L-12-270, Withdrawal of License Amendment Request to Revise Emergency Diesel Generator Minimum Voltage Surveillance Requirements, and Add Figure Axis Labels
| ML12199A056 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 07/16/2012 |
| From: | Allen B FirstEnergy Nuclear Operating Co |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| L-12-270, TAC ME8746 | |
| Download: ML12199A056 (4) | |
Text
FENOC FirstEnergy Nuclear Operating Company Barry S. Allen Vice President - Nuclear July 16, 2012 L-12-270 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
Subject:
Davis-Besse Nuclear Power Station Docket No. 50-346, License No. NPF-3 5501 North State Route 2 Oak Harbor, Ohio 43449 419-321-7676 Fax: 419-321-7582 Withdrawal of License Amendment Request To Revise Emergency Diesel Generator Minimum Voltage Surveillance Requirements, and Add Figure Axis Labels (T AC No. ME8746)
By letter dated May 23, 2012 (Accession Number ML12144A383), FirstEnergy Nuclear Operating Company (FENOC) submitted a Davis-Besse Nuclear Power Station license amendment request to address a nonconservative technical specification related to a diesel generator output breaker voltage permissive. This license amendment request would have revised Technical Specification 3.8.1, "AC Sources - Operating" by changing the minimum voltage acceptance criterion for emergency diesel generator surveillance testing in surveillance requirements 3.8.1.8 and 3.8.1.14 from greater than or equal to 4031 volts to greater than or equal to 4070 volts. The license amendment request would have also incorporated axis labels on Technical Specification Figure 3.7.18-1, "Maximum Allowable Steam Generator Level." FirstEnergy Nuclear Operating Company hereby withdraws this license amendment request.
The NRC staff notified FENOC by an e-mail dated June 21, 2012 that additional information, identified in the attachment to this letter, is necessary to make an assessment of the acceptability of the proposed amendment. The information request was discussed during a telephone conference between FENOC and the NRC staff on June 28, 2012. Some of the requested information went beyond the scope of the current license amendment request as well as the current licensing basis and is related to an identified industry issue that is being addressed through the owner's group.
Specifically, WCAP-17308-NP, Revision 0, "Treatment of Diesel Generator (DG)
Technical Specification Frequency and Voltage Tolerances," was submitted for NRC review and approval on May 1, 2012. Because some of the expanded scope information cannot be provided in the requested time frame, FENOC is withdrawing the proposed license amendment.
Davis-Besse Nuclear Power Station L-12-270 Page 2 There are no regulatory commitments contained in this letter. If there are any questions, or if additional information is required, please contact Mr. Phil H. Lashley, Supervisor - Fleet Licensing, at 330-315-6808.
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Attachment:
Information Requested By NRC Staff cc:
NRC Region III Administrator NRC Project Manager NRC Resident Inspector Executive Director, Ohio Emergency Management Agency, State of Ohio (NRC Liaison)
Utility Radiological Safety Board
Attachment L-12-270 Information Requested By NRC Staff Page 1 of 2 The following Information was requested by the NRC staff.
- 1. Provide excerpts from calculation(s) that establish the limiting voltage at various safety buses 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 emergency diesel generator (EDG) achieves a no load voltage level of 4070 volts (V) 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 diesel generator loading is within the capabilities of the diesel generator at the onset of an event when the pumps may be operating at run out conditions and during steady state conditions with the diesel generator operating at the upper end of the allowable voltage and frequency.
- 7. According to Updated Final Safety Analysis Report 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.
- 8. The license amendment request states that the minimum frequency of greater than or equal to 58.8 hertz required by surveillance requirements 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 greater than or equal to 58.8 hertz is the minimum frequency required to be maintained when loading the EDG.
Attachment L-12-270 Page 2 of 2
- 9. Provide details on how the minimum frequency of greater than or equal to 58.8 hertz and steady state frequency values greater than or equal to 59.5 hertz and less than or equal to 60.5 hertz 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, and so forth) when the EDG is operating at the lower end of the allowable voltage and frequency bands during design basis events.
b) The license amendment request 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 Technical Specification allowable frequency coupled with the frequency/voltage variations allowed in Safety Guide 9.