ML23215A165

August 8, 2023 Presubmittal Meeting Presentation - Technical Specification 3.8.1 AC Sources - Operating Required Action B.4, 14-hour Completion Time (EPID: L?2023?LRM-0053)

ML23215A165
Person / Time
Site:	Comanche Peak
Issue date:	08/04/2023
From:	Dennis Galvin NRC/NRR/DORL/LPL4
To:
References
EPID L?2023?LRM-0053 TS 3.8.1
Download: ML23215A165 (1)

Text

Pre-Submittal Meeting Technical Specification 3.8.1 AC Sources

- Operating Required Action B.4, 14-hour completion time

Agenda

• Objective of the meeting

• Proposed Technical Specification (TS) change

• Justification for the TS change

• Reason for the TS change

• Risk Insights

• Open Discussion CPNPP Pre-Submittal Meeting

Objective of the Meeting

• To discuss a proposed License Amendment Request (LAR) to extend the completion time for TS 3.8.1 Required Action 4.B from 72-hours to 14-days with an APG available.

• The proposed LAR is based on deterministic requirements supplemented by risk insights.

CPNPP Pre-Submittal Meeting

Proposed TS Change

• Technical Specification (TS) 3.8.1 AC Sources - Operating requires two Diesel Generators (DGs) capable of supplying the onsite Class 1E power distribution subsystem(s) to be OPERABLE in MODEs 1 through 4.

• Condition B One DG Inoperable, Required Action B.4 Restore DG to OPERABLE status, has a completion time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or in accordance with the Risk Informed Completion Time Program.

• The Required Action B.4 Completion Time will be Modified by the addition of OR 14 days with (APG) Available.

• A new Required Action B.5 Ensure Availability of Alternate Power Generator (APG), will be added with a completion time of Once before entering the Required Action B.4, 14-day Completion Time AND Once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> thereafter.

CPNPP Pre-Submittal Meeting

Proposed TS Change

• A new Condition C (APG Required by Required Action B.4 Unavailable), will be added with a Note, Condition C. can only be entered once per Condition B. Entry.

• A new Required Action C (Restore Required (APG) to Available Status), will be added with Completion Time, 24 Hours AND Within 14 days of entering Condition B.

• The current Conditions C through I, will be renumbered to D through J.

• The new Condition C will be added to Condition G Required Action and associated Completion Time of Condition not met, with Required Actions and Completion times of; be in Mode 3 in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, AND be in Mode 5 in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.

CPNPP Pre-Submittal Meeting

Justification for the TS Change

• The change and has been developed using the guidelines established in NUREG-0800, Branch Technical Position 8-8, Onsite (Emergency Diesel Generators) and Offsite Power Sources Allowed Outage Time Extensions.

• This proposed change satisfies the requirement in NUREG-0800, BTP 8-8 to verify the availability of the APG prior to entering the extended 14-day CT, and after the initial verification that availability continue to be checked once every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> (i.e.,

once per shift).

• This proposed change satisfies the requirement in NUREG-0800, BTP 8-8 that if the APG becomes unavailable during the extended 14-day CT, it must be returned to an available status, or a shutdown will be commenced within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. This condition is only permitted once within any given extended 14-day CT.

CPNPP Pre-Submittal Meeting

Justification for the TS Change (continued)

• Consistent with BTP 8-8 planned entries into the 14-day completion time will have multiple actions taken:

• The APG will be ready to align to pre-determined 6.9 kV Class 1E bus.

• Limits on the fuel oil level will be established and maintained.

• Guarded Equipment postings and carries will be placed to control access to protected equipment.

• Control Room staff will review actions to align and start the APG.

• Operations will designate an operator to align and start the APG.

• Switchyard access will be limited such that offsite power sources are not challenged.

CPNPP Pre-Submittal Meeting

Reason for the TS Change (continued)

• Moving Diesel Generator maintenance from refueling outages to at-power operations provides more flexibility in outage scheduling while maintaining defense-in-depth throughout the outage.

• More focused maintenance can be accomplished during a longer maintenance window and therefore would improve maintenance efficiency.

• Risk from routine Diesel Generator maintenance would not be accumulated against the Risk Informed Completion Time (RICT) rolling 12-month incremental risk allowance, allowing more cumulative risk to address emergent issues.

CPNPP Pre-Submittal Meeting

Risk Insights

• In the PRA model, only the use of the APGs as a backup to the failure of the protected EDG is explicitly quantified.

• The unquantifiable aspect is the use of the APGs as a backup to either the protected EDG train or the out of service EDG train.

• Other Risk Management Actions are not quantified.

Unit 1 - Case IA (CT= 14 days)

Quantifiable Results Hazards Delta CDF ICCDP Delta LERF ICLERP (per year) ((CP) (per year) (CT)

Internal Events and 7.60E-07 7.60E-07 5.33E-08 5.33E-08 Internal Flooding Internal Fire 1.45E-06 1.45E-06 1.37E-07 1.37E-07 Total 2.21E-06 2.21E-06 1.90E-07 1.90E-07 CPNPP Pre-Submittal Meeting

Risk Insights

• Key driver is a fire in the protected train switchgear

• Normal Risk Management Actions are applied as part of the Configuration Risk Management Program to minimize potential fire initiators

• Operators are trained on proceduralized process to align the APGs to either train as necessary

• Typical Risk Management Actions considered for an EDG outage (not an all-inclusive list)

• Guarded Equipment Program

• Suspension of elective work on the AFW (all 3 trains), RHR, CCPs, CHS, SSW and CCW systems (and support systems) as well as the switchyard

• Operations briefings on the procedures for connecting the APG given a Loss of offsite power and failure of the protected EDG CPNPP Pre-Submittal Meeting

Conclusion

• The requested completion time for TS 3.8.1 Required Action 4.B extension from 72-hours to 14-days with an APG available meets the deterministic requirements for the extension.

CPNPP Pre-Submittal Meeting

Open Discussion Questions?

CPNPP Pre-Submittal Meeting