ML20125A511
| ML20125A511 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 06/04/1985 |
| From: | Lundvall A BALTIMORE GAS & ELECTRIC CO. |
| To: | John Miller Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8506110091 | |
| Download: ML20125A511 (3) | |
Text
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BALTIM O RE GAS AND ELECTRIC l
CHARLES CENTER.P. O. BOX 1475. BALTIMORE, MARYLAND 21203 ARTHUR E. LUNDVALL, JR.
l VICE PREsiotre?
$UPPLY Director of Nuclear Reactor Regulation Attention: Mr. J. R. Miller, Chief Operating Reactors Branch //3 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20535
Subject:
Calvert Cliffs Nuclear Power Plant Units Nos.1 & 2; Dockets Nos. 50-317 and 50-318 Post-LOCA Status of Reactor Coolant Pumps Reference NRC letter from 3. R. Miller to A. E. Lundvall, Jr. (BG&E),
dated April 23,1985 Gentlemen:
The following responds to your request for additional information regarding the proposed trip-two/ leave-two guidelines for post-LOCA operation of the reactor coolant pumps:
- 1. Does any containment isolation signal result in the termination of systems essential for continued operation of the reactor coolant pumps? If so, identify the signals and systems affected.
Respons,e_:
Cooling water for the reactor coolant pump seals, which is supplied by the Component Cooling Water System (CCW), is interrupted by a Containment isolation Signal (CIS).
A CIS is initiated by a two-out-of-four containment pressure sensor channel trip or manually from the control room.
- 2. If essential water services are terminated, provide a description of the operator guidelines, training, and procedures in place (or to be implemented) which assure that these services are restored in a timely manner to prevent seal damage or failure, once a non-LOCA situation has been confirmed.
Response
In the context of the RCP trip-two/ leave-two strategy, the operator trips the J
remaining two pumps if he is unable to maintain tN RCPs within operating limits. Calvert Cliffs emergency operating procedures remind the operator that CIS isolates CCW to the RCPs and instruct him to stop the pumps if CCW cannot be restored within ten minutes. This is consistent with the generic emergency 0506110091 950604 yDR ADOCK 050 y
Mr. 3. R, Miller June 4,1985 u:
procedure guidelines (CEN-152, Rev. 2) developed by Combustion Engineering for the CE Owners Group.
- 3. Provide confirmation, including the technical basis, that containment isolation with continued RCP operation will not lead to seal or pump failure.
Response
As discussed in the response to Question 2, operator instructions in the EOPs preclude a situation where the RCPs would be operated outside their operating limits. However, in the highly unlikely event that the operator falls to follow RCP. operating instructions, ignores the associated alarms and indicators, and maintains - RCP operation outside of the operating limits (e.g., without seal cooling), it should be realized that the-se limits were developed with the intent of being conservative with respect to seat reliability and performance. In addition, operating experience and the results of. a thirty-minute loss of seal cooling water -
test with the pump running substattlate the position that RCPs can operate without loss of seal function and without damage to the pumps themselves for time periods significantly in excess of the time periods defined in plant specific RCP opersting limits.
- 4. Since RCP trip will be required for LO'3A events, assurance must be provided that RC? trip, when required, will occur. To address this concern,' provide the following information:
(a) Identify the components required to trip the' RCPs. Include relays, power supplies and breakers. Address reliability and alternate trip methods.
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(b) If necessary, as a result of the location of any critical component, include t-the effects of adverse containment. conditions on RCP trip reliability.
Describe the basis for the adverse containment parameters selected.
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Response
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The components required to manually trip th'e RCP motors consist of a control L
switch, a 125-volt de power supply with associated fuses, and a 13 kV breaker with associated. trip coll. With the exception of the 125-volt dc power supply, none of this equipment is safety-related. All of this equipment is located in rooms which will be mild environments after an accident (control room, cable
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spreading room and switchgear room).
The 125-volt dc power supply is continuously monitored and abnormal conditions are alarmed in the control room. The 13 kV trip coil condition is also continuously displayed in the control room.
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Mr. 3. R. Miller June 4,1985 e
An alternate manual RCP trip which requires no power is avalfable at the breaker should the normal trip method described above not be available. The breaker is located in the switchgear room, which is a short distance from the control room.
I If you have any further questions, please do not hesitate to contact us.
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Very truly yours, 1->$3 AEL/BSM/vf I
cc: D. A. Brune, Esq.
G. F. Trowbridge, Esq.
Mr. D. H. Jaffe, NRC Mr. T. Foley, NRC l
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