ML20132G529
| ML20132G529 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 06/18/1985 |
| From: | Knighton G Office of Nuclear Reactor Regulation |
| To: | Carey J DUQUESNE LIGHT CO. |
| References | |
| GL-83-28, NUDOCS 8507190353 | |
| Download: ML20132G529 (6) | |
Text
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JUN 18 bos Docket No.:
50-412 Mr. John J. Carey Vice President, fluclear Duquasco I.ight Company Robinson Plaza Building, flo. 2, Suite 10 PA Route 60 Pittsburch, Pennsylvania 15205
Dear Hr. Carey:
SUBJECT:
REQUEST FOR ADDITIOf7L INFORMATION (RAI) REGARDING PREVENTIVE MAINTENANCE PROGP.Ali FOR REACTOR TRIP PDEAKERS/ MAINTENANCE AND TRENDING - BEAVER VALLEY, UNIT
- Enclosed please find RAI for the review of itens 4.1, 4.2.1 and 4.2.2 in Generic Letter 83-28. These items are also referred to as Reactor Trip Systen Peliability and Preventive Maintenance Progran for Reactor Trip Preakers/ Maintenance and Trer. ding.
Based on the review of your initial sutnittal, this RAI has been prepared.
Your pronpt response will be erPreciated.
Should you have any questions please contact the Project Manager, B. K.
Singh at (301) 492-8423.
Sincerely, f
George W. Knighton, Chief Licensing Branch No. 3 Division of Licensing
Enclosure:
As stated cc: See next page
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Beaver Valley Mr. John J. Carey Vice President, Nuclear Duquesne Light Company Robinson Plaza Building, No. 2, Suite 110 PA Route 60 Pittsburgh, Pennsylvania 15205 Gerald Charnoff, Esq.
Mr. R. E. Martin, Manager Engineering Jay E. Silberg, Eso.
Beaver Valley Two Pro.iect Shaw, Pittman, Potts & Trowbridge Duquesne Light Company 1800 M Street, N.W.
Robinson Plaza Buildina No. 2, Suite 110 Washington, DC 20036 PA Route 60 Pittsburgh, Pennsylvania 15205 Mr. C. W. Ewing, Quality Assurance Zori Ferkin Manager Assistant Counsel Quality Assurance Department Governor Energy Council Duquense Light Company
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Harrisburg, PA 15105 1625 N. Front Street P. O. Box 186 Shippingport, Pennsylvania 15077 Mr. John J. Carey Vice President, Nuclear Duquense Light Company Director, Pennsylvania Emergency P. O. Box 4 Management Agency Shippingport, Pennsylvania 15077 Room B-151 Transportation & Safety Building Harrisburg, Pennsylvania 17120 Mr. T. J. Lex Mr. Thomas Gerusky Westinghouse Electric Corporation Bureau of Radiation Protection Power Systems PA Department of Environmental P. O. Box 355 Resources Pittsburgh, Pennsylvania 15230 P. O. Box 2063 Harrisburg, Pennsylvania 17120 Mr. P. RaySircar Stone & Webster Engineering Corporation BVPS-2 Records Management Supervisor P. O. Box 2325 Duquesne Light Company Boston, Massachusetts 02107 Post Office Box 4 Shippingport, Pennsylvania 15077 Mr. Glenn Walton U. S. NRC John A. Lee, Esq.
P. O. 181 Duauesne Light Company Shippingport, Pennsylvania 15077 1 0xford Centre 301 Grant Street Mr. Thomas E. Murley, Regional Admin.
Pittsburgh, Pennsylvania 15279 U. S. NRC, Region I 631 Park Avenue King of Prussia, Pennsylvania 15229
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' Mr. E. F. Kurtz, Jr., Manager Regulatory Affairs Beaver Valley Two Pro.iect Duquense Light Company
' Robinson Plaza Bufdling No. 2 Suite #210 PA Route 60 Pittsburgh, Pennsylvania 15205 t
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Enclosure BEAVER VALLEY POWER STATION, UNIT 2 REQUEST FOR ADDITIONAL INFORMATION CONCERNING POST-FIRE SAFE SHUTDOWN AUXILIARY SYSTEMS BRANCH 1.
A recent plant inspection at another facility revealed that for a fire in the control room, isolation transfer switches for certain hat shutdown systems / components had to be switched to the alternate or isolated posi-tion prior to damage occurring to these circuits.
If this were not accomplished in time, fuses would have to be replaced in order to make safe shutdown system / component operable. This situation existed because the transfer switches did not place new/ redundant fuses into the control power circuit, but left the existing (assumed blown) set of fuses in the circuit.
For most of the transfer switches, the situation did not cause a problem since the desired effect after isolation was the deenergization of power.
In other instances where the system / component had to be operable or where operation might be required to override a spurious actuation (such as a motor operated valve) replacement of fuses would be required if blown.
Although the present isolation switches at Beaver Valley Unit 2 do isolate the required equipment or component from the control room, it has not been demonstrated that it is unnecessary to replace fuses in order to place the equipment / component in the desired mode of operation or position.
In order for us to conduct a review to determine if fuse replacement is necessary for the operation of a safety system after a control room fire, please pro-vide the following:
a.
The results of your review of electrical design drawings for the existing isolation transfer switches to determine where and if this situation exists.
b.
If the Beaver Valley Unit 2 design necessitates the changing of fuses to achieve and maintain hot shutdown after a control room fire, provide modifications to existing switches and/or install new isolation switches where necessary to provide redundant fusing such that a blown fuse will not require replacement to achieve and maintain hot shutdown.
2.
We have a concern regarding the potential for multi-high impedance faults in AC power circuits which could result in the loss of power to safe shut-down equipment. Figure 1 contains a sketch of circuit designs which could result in the loss of needed power to safe shutdown equipment. As can be seen in Figure 1, redundant divisions of safe shutdown cables are properly separated in accordance with Appendix R criteria. However, a fire in fire area A would result in loss of Division A safe shutdown equipment and cause damage to nonsafe shutdown cables associated with the Division A bus.
Further, the individual fault current resulting from the fire damage in the nonsafe shutdown cables may not be enough to trip the individual breakers
,d -
2 (B, and 8 ), but the sum of the faults may be sufficient to trip the main 7
breaker, 8 ).
If this were to occur, the Division B bus and the corres-2 ponding redundant Division B safe shutdown would be lost. You must show that multi-high impedance faults in AC power circuits resulting from a single fire cannot result in the loss of function of any safety-related system as outlined above.
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