ML18050A025
| ML18050A025 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 02/19/2018 |
| From: | David Helker Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML18050A025 (2) | |
Text
200 Exelon Way Kennett Square, PA 19348 www.exeloncorp.com 10 CFR 50.90 February 19, 2018 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Limerick Generating Station, Units 1 and 2 Renewed Facility Operating License Nos. NPF-39 and NPF-85 NRC Docket Nos. 50-352 and 50-353
Subject:
Request for Implementation Date Extension Application to Revise Technical Specifications to Adopt TSTF-542, "Reactor Pressure Vessel Water Inventory Control," Revision 2
Reference:
Letter from James Barstow (Exelon Generation Company, LLC) to U.S.
Nuclear Regulatory Commission, "Application to Revise Technical Specifications to Adopt TSTF-542, 'Reactor Pressure Vessel Water Inventory Control,' Revision 2," dated July 19, 2017 (ADAMS Accession No. ML17200D096).
By letter dated July 19, 2017 (ADAMS Accession No. ML17200D096) (Reference), Exelon Generation Company, LLC (Exelon), requested approval to adopt Technical Specifications Task Force (TSTF) Traveler TSTF-542, Reactor Pressure Vessel Water Inventory Control, Revision 2, which changes the Technical Specifications (TSs) for Limerick Generating Station (LGS), Units 1 and 2.
The referenced letter requested approval of the proposed amendment by February 28, 2018 with a 90-day implementation period. However, based on the discussion that follows, Exelon anticipates that the proposed amendments, once approved, will be implemented on both units no later than startup from the Spring 2019 Unit 2 refueling outage.
While working through the requirements for implementation of the proposed amendment, the station identified a potential impact on the calculation of the Drain Time due to the removal of snubbers for testing in accordance with the Snubber Program. The definition of Drain Time in the proposed amendment specifies that the limiting drain rate is the larger of the drain rate through a single penetration flow path with the highest flow rate, or the sum of the drain rates through multiple penetration flow paths susceptible to a common mode failure (e.g., seismic event). The inclusion of a penetration flow path in the calculation of Drain Time is dependent upon whether the penetration flow path remains seismically qualified once a snubber is removed for testing purposes. The definition of Drain Time does allow for exclusion of those penetration flow paths where the capability of either automatic or manual isolation of the penetration exists. Therefore, this issue only applies to when the snubber is supporting portions of piping that are unisolable. For this population of snubbers, performance of a seismic analysis to determine whether the affected portion of the piping remains seismically qualified once the snubber is removed is required. As a result, additional time is necessary prior to implementation of the proposed
U.S. Nuclear Regulatory Commission Request for Implementation Date Extension Application to Revise TS to Adopt TSTF-542 Docket Nos. 50-352 and 50-353 February 19, 2018 Page 2 amendment to perform the applicable seismic analyses, or determine an acceptable alternative for implementing the proposed amendment.
Accordingly, Exelon requests that the proposed amendments, once approved, be implemented on both units no later than startup from the Spring 2019 Unit 2 refueling outage.
Exelon has reviewed the information supporting a finding of no significant hazards consideration, and the environmental consideration, that were previously provided to the NRC in Attachment 1 of the Reference 1 letter. Exelon has concluded that the information provided in this letter does not affect the bases for concluding that the proposed license amendment does not involve a significant hazards consideration under the standards set forth in 10 CFR 50.92. In addition, Exelon has concluded that the information in this letter 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 amendment.
There are no regulatory commitments in this letter.
In accordance with 10 CFR 50.91, "Notice for public comment; State consultation,"
paragraph (b), Exelon is notifying the Commonwealth of Pennsylvania by transmitting a copy of this letter to the designated State Official.
If you have any questions or require additional information, please contact Glenn Stewart at 610-765-5529.
I declare under penalty of perjury that the foregoing is true and correct. Executed on the 191h day of February 2018.
Respectfully, David P. Helker Manager, Licensing and Regulatory Affairs Exelon Generation Company, LLC cc:
Regional Administrator - NRC Region I NRC Senior Resident Inspector - Limerick Generating Station NRC Project Manager, NRR - Limerick Generating Station Director, Bureau of Radiation Protection - Pennsylvania Department of Environmental Protection