ML20149L773
| ML20149L773 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 11/13/1996 |
| From: | Buckley B NRC (Affiliation Not Assigned) |
| To: | Ohanlon J VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| References | |
| TAC-M93415, TAC-M93416, NUDOCS 9611180069 | |
| Download: ML20149L773 (4) | |
Text
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Mr. J. P. O'Hanicn November 13, 1996 S;nior Vice Pr:sident - Nuclear Virginia Electric and Power Company 5000 Dominion Blvd.
Glen Allen, Virginia 23060
SUBJECT:
NORTH ANNA POWER STATION, UNITS 1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION CONCERNING EMERGENCY DIESEL i
GENERATOR ALLOWED OUTAGE TIME (TAC NOS. M93415 AND M93416)
Dear Mr. O'Hanlon:
In order to continue our evaluation of the above subject material, we find that it is necessary for you to respond to our request for additional information delineated in the Enclosure.
Sincerely, (Original Signed By)
Bart C. Buckley, Sr. Project Manager Project Directorate 11-1 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation 1
Docket Nos. 50-338 and 50-339
Enclosure:
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9611100069 961113 DR ADOCK 050 8
4 Mr. J. P. O'Hanlon North Anna Power Station Virginia Electric & Power Company Units 1 and 2 1
CC*
Mr. William C. Porter, Jr.
Regional Administrator, Region II County Administrator U.S. Nuclear Regulatory Commission Louisa County 101 Marietta Street, N.W.,
P.O. Box 160 Suite 2900 Louisa, Virginia 23093 Atlanta, Georgia 30323 Michael W. Maupin, Esquire Mr. W. R. Matthews, Manager Hunton and Williams North Anna Power Station Riverfront Plaza, East Tower P. O. Box 402 951 E. Byrd Street Mineral, Virginia 23117 Richmond, Virginia 23219 Mr. Al Belisle Dr. W. T. Lough U.S. Nuclear Regulatory Commission Virginia State Corporation 101 Marietta Street N. W. Suite 2900 Commission Atlanta, Georgia 30323-0199 Division of Energy Regulation P. O. Box 1197 Mr. David Christian, Manager
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Richmond, Virginia 23209 Surry Power Station Virginia Electric and Power Company Old Dominion Electric Cooperative 5570 Hog Island Road 4201 Dominion Blvd.
Surry, Virginia 23883 Glen Allen, Virginia 23060 Mr. M. L. Bowling, Manager 1
Nuclear Licensing & Operations Support Virginia Electric and Power Company Innsbrook Technical Center 5000 Dominion Blvd.
Glen Allen, Virginia 23060 Office of the Attorney General Commonwealth of Virginia
{
900 East Main Street Richmond, Virginia 23219 Senior Resident Inspector North Anna Power Station U.S. Nuclear Regulatory Commission 1024 Haley Drive Mineral, Virginia 23117 Robert B. Strobe, M.D., M.P.H.
State Health Commissioner Office of the Commissioner 4
Virginia Department of Health P.O. Box 2448 Richmond, Virginia 23218 5
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l ENCLOSURE i
Reauest for Additional Information 2
on the Ilorth Anna 1/2 Ann 11 cation for Technical Specifications Chance l
on EDG Allowed Outaae Time fA0T) Extension l
1 1.
Proposed Technical Specification 3.8.1.1 Action b (Limiting Condition of
)
Operation.with one emergency diesel generator (EDG) inoperable) is unacceptable. This action statement must be rewritten such that the requested 14-day allowed outage time is always applicable when an EDG is inoperable for whatever reason - not just once every 18 months when an l
EDG is in special maintenance. Also, this action statement must be conditioned upon the Alternate AC Source (AAC) being operable and "connectable" (breakers required for alignment to inoperable EDG's bus are operable, control power is available, etc.). Also, if the AAC is not operable, allowed outage time is limited to the current 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
i 2.
Proposed Technical Specification 3.8.1.1.b.2 states that the provisions of Specification 3.0.4 are not applicable. This is unacceptable to the j
staff. The licensee should remove this statement from the proposed Technical Specification.
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3.
The licensee should provide the actual out-of-service time needed to perform the preplanned EDG maintenance.
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4.
Recently the staff has become concerned, due to the inadequate design at another power plant, about the adequacy of the de voltage supply to the l
AAC. Specifically, the scenario of concern starts with the loss of offsite power and the loading of the EDG(s).
If the battery charger for the de supply to the AAC is not powered from an EDG-powered bus and the associated battery does not have adequate capacity, the availability of the AAC source is questionable should all ac sources be subsequently lost.
In light of this scenario, discuss the details of the power sources to the battery charger associated with the AAC source and the i
capacity of the charger and its associated battery.
5.
By letter dated April 12, 1996, the NRC requested additional information for review of your proposed changes to the North Anna Technical Specifications (TS). This request included a discussion on the three-tier approach the NRC staff expects licensees to utilize in proposing 1
risk-based modifications. Tier one involves determination of the change in operational risk. Tier two involves assurance.that risk-significant plant equipment outage configurations will not occur while the plant is subject to the Limiting Condition for Operation (LCO) for the proposed modification. The third tier assures that, before performing maintenance activities including removal of any equipment from service, the licensee performs a thorough assessment of the overall impact of the activity on safety functions of related TS activities. During the September 25, 1996, meeting between NRC staff and your staff, discussions involved how the three tiers are satisfied at North Anna.
The following questions reflect our discussion of these issues.
Tier 2 1.
Please submit a copy of procedure 1-MOP 6.90 that lists combinations of equipment that cannot be removed from service simultaneously.
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' a Tier 3 2.
Please submit a copy of the configuration risk management matrix discussed in the meeting and please discuss the probabilistic risk i
assessment basis of the matrix.
In your explanation of the basis of the matrix, please explain how the elements of the matrix are determined and categorized.
3.
How do you assess the resulting overall impact on safety functions when equipment that is not in the matrix is removed from service?
4.
Please also explain and submit a copy of the procedural program in which the configuration risk management matrix is imbedded.
5.
Are there currently plans to acquire a safety monitor as a more accurate method of enhancing configuration risk management? If so, when do you plan to implement the safety monitor, how do you plan to maintain the monitor, and who will be trained?
If not, describe how you assess the risk-based significance of taking or having a component taken out of service.
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