ML20244D570
| ML20244D570 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 04/12/1989 |
| From: | Hairston W ALABAMA POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 8904240008 | |
| Download: ML20244D570 (4) | |
Text
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Alabama Pow:r Company 40 Inverntss Center Parkway Post Office Box 1295 Birmingham, Alabama 35201 Telephone 205 868 5581 0
W. G. Hairston, Ill Senior Vice President Nuclear Operations AlabamaPOWer April 12, 1989 the southem electac system Docket Nos. 50-348 50-364 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk-Vashington, D. C.
20555 Gentlemen:
Joseph M. Farley Nuclear Plant - Units 1 and 2 Station Blackout on July 21, 1988 the NRC amended 10CFR Part 50 to include Section 50.63 regarding Station Blackout.
Section 50.63 requires that each light water-cooled nuclear power plant be able to withstand and recover'from a station blackout of a specified duration and that the plant be capable of maintaining core cooling and appropriate containment integrity for that specified duration.
Section 50.63 further requires that each licensee submit the following information:
A proposed station blackout duration including a justification for the selection based on the redundancy and reliability of the onsite emergency AC power sources, the expected frequency of loss of offsite power, and the probable time needed to restore offsite power; A description of the procedures that vill be implemented for station blackout events for the specified duration and recovery therefrom; and A list and proposed schedule for any modifications to equipment and associated procedures necessary for the specified blackout duration.
The NRC has issued Regulatory Guide 1.155, " Station Blackout", which describes a means acceptable to the NRC Staff for meeting the requirements of 10CFR50.63.
Regulatory Guide 1.155 states that the NRC Staff has determined that NUMARC 87-00, " Guidelines and Technical Bases for NUMARC Initiatives Addressing Station Blackout at Light Vater Reactors", provides guidance that is acceptable for meeting the requirements of 10CFR50.63. Alabama Power Company has evaluated Joseph H. Farley Nuclear Plant, Units 1 and 2, against the requirements of 10CFR50.63 using guidance from NUMARC 87-00 except where Regulatory Guide 1.155 takes precedence.
The results of this evaluation are detailed in the attachment.
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U. S. Nuclear Rrgulatory Commission April 12, 1989 ATTN: Document Control Desk Page 2 The modifications and. associated procedure changes identified in the attached evaluation will be completed within two years of receipt of notification of the regulatory assessment from the NRC or a
. justification will be provided for an alternate schedule.
If there are any questions, please advise.
Respectfully submitted, ALABAMA POVER COMPANY al.}. /64~ m:-
V. G. Hairston, III VGH,III/RGV:mV.456 Attachment cc:
Mr. S. D. Ebneter Mr. E. A. Reeves Mr..G. F. Maxwell l
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' A.~ -Preposxd Statien Bleckout Duration NOMARC 87-00, Section 3, was used to det' ermine a station blackout duration of four hours-for Farley Nuclear _ Plant, Units 1 and 2.
The.
following plant factors were identified in determining this durations-1)
The AC power design characteristic group is "P1" based ont a) The expected frequency.of grid-related loss of offsite power does not exceed once per twenty' years; b) The estimated frequency'of loss of offsite power due to
-extremely severe weather places Farley Nuclear Plant, Units 1 and 2, in extremely severe weather group three (3);
c) The estimated frequency of loss of offsite power due to-severe weather places Parley Nuclear Plant, Units 1 and 2, in severe weather group one (1);
- d) The offsite'pover system for Farley Nuclear. Plant, Units 1 and 2, is in-the I 1/2 group; e) The severe weather recovery factor does not affeet the AC power design characteristic group determination' based on Regulatory Guide 1.155, Tables 4 and 7.
2)
The_ emergency AC power configuration for Farley Nuclear Plant, Units 1 and 2, is group C since each Unit requires either train A or train B emergency power to operate safe shutdown equipment following a loss of offsite power.
3)
The target emergency diesel generator (EDG) reliability for Farley Nuclear Plant, Units 1 and 2, is 0.95 based on EDG reliability for the last 100 demands on each EDG model.
The Farley Nuclear Plant. technical specifications require the EDG surveillance frequency to be based on. reliability calculated in'accordance with Regulatory Guide 1.108, Revision 1, August 1977. Alabama Power Company vill calculate the EDG reliability in accordance with Regulatory Guide 1.108, Revision 1, for each EDG model at Farley Nuclear Plant. This methodology for calculating EDG reliability is conservative when compared to the methodology of NSAC-108 referenced in Regulatory Guide 1.155 and NUMARC 87-00 and is consistent with the existing technical specifications.
4)
An alternate AC (AAC) power source vill be utilized at Farley Nuclear Plant, Units 1 and 2, which meets the criteria specified in Appendix B to NUMARC 87-00.
The AAC power source is an existing emergency diesel generator which meets the assumptions in Section 2.3.1 of NUMARC 87-00.
The diesel generator vill be available within ten minutes of the onset of the station blackout event and has sufficient capacity and capability to operate systems necessary for coping with a station blackout for the required duration of four hours.
It is_noted that Class 1E battery capacity, compressed air and containment isolation need not be addressed since the AAC power source vill be available within ten minutes.
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Procedure Description l
Procedures for Farley Nuclear Plant, Units 1 and 2, are being reviewed and revised as necessary to address AC power restoration-4 guidelines and preparation for hurricane / tornado guidelines as referenced in NUMARC 87-00.
C.
P,roposed Modifications Modifications will be required to ensure that service water is available.to the alternate AC power source using the worst case assumptions for. station blackout.
In addition, modifications will be required to automatically shed unnecessary loads to ensure sufficient capacity is available for manual loading of the required station blackout loads. Procedures will also be revised to indicate proper operator actions in a station blackout event to ensure'that the AAC l
power source is properly loaded during a station blackout event.
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Condensate Inventory For Decay Heat Removal It has been determined from Section 7.2.1 of NUMARC 87-00 that 58,662 gallons of water are required for decay heat removal for four hours for each Unit at Farley Nuclear Plant. The minimum permissible condensate storage tank level per technical 3
specifications provides 150,000 gallons of water for each unit, i
which exceeds the required' quantity for a four hour coping duration.
2)
Effects of Loss of Ventilation l
The AAC power source provides power to the HVAC systems serving the emergency safeguards feature (ESP) room coolers and the control room which are the dominant areas of concern.
Therefore, the effects of loss of ventilation are not required to be assessed for Farley Nuclear Plant, Units 1 and 2.
3)
Reactor Coolant Inventory The AAC power source vill power the necessary make-up systems to maintain adequate reactor coolant system inventory to ensure that the core is cooled for the required coping duration of four hours.
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