ML20213A935

Request for Additional Information Review of License Amendment Request to Revise Technical Specifications to Adopt Risk Informed Completion Times

ML20213A935
Person / Time
Site:	Nine Mile Point
Issue date:	07/30/2020
From:	Marshall M Plant Licensing Branch 1
To:	Bryan Hanson Exelon Nuclear
Marhsall M, NRR/DORL/LPL, 415-2871
References
EPID L-2019-LLA-0234
Download: ML20213A935 (3)

Text

From: Marshall, Michael To: [Licensee] Ron Reynolds (Exelon)

Cc: Danna, James

Subject:

NINE MILE POINT NUCLEAR STATION, UNIT 2 - REQUEST FOR ADDITONAL INFORMATION RE: REVIEW OF LICENSE AMENDMENT REQUEST TO REVISE TECHNICAL SPECIFICATIONS TO ADOPT RISK INFORMED COMPLETION TIMES (EPID L-2019-LLA-0234)

Date: Thursday, July 30, 2020 1:48:00 PM Hello Ron, By letter dated October 31, 2019 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML19304B653), Exelon Generation Company, LLC (Exelon, the licensee) requested that the U.S. Nuclear Regulatory Commission (NRC) amend the Technical Specifications, Appendix A of Renewed Facility Operating License No. NPF-69 for Nine Mile Point Nuclear Station, Unit 2. Exelons proposed license amendment request would revise technical specification requirements to permit the use of risk informed completion times for actions to be taken when limiting conditions for operation are not met. The proposed changes are based on Technical Specifications Task Force Traveler 505, Revision 2, Provide Risk Informed Extended Completion Times - RITSTF Initiative 4b, dated July 2, 2018 (ADAMS Accession No. ML18269A041).

The NRC staff has reviewed the information provided in the license amendment request and has determined that additional information is needed to complete its review. Below is the NRC staffs requests for additional information (RAIs). The RAIs were discussed with you on July 30, 2020, and it was agreed that Exelons response would be provided within 30 days from the date of this email.

The RAIs listed below are not a complete listing of the additional information needed to complete the NRC staffs review. Additional RAIs will be provided in separate correspondence.

RAIs

RAI 1

Section 50.36(c) of 10 CFR requires TS to contain limiting conditions of operation (LCO) that describe the lowest functional capability of equipment required for safe operation of a plant. In Table E1-1 of Enclosure 1 of the LAR, the licensee lists each LCO to which the RICT Program is proposed to be applied and the design success criteria (DSC) for the LCO. In section 1 of Enclosure 1, the licensee stated that the DSC is a summary of the success criteria from the design basis analyses.

The plants DSC are derived from the design basis analysis of the plant, as documented in the updated safety analysis report (USAR) and should include a minimum set of required equipment that has the capacity and capability to safely shut down the reactor in case of an accident and maintain it in a safe condition. NMP2 USAR, Section 8.1.4 states, in part:

The emergency ac [alternating current] power system is divided into three physically separate and electrically independent divisions designated Divisions I, II, and III. Any two out of these three divisions [have] the

capacity and capability to safely shut down the reactor in case of a LOCA

[loss of coolant accident] or any other DBA [design basis accident].

In Table E1-1 of Enclosure 1 of the LAR, the licensee stated that the DSC for TS LCO 3.8.1, Condition B, are one non-HPCS (high pressure core spray) emergency diesel generator (EDG). However, in the LAR, the DSC for TS LCO 3.8.1.B are one non-HPCS EDG while the USAR states that two divisions of the AC power system are required to safely shut down the reactor.

Please explain this apparent discrepancy DSC in Table E1-1 of Enclosure 1 of the LAR and the Nine Mile Point USAR. Additionally, describe any effect the discrepancy may have on the PRA success criteria for TS LCO 3.8.1.B.

RAI 2

Section 50.36(c) of 10 CFR requires TS to contain limiting conditions of operation (LCO) that describe the lowest functional capability of equipment required for safe operation of a plant. In Table E1-1 of Enclosure 1 of the LAR, the DSC for TS LCO 3.8.1.C (two required offsite circuits inoperable) is one offsite source. The NRC staff notes that the programs condition description for TS 3.8.1.C is, [t]wo offsite circuits inoperable. If both offsite circuits are inoperable, one offsite source, as listed in the DSC, cannot provide the necessary power to shutdown the reactor and maintain it in safe condition. Therefore, it is not clear how one offsite circuit can be the DSC for TS 3.8.1.C during the RICT program entry.

Please explain this apparent discrepancy in Table E1-1 of Enclosure 1 of the LAR.

Additionally, describe any effect the discrepancy may have on the PRA success criteria for TS LCO 3.8.1.C.

RAI 3

As part of its evaluation, the NRC staff reviews the proposed risk management action (RMA) examples for reasonable assurance that the RMAs are considered to monitor and control risk and to ensure adequate defense-in-depth. Enclosure 12 of the LAR describes the RMAs examples for TS 3.8.1.A, TS 3.8.1.B, TS 3.8.1.D, and TS 3.8.4.A. However, the LAR does not include the RMA examples for TS 3.8.1.C, TS 3.8.7.A, TS 3.8.8.A, TS 3.8.8.B, and TS 3.8.8.C.

Please provide RMA examples for TS 3.8.1.C, TS 3.8.7.A, TS 3.8.8.A, TS 3.8.8.B and TS 3.8.8.C.

RAI 4

In the LAR, the licensee stated that the proposed amendment is consistent with TSTF-505, Revision 2. In Section 2.3 of Attachment 1 of the LAR, the licensee lists the variations from

TSTF-505, Revision 2. The TSTF contain model LCOs. Section 50.36(c) of 10 CFR requires TS to contain LCOs that describe the lowest functional capability of equipment required for safe operation of a plant.

For the required action of Restore one [required] offsite circuit to OPERABLE status for the condition Two [required] offsite circuits inoperable, the completion time is 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

In the LAR the completion time is 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> from discovery of both HPCS and Low Pressure Core Spray (LPCS) Systems with no offsite power. The NRC staff notes that this difference appears to be a variation. The apparent variation between TSTF-505 and the NMP2 proposal is that the NMP2 TS requires restoration of one offsite circuit within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> from discovery of both HPCS and LPCS systems without offsite power. The LAR does not address the apparent variation. Please provide a discussion of the difference and how it is implemented into the RICT program.

RAI 5

Section 50.36(c) of 10 CFR requires TS to contain limiting conditions of operation that describe the lowest functional capability of equipment required for safe operation of a plant. TSTF-505, Revision 2 (ADAMS Accession No. ML18183A493), does not allow for TS loss of function conditions (i.e., those conditions that represent a loss of a specified safety function or inoperability of all required trains of a system required to be operable) in the risk informed completion time program.

There appears to be an error in the logical connector for the note for LCO 3.3.5.1, ECCS -

Instrumentation, Action B.3.1 in that the note should apply only to the 24-hour completion time. Therefore, the OR should be indented instead of what is currently proposed (where the OR would apply to both the 12-hour and 24-hour completion times). If the OR applies to the 12-hour completion time, based on the design success criteria provided in the license amendment request, it appears that this LCO action may constitute a loss of function.

a) Clarify whether the OR applies to both the 12-hour and 24-hour completion times or just the 24-hour completion time.

b) If the OR does apply to the 12-hour completion time, provide the technical basis for why the action does not constitute a loss of function.

Best Regards, Michael L. Marshall, Jr., Senior Project Manager Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-410