ML19256G110
| ML19256G110 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 12/18/1979 |
| From: | Peoples D COMMONWEALTH EDISON CO. |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0578, RTR-NUREG-578 NUDOCS 7912270464 | |
| Download: ML19256G110 (9) | |
Text
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Commonwealth Edison One First Nathnal Plaza, Chicago, ill.nois y
Addre'ss Rep:y to: Post Othce Box 767 Chicago, Illinois 60690 December 18, 1979 2
Mr. Darrell G. Eisenhut, Acting Director Division of Operating Reactors U. S. Nuclear Regulatory Commission Washingt:n, D.
C.
20555
Subject:
Zion Station Units 1 and 2 Additional Response to NRC Requirements for Auxiliary Feedwater Systems NRC Docket Nos. 50-295 and 50-304 References (a) :
September 18, 1979 letter from D. G.
Eisenhut to C.
Reed (b) :
October 19, 1979 letter from D.
L. Peoples to D.
G.
Eisenhut (c) :
December 14, 1979 letter from D.
L.
Peoples to D. G.
Eisenhut
Dear Mr. Eisenhut:
Reference (a) requested Commonwealth Edison Company to respond to NRC requirements for auxiliary feedwater systems at Zion Station.
Commonwealth Edison's response to this request was contained in Reference (b).
Subsequent discussions with members of your Staff indicated that some of Commonwealth Edison's responses in Reference (b) needed additional clarification, expansion and revision to more clearly meet the Staff's recommended positions.
Reference (c) provided additional information with regard to NRC Lessons Learned Recommendations 2.1.7a and 2.1.7b, " Auto-Initiation of Auxiliary Feedwater" and " Auxiliary Feed Flow Indication" The enclosed supplementary response should be incorporated into Reference (b), Commonwealth Edison's October 19, 1979 letter on Auxiliary Feedwater System requirements.
1644 I91 7912270fdf f
1 Commonwealth Edison NRC Docket Nos. 50-295/304 Mr. Darrell G. Eisenhut December 18, 1979 One (1) signed original and thirty-nine (39) copies of this transmittal are provided for your use.
Very truly yours, 2
(,( 1/
D.
L. Peoples Director of Nuclear Licensing WFN: rap Enclosure 1644 192 i
1 I
Enclosure A.
Supplementary Response to Attachment 1 of Reference (b) 1.
Replace Commonwealth Edison Response to GS-1 with:
2 Commonwealth Edison will propose a modification to the Zion Technical Specifications to limit the time to 7 days that one AFW system pump and its associated flow train and essential instrumentation can remain inoperable.
The time frame considered will maintain consistency with limiting conditions for operation imposed upon engineered safeguards equipment with similar redundancy.
The proposed technical specifications will be submitted by January 1, 1980.
2.
Replace Commonwealth Edison Response to GS-2 with:
Commonwealth Edison will incorporate a monthly verification of the locked open valve status of the AFW system into the surveillance requirements of Lne Zion Technical Specifications.
This proposal will be submitted by January 1, 1980.
3.
Supplement Commonwealth Edison Response to GS-3 with:
As noted in a November 14, 1979 letter from D.
L.
Peoples to D. G. Eisenhut, Commonwealth Edison estimated that the requested information of Enclosure 2 to Reference.
(a) would be available for submittal to the NRC Staff by March 21, 1980.
5.
Replace the Second Paragraph of Commonwealth Edison
~
Response to GS-5 with :
Therefore, until design changes are incorporated, Commonwealth Edison will establish by January 1, 1980 an emergency procedure to provide for turbine driven AFN pump operation as described in NRC Recommendation GS-5 of Reference (a),
i.e.
in an on-off mode in the event of the loss of all alternating current.
In order for the turbine driven AR1 pump to operate for at least two hours independent of any AC power source, it is necessary to modify the cooling water supply to the i
bearing coolers for both the feed pump and turbine drive.
~
The proposed modification will consist of providing a new and independent water supply line to these coolers.
This water supply line will originate from the turbine driven l
1644 193
.2 -
feedpump lst stage discharge port and terminate downstream of solenoid valve 1SVSW132 and upstream of line 1SW239-3/4".
This 1" water supply line will include a flow orifice assembly cnd pressure relief valve in order to regulate flow to 15gpm and maximum of 150 psig.
Solenoid valve 1SVSW132 will be deleted and the original service water supply to the coolers will be " capped off".
This design change will also include 2
a modification to'the bearing cooler return lines.
These return lines will be cambined in a common header and will be routed to the recirculating return line to the con-densate storage tank.
Refer to Figure 1 which contains a preliminary sketch as well as flow diagrams M-22 and M-34.
An engineering evaluation of this proposed modification "is being finalized and the modification will be implemented by May 1, 1980.
6.
Supplement Commonwealth Edison Response to GS-6 with:
More specifically, plant operating procedures require that upon startup the following actions be taken to verify AEW flow from the Condensate Storage Tank (CST) to the steam generators with AFW system valves in their normal alicnment and at design flow.
a)
The AFW system valve line up (from the CST to the steam generators) must be checked by an operator and then verified by management, prior to leaving cold shutdown.
b)
The Operating Surveillance, PT-7, must be performed on the two Motor Driven Pump AFW systems prior to leaving cold shutdown.
This surveillance provides for a flow check at design flow to the steam generators.
~~ c) ~ The normal flow path for AFW is used on startup for maintaining steam generator levels.
d)
The Operating Surveillance, PT-7, must also be performed on the Turbine Driven AFN Pump when steam is available.
e)
When main feedwater flow is established and AFW is to be removed from operation, each AFW pump system is left aligned to deliver design flow to each steam generator.
The above steps confirm that AR1 flow from the CST to the steam generators is delivered at design flow and that the system is in normal alignment.
The flow check will be incorporated into the existing technical spe^ification framework for AFW and submitted by January 1, 1960.
1644 194
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7.
Supplement Commonwealth Edison Response to GS-7 with:
Reference (c), a December 14, 1979 letter from D. L. Peoples to D. G. Eisenhut providin, an additional response to NRC Lessons Learned Recommendations 2.1.7a and 2.1.7b.
2 B.
Supplementary Response to Attachment 2 of Reference (b) 1.
Supplement Commonwealth Edison Response with:
Commonwealth Edison intends to upgrade the two existing instrument systems that monitor CST level to provide redundant indication and alarms in the control room by April 1, 1980.
One of the two loops will have a backup battery source.
In the interim, alternate indications will be provided for by dispatching an operator to read a temporary sight glass installed at the standpipes in the Turbine Building.
2.
Supplement Commonwealth Edison Response with:
Commonwealth Edison will also provide a summary of the test results including the items recommended by the Staff.
Both Zion units may not be operating prior to January 1, 1980.
Therefore, the recommended endurance test will be performed as soon as possible after each unit returns to operation.
3.
Supplement Commonweath Edison Response with:
Reference (c), a December 14, 1979 letter from D.
L. Peoples to D. G. Eisenhut providing an additional response to NRC Lessons Learned Recommendations 2.1.7a and 2.1.7b.
4.
Replace Paragraph 3 of Commonwealth Edison Response and Supplement with:
More specifically, as shown on Figure 2, the encircled valve (SW-0179) is the one valve that requires local manual realignment during periodic testing of the turbine-driven AFW pump system train.
This realignment is performed to allow operators to verify the operability of the motor-operated valve in series with it (MOV SW0102) without con-taminating the condensate storage tank, and utimately the secondary plant with service water.
The test procedure 1644 196
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Auxillary peedwater System
is designed to first verify operability of the turbine-driven AFW pump system train through the normal flow-path.
Once this is verified (with design flow reestablished to the steam generators), then the operability of MOV SW0102 is checked.
It is clear from Figure 2 that the realignment of the encircled manual valve will in no way interfere with the operaoility of the turbine-driven AFW pump system 2
train through the normal flowpath.
The test procedure then calls for realigning SW-0179 to its normal position and s
for management verification of realignment to normal position.
C.
Supplementary Response to Attachment 3 of Reference (b) 1.
Replace Paragraph 2 of Commonwealth Edison Response to GL-2 and Supplement with:
All three AFW pumps are designed to trip on low suction pressure.
These trips are annuciated in the control room.
In addition, as previously stated in Commonwealth Edison's response to NRC Recommendation GS-4 contained in Reference (b), emergency procedures that establish the criteria for transferring to alternate sources of AFW supply will be developed to cover the cases addressed by the NRC Staff in its recommendations.
These procedures will be implemented by January 1, 1980.
2.
Supplement Commonwealth Edison Response to GL-3 with:
This modification as described in the supplemental response to GS-5 will consist of providing a new and independent water supply line to these coolers.
This water supply line will originate from the turbine driven feedpump 1st stage discharge port and terminate down-stream of solenoid valve 1SVSW132 and upstream of line 1SW239-3/4".
This 1" water supply line will include a flow orifice assembly.
' pressure relief valve in order to
' maximum of 150 psig.
Solenoid regulate flow to 15gpm valve 1SVSW132 will be ueleted and the original service water supply to the coolers will be " capped off".
This design change will also include a modification to the bearing cooler return lines.
These return lines will be combined in a common header and will be routed to the re-circulating return line to the condensate storage tank.
Refer to Figure 1 which contains a preliminary sketch as well as flow diagrams M-22 and M-34.
Also, in the event of a loss of all AC power, the control room operator will regulate steam generator levels via communication with the AFW pump local operator who will start and stop the pump as necessary.
i644 198
In addition, an analysis is currently underway to determine the ambient area temperatures for the turbine driven auxiliary feedwater pump during the two (2) hours subsequent to a complete loss of AC power.
This analysis including an evaluation of equipment and component opera-bility during this ambient condition will.be provided to the NRC Staff by February 29, 1980.
2 3.
Supplement Commonwealth Edison Response to GL-4 with:
The NRC Staff's concerns about reestablishing AFW flow after a low suction pressure trip of the AFW pumps will also be addressed in the procedures being developed in response to NRC Recommendations GS-4 and GL-2.
I 7
9 1644 199 4