ML20236R895
| ML20236R895 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 11/18/1987 |
| From: | Gucwa L GEORGIA POWER CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| SL-3651, NUDOCS 8711240090 | |
| Download: ML20236R895 (6) | |
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X Georgia Power Companyi 333 Piedmont Avenue i
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c Atlanta, Georgis 30308 -
- Titiphone 404 526-6526 -
- Malling Adbr'ess::
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. Fbst Office Box 4545 J Atlanta, Georgia 30302 h
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. Georgia Power L T. Gucwa the southern electnc system
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. Manager Nuclear Safety and Licensing.
SL-3651 0624m X7GJ17-V200 November 18, 1987 fU.S.NuclearRegulatoryCommission
- ATTN: _ Document' Control Desk 4
Washington..D.C. '20555 L LANT V0GTLE - UNITS 1, 2 i
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'NRC DOCKETS _50-424, 50-425 OPERATING LICENSE NPF-68, CONSTRUCTION PERMIT CPPR-109 ANTICIPATED TRANSIENTS WITHOUT SCRAM MODIFICATIONS
' Gentlemen:
. Bye. letter dated July 30. 1987, Georgia Power Company submitted a description of the ' ATHS Mitigating Systems Actuation Circuitry (AMSAC) 1 system.being installed at P1 ant Vogtle Units 1 and 2.
In a September 30, 1987. conference ' call,- NRC staff members requested additional information 1
' concerning AMSAC.
The enclosure. to this letter provides the ' requested
'information.-
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Pleasel contact this office if you.have any' questions.
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Sincerely,
& qe-L. T. Gucwa 1
JH/1m'
Enclosure:
'AMSAC Additional Information c:- (see next page)'
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.Dr.'J. N.' Grace,. Regional Administrator iTA Msi M. A.' Miller, Licensing. Project Manager,.NRR (2 copies) g 4,Mr.;iJ. F. Rogge;. Senior l Resident Inspector-Operations, Vogtle
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Georgia Power b ENCLOSURE PLANT V0GTLE UNITS 1, 2 NRC DOCKETS 50-424, 50-425 OPERATING LICENSE NPF-68, CONSTRUCTION PERMIT CPPR-109 AMSAC ADDITIONAL INFORMATION y
STAFF RE00EST Confirm that. the criteria of Generic Letter 85-06, " Quality Assurance i
Requirements for ATHS Equipment That is Not Safety Related" are met by the Vogtle AMSAC.
RESPONSE
The quality assurance practices applied to non-safety related AMSAC equipment comply with Generic Letter 85-06.
STAFF REOUEST Confirm that the Vogtle AMSAC design complies with Revision 1 of WCAP-10858, "ASMAC Generic Design Package" and provide the basis for the Vogtle timer settings.
RESPONSE
The Vogtle AMSAC design complies with Revision 1 of HCAP-10858.
Vogtle uses the low feedwater flow logic depicted in Figure 2-3.
The variable time' delay on energizing for Vogtle will be set such that the time delay as a function of power will fall near the middle of the acceptable range depicted in Figure 2-4.
Figure 2-4 was determined on a generic basis and is applicable to the Vogtle units. The upper curve of Figure 2-4 ensures that AMSAC will be initiated in time to prevent overpressurization of the lRCS and to minimize RCS voiding.
The lower curve of Figure 2-4 ensures that enough time is allowed for an RPS signal to be actuated prior to AMSAC actuation.
This has been a design objective of the HOG AMSAC effort.
The Vogtle variable time delay is depicted on the enclosed figure.
Because the AMSAC actuation signal can be delayed up to 230 seconds for Vogtle, the time delay on de-energizing the C-20 permissive must be set such that the actuation logic will still be met under these conditions.
The time delay on de-energizing the C-20 permissive will therefore be nominally set at 260 seconds for Vogtle.
After turbine load drops below the C-20 setpoint and the 260 second time delay expires, AMSAC is disarmed.
0624m E-1 11/18/87 SL-3651 l
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Georgia Power m.
ENCLOSURE (Continued)
AMSAC ADDITIONAL INFORMATION STAFF'REOUEST Indicate the frequency at which a complete system test will be performed and explain testing capability at power.
RESPONSE
A complete test of the AMSAC system, including the AMSAC outputs through to the final actuation devices, will be performed during each refueling
. outage.
Hith the plant at power, the system can be tested with the AMSAC outputs bypassed.
At-power testing capability consists of a series of overlapping tests as described in our July 30, 1987 submittal.
These tests verify analog channel accuracy, setpoint (bistable trip) accuracy, coincidence logic operation including operation and accuracy of all timers, and continuity through the output relay coils.
STAFF RE00EST Provide clarification of how mitigative action, once initiated, will go to completion.
RESPONSE
The AMSAC system is actuated by low main feedwater flow.
Following a
. variable time delay,_ signals to initiate auxiliary feedwater flow and trip the main turbine are generated, provided the proper permissives and setpoints are still met.
The AMSAC system does not utilize " latch in" relays.
Once the AFH pumps receive a start signal from AMSAC, they will remain on line until plant conditions allow the operator to secure the pumps.
The motor driven AFH pumps will trip if an overcurrent condition exists or a sequencer load shed signal is received.
The turbine driven AFH pump has electrical and mechanical overspeed trips.
Once a main turbine trip is initiated there are no automatic or anual actions which can prevent it from going to completion.
Following completion of mitigative action, deliberate operator action is required to reset the AFH and turbine trip systems.
The AFH system is reset for standby readiness by:
G624m E-2 11/18/87 SL-3651 l
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k Georgia Power u ENCLOSURE (Continued AMSAC ADDITIONAL INFORMATION 1.
clearing _the start signal, 2.
aligning valves in the proper configuration, and l
3.
placing automatic valve and pump handswitches in AUTO.
A main turbine trip is reset during startup by:
1.
resetting the lockout relays and relay targets, 2.
checking that the CLOSE VALVES turbine speed set light is lit and that turbine load is set at zero, 3.
observing that-the main stop valves, control
- valves, and intercept valves remain closed when the turbine is reset, 4.
depressing and holding the turbine RESET pushbutton until both
.the mechanical trip and the electrical trip lights change from TRIPPED to RESET, 5.
verifying that the intermediate stop valves stroke open, and 6.
resetting the ~ first hit status lights by depressing both FIRST HIT RESET' buttons.
When turbine load reaches the C-20 setpoint, the AMS.AC system will be armed.
STAFF RE0 VEST Identify the manufacturer and model number of the AMSAC output isolation devices.
Either verify that these devices have been approved by NRC in accordance with Appendix A of the AMSAC SER or provide a schedule for submittal of information required by Appendix A.
RESPONSE
The Vogtle AMSAC uses Struthers Dunn Model 219 " plug-in" type relays as output isolation devices.
Westinghouse is currently qualifying this relay.
Information to demonstrate compliance with Appendix A of the AMSAC-SER will be submitted by May 1,1988.
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