ML20004G092
| ML20004G092 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 06/16/1981 |
| From: | Ash R BALTIMORE GAS & ELECTRIC CO. |
| To: | Clark R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8106290168 | |
| Download: ML20004G092 (2) | |
Text
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S ALTIMORE GAS AND ELECTRIC CHARLES CENTER. P.O. BOX 1475 BALTIMORE, MARYLAND 21203 ELECTRIC ENGINEERING OEPARTMENT Q
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Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission d
bg@Ih Washington, D. C.
20555
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Mr. Robert A. Clark, Chief 3G
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Operating Reactors Branch #3 9#
Division of Licensing M
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Subject:
Calvert Cliffs Nuclear Power Plant Units Nos.1 % 2; Dockets Nos. 50-317 & 50-318
'TRC Recuirenents for Auxiliary Feedvater System Peference: Ltr from R. A. Clark to A. E. Lundvall, Issuance of Amendments Nos. Sh & 37, dated 8 t'ay 1981 Gentlemen:
In the safety evaluation contained in the above referenced letter the following statement is made for the F7aluation of GL3 (page 16):
" Evaluation-GL3 - The licensee resnonded by letter dated Leeenber 13, 1979, that the mator onerated auxiliary feedvater nunn turbine steam supuly valves renresent the only feature of the systi that depends on alternating current power. BG&E has installed tile circuitrv to automatically initiate afb'S flow by starting both steam-driven pumps. In order to satisf*/ the long-term recuirement on AC independence the existing steam sunnly AC motor-operated valves vill be replaced with AC controlled fail-ouen air-operated valves. Therefore, loss of AC will cause these steam sunnly valves to fail open starting the turbine driven AFWS pumps. We find the response to this recommendation, with the pending modifications, eceptable."
j i% have determined that the use of solenoid valves which are constantly energized leads to maintenance problems. The valves must be j
replaced much more frequently than those which are only energized when the function is required. We feel that constantly energized solenoid valves l
are not as reliable for the above reason.
In light of the above infor=ation, ve have decided to use DC controlled air-operated valves. ne valves vould be held shut by air, which is sunnlied by a normally de-energized solenoid valve. Energization of the solenoid would vent the diachrags and cause the valve to oten.
P P00RORG E M106290
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R. A. Clark Page 2 June 16, 1981 We feel this arrangement is accentable for the following reasons :
(1) The system is single-failure proof. There is one valve Der steam generator and only one is required to open to adequately supoly the pumns.
(2) The solenoid valves are povered from 125 volt de off the batteries.
-(3) The valve can be onened by manually venting the diaphragm or one can totally avoid operating the valve by onening the full flow bynass instead.
In a phone discussion with your E. J. Sullivan and E. L. Conner on 15 June 1981, it van determined that this change does not alter the intent of the evaluation of GL3 contained in the above referenced License Amendment and the item remains resolved.
Should you have any questions, feel free to contact us.
Very truly yours,
/
R. F. Ash Chief Nuclear Engineer cc: J. A. Biddison, Esquire G. F. Trowbridge, Esquire Messrs. E. L. Conner, Jr. - NRC J. C. Ventura - Bechtel P. W. Kruse - CE e
P00R ORENAL