ML20154G705
| ML20154G705 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 03/03/1986 |
| From: | Reinaldo Rodriguez SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Miraglia F Office of Nuclear Reactor Regulation |
| References | |
| RJR-86-83, TAC-64359, NUDOCS 8603100080 | |
| Download: ML20154G705 (4) | |
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,SMU-SACRAMENTO MUNICIPAL UTILITY DISTRICT ? 62o1 S Street. RO. Box 1583o. Sacramento CA 958521830.(916) 452-3211 AN ELECTRIC SYST EM SERVING THE HEART OF CAllFORNI/,
RJR 86-83 March 3,1986 DIRECTOR OF NUCLEAR REACTOR REGULATION ATTENTION FRANK J MIRAGLIA JR DIRECTOR PWR-B DIVISION US NUCLEAR REGULATORY COMMISSION WASHINGTON DC 20555 DOCKET 50-312 RANCHO SECO NUCLEAR GENERATING STATION UNIT NUMBER 1 EMERGENCY FEEDWATER INITIATION AND CONTROL (EFIC) CYCLE 8 SC0pE
References:
1.
R. J. Rodriguez to F. J. Miraglia letter dated 01/17/86 (RJR 86-27) 2.
R. J. Rodriguez to J. F. Stolz letter dated 04/28/83 A summary of the Cycle 8 Refueling Outage scope of EFIC was provided in the above Reference 1.
In an effort to further clarify the EFIC scope, a more detailed functional description is being provided as follows:
EFIC initiates Auxiliary Feedwater ( AFW); i.e., it will start both AFW pumps and positions AFW valves as necessary to feed the steam generators. This is independent of ICS which will no longer control AFW, EFIC automatically controls AFW flow to reach and maintain the proper steam generator level. The rate of level increase is automatically controlled when necessary as well as the level height depending on reactor coolant pumps operating or not operating (natural circulation).
EFIC detects secondary system breaks and isolates MFW and AFW to the affected steam generator.
EFIC monitors steam pressure and controls the atmospheric dump valves (ADV) if pressure exceeds a setpoint.
It also allows for safety grade steam pressure control of cooldown to cold shutdown conditions.
Backup N2 pressure will be added to the MFW/AFW control valves to ensure closure of the MFW valves and control of AFW valves for two (2) hours after loss of offsite power and therefore loss of normal air supply.
An additional parallel and redundant set of AFW valves is D.C. powered from a non-interruptable Class I source.
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v FRANK J MIRAGLIA March 3, 1986 EFIC controls for the ADV's and AFW flow control valves will be provided at the remote shutdown panel to allow control independent from the control room..
The conditions which cause EFIC to initiate AFW are:
low level in either steam generator loss of all 4 reactor coolant pumps low pressure in either steam generator loss of MFW (Flux /MFW flow anticipatory signal from RPS)
SFAS ECCS actuation (SFAS sends signal to EFIC)
The accelerated schedule for implementation of EFIC has necessitated some alteration of scope for Cycle 8 as compared to the scope described in the District's submittal of AFW upgrade details (see Reference 2).
Additionally, as mentioned in our submittal (Reference 2) some details of EFIC design have been altered in response to operating experience at other plants and our own efforts to advance the overall concept.
The significant changes are sumerized below:
Changes necessary for fuel Cycle 8 (only) to accomodate resource and/or equipmc7t lead time limitations:
1)
AFW flow control will be through a three valve per SG arrangement.
One control valve with a motor operated isolation valve in series will be paralleled by a single air operated control valve (see Attachment #1).
This necessitates changing the position of valves FV-20527 and FV-20528 to be normally closed.
2)
The MFW overfill logic will be functional.
However, the setpoint for isolation of MFW will be set to the maximum possible value of 619" in the steam generator.
This will allow data gathering to determine an appropriate setpoint at a later time.
3)
The redundant MFW isolation valves HV-20515 and HV-20516 will not have their motor operators until Cycle 9.
l 4)
For the EFIC AFW initiate there will be no automatic closure of the Main Steam cross-tie isolation valve HV-20565 until Cycle 9.
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5)
Reactor power versus MFW flow ($/MFW flow) Reactor Protection System 1
trip will be used as an anticipatory trip to start AFW through EFIC, but will not replace, for this cycle, the existing loss of MFW
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Anticipatory Reactor Trip.
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v FRANK J MIRAGLIA March 3, 1986 l
l Significant permanent changes to AFW upgrade design as compared to the status of the design described in Reference 2 follows:
A)
/FW pump P-319 will be actuated by EFIC channel A, and will continue to be connected to an emergency electrical bus powered by the existing "A" diesel generator.
Likewise AFW pump P-318 will be actuated by EFIC channel B, using it's turbine driver. The turbine steam admission valve will continue to be powered from a "B"
- train, battery backed, D.C. bus.
l B)
The use of time delay circuits in the initiate logic will be used to l
minimize spurious actuations.
C)
The shutdown bypass permissive signal has been altered to allow bypass when either steam generator secondary pressure is below 725 psig.
This simplifies operator action during a tube rupture scenario.
D)
Position indication of manual valves in the AFW flow path is not to be provided since each is locked in its safety position during plant operation.
If there are any questions concerning the EFIC Cycle 8 scope, please contact Mr. Jerry Delezenski (916) 452-3211 extension 4909, at Rancho Seco.
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R. J. RODRIGUEZ ASSISTANT GENERAL MANAGER, NUCLEAR Attachments
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