emergency planning requirements for the permanently defueled condition at Three Mile Island Nuclear Station, Unit 1.

On November 5, 2019, the NRC staff sent Exelon the DRAFT RAIs to ensure that the questions are understandable, the regulatory basis is clear, there is no proprietary information contained in the RAI, and to determine if the information was previously docketed. On November 14, 2019, the NRC and Exelon held a clarifying call. During the call, Exelon requested a response date of 30 days from the date of the call. The NRC staff informed NextEra that this timeframe is acceptable. The attached is the final version of the RAIs. These RAIs will be put in ADAMS as a publicly available document.

Justin C. Poole Project Manager NRR/DORL/LPL I U.S. Nuclear Regulatory Commission (301)415-2048

Hearing Identifier: NRR_DRMA Email Number: 313 Mail Envelope Properties (BL0PR0901MB4388BDDFE3A32B4F2A31564D9D700)

Subject:

Request for Additional Information Related to TMI-1 Request for Exemption from Portions of 10 CFR 50.47 and Part 50 Appendix E (L-2019-LLA-0216)

Sent Date: 11/15/2019 11:47:44 AM Received Date: 11/15/2019 11:47:00 AM From: Poole, Justin Created By: Justin.Poole@nrc.gov Recipients:

"Danna, James" <James.Danna@nrc.gov>

Tracking Status: None "Holden, Leslie E.:(Exelon Nuclear)" <Leslie.Holden@exeloncorp.com>

Tracking Status: None "Brady, Robert R:(Exelon Nuclear)" <Robert.Brady@exeloncorp.com>

Tracking Status: None Post Office: BL0PR0901MB4388.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 1163 11/15/2019 11:47:00 AM L-2019-LLE-0016 RAI.pdf 89740 Options Priority: Normal Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

REQUEST FOR ADDITIONAL INFORMATION DEFUELED EMERGENCY PLAN EXEMPTION REQUEST EXELON GENERATION COMPANY, LLC THREE MILE ISLAND NUCLEAR STATION, UNIT 1 DOCKET NO. 50-289 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 (TMI-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 staffs 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 TMI-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 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.