ML14324A823

NRR E-mail Capture - Non-Acceptance with Opportunity to Supplement - Davis-Besse LAR to Revise EDG Minimum Voltage SRs (ME8746)

ML14324A823
Person / Time
Site:	Davis Besse
Issue date:	06/21/2012
From:	Michael Mahoney Plant Licensing Branch III
To:	Lashley P FirstEnergy Nuclear Operating Co
References
ME8746
Download: ML14324A823 (3)

Text

NRR-PMDAPEm Resource From: Mahoney, Michael Sent: Thursday, June 21, 2012 10:55 AM To: 'phlashley@firstenergycorp.com'

Subject:

Non-Acceptance with Opportunity to Supplement - Davis-Besse LAR to Revise EDG Minimum Voltage SRs (ME8746)

Phil, By letter dated May 23, 2012, (ADAMS Accession No. ML12144A383), FirstEnergy Nuclear Operating Company (FENOC) submitted a license amendment request (LAR) to revise the Technical Specifications (TS),

in Appendix A to Facility Operating License Numbers NPF-3 for the Davis-Besse Nuclear Power Station, Unit No. 1 (DBNPS). The LAR proposes revising TS 3.8.1, "AC Sources - Operating" to change the minimum voltage acceptance criterion for emergency diesel generator (EDG) surveillance testing in surveillance requirements 3.8.1.8 and 3.8.1.14 from greater than or equal to 4031 volts (V) to greater than or equal to 4070V.

We have determined that the information described below is necessary to make an assessment of the acceptability of the proposed amendment. Inform me of your availability to participate in a teleconference within 5 days of this communication.

The purpose of the teleconference is to ensure the scope of the required information is understood and to determine if the information can be submitted within the required supplement schedule (not greater than 13 working days).

Required Information:

1. Provide excerpts from calculation(s) that establish the limiting voltage at various safety busses for equipment operability.

2. Provide the minimum starting voltage for large motors and the voltage drop at the remote safety buses associated with starting large motors such as the Service Water System Pumps?

3. Assuming the EDG achieves a no load voltage level of 4070V for breaker closure, verify that the proposed steady state voltage of 3744V is adequate for satisfactory start and operation of safeguards equipment.

4. Verify that the minimum voltage observed during load sequencing or large motor starts will not adversely impact equipment that was running with EDG nominal voltage at 3744V.

5. The upper end of allowable voltage for steady state operation (4400V) is not changed. Verify that voltage spikes observed during full load rejection testing at given power factor and initial voltage of 4400V will not adversely impact the EDG or any other safety grade equipment.

6. The torque speed curves of induction motors are dependent on system frequency. Verify that DG loading is within the capabilities of the DG at the onset of an event when the pumps may be operating at run out conditions and during steady state conditions with the DG operating at the upper end of the allowable voltage and frequency.

7. According to UFSAR Section 8.3.1.1.3, four degraded voltage relays are set to monitor nominal bus voltage level. The degraded voltage relay setpoint is typically based on the minimum voltage required for equipment operability. Verify that the degraded voltage relays do not have to be reset (if actuated) during a loss off offsite power event when the EDG is required to supply plant loads.

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8. The LAR states that the minimum frequency of 58.8 Hz required by SR 3.8.1.8 and 3.8.1.14 is acceptable per Safety Guide 9, Selection of Diesel Generator Set Capacity for Standby Power Supplier, dated March 10, 1971. The frequency parameters discussed in Safety Guide 9, Section C, Regulatory Position, refer to transient frequency variation and recovery times during the EDG load sequencing process. Clarify if the proposed minimum frequency of 58.8 Hz is the minimum frequency required to be maintained when loading the EDG.

9. Provide details on how the minimum frequency of 58.8 Hz and steady state frequency values 59.5H z and 60.5Hz are used to determine safeguards equipment operational requirements during design basis accident calculations.

a) Provide details on performance capabilities of accident mitigation equipment (pumps, motors, valves, etc.) when the EDG is operating at the lower end of the allowable voltage and frequency bands during design basis events.

b) The LAR states Davis-Besse is in compliance with Safety Guide 9, Section C, EDG voltage and frequency tolerances during EDG load sequencing. Verify that motor operated valve performance is not adversely impacted (accident analyses) at the lower end of the TS allowable frequency coupled with the frequency/voltage variations allowed in Safety Guide 9.

Thanks Mike Michael Mahoney Davis-Besse, Perry and FENOC Fleet Project Manager, Licensing Branch III-2 U. S. Nuclear Regulatory Commission Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Phone: (301)415-3867 Email: Michael.Mahoney@NRC.GOV 2

Hearing Identifier: NRR_PMDA Email Number: 1704 Mail Envelope Properties (A41C2340DAB39B44AD0B9623285CB33365D3059D57)

Subject:

Non-Acceptance with Opportunity to Supplement - Davis-Besse LAR to Revise EDG Minimum Voltage SRs (ME8746)

Sent Date: 6/21/2012 10:55:02 AM Received Date: 6/21/2012 10:55:00 AM From: Mahoney, Michael Created By: Michael.Mahoney@nrc.gov Recipients:

"'phlashley@firstenergycorp.com'" <phlashley@firstenergycorp.com>

Tracking Status: None Post Office: HQCLSTR02.nrc.gov Files Size Date & Time MESSAGE 4629 6/21/2012 10:55:00 AM Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

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