ML20214Q903
| ML20214Q903 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 05/29/1987 |
| From: | Leblond P COMMONWEALTH EDISON CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| 3131K, TAC-61855, TAC-61856, NUDOCS 8706050253 | |
| Download: ML20214Q903 (5) | |
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/ Address Reply to: Poet Office Box 767 Y/ CNcago, Illinois 60690 - 0767 May 29, 1987 11.S. Kuclear Regulatory Conniosion Attn: Document Control Desk Washington, DC 20555
Subject:
Zion Nuclear Power Station Units 1 and 2 Second Interval Inservice Testing Program TAC Nos. 61855/61856 NRC Cocket Nos. 50-295 and 50-304
Reference:
June 17, 1986 letter from P. C. LeBlond to H. R. Denton.
Dear Sir:
The referencei letter transmitted an updated set of relief requests for Zion Station's Inservice Testing (IST) program. Included with that transmittal were a large number of program refinements that resulted froic an extensive program review. The referenced letter was also intended to sunraarize all previous correspondence regarding Zion's Sacond Interval IST program and to provide a comprehensive review document for the IST program revisions.
This sutmittal is revising three pages of the information supplied in the referenced letter. Revised pages 1*D, 186, and 234M are enclosed. Please utilize these pages to replace the corresponding pages supplied in the reference.
These changes are being made as a result of the failure of the ultrasonic flow instrumentation that was instulled on Zion's Service Water (SW) system. The flow indit,ation output did not vary with different SW pump combinations. In addition, the signal fluctuated widely.
It appears that the ultrasonic flow instrumentat,1.on may have been an inappropriate choice for this application. As a result, Zion Station intends to investigate various flow measurement methods to identify a system that will function accurately within the physical constraints of the SW system. The revised flow instrumentation syutem is' expected to be installed during the two 1988 refueling outages.
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Since the ultrasonic flow instrumentation used for demonstrating service water pump check valve operability is currently nonfunctional, check valve operability will be verified by other positive means. This affects ISW0001, ISW0004, ISWOOO7, 2Swo001, 2sv0004, and 2SWOOO7. Check valve operability will be verified by comparing differential pressures across the check valves, audibly verifying that the valve closes when the associated pump 2
stops, and verifying that the valve closes by observing zero pressure on the pump side of the valve with the pump stopped. These indications verify valve operability in both the open and closed positions. These changes are reflected la pages 186 and 234M.
1 Page 177 discusses the effect of the flow instrumentation deficien-cies on the testing of the SW pumps. The revised Pump Relief Request (#2) will not decrease the margin of safety for the plant because the monthly pump performance surveillances for the service water pumps required by Zion Technical Specification Section 4.8.7 will continue to be performed. This I
test verifies that the pumps start and operate properly fer 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
In addition, pump vibration is also monitored and trended.
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t If any further questions arice regarding-this matter, please direct i
them to this office.
Very truly yours, 1
4 l
P. C. LeBlond Nuclear Licensing Administrator 4
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Attachment
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cc: Resident Inspector
'! ion J. A. Norris - NRR I
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3131K i
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9 Pump Relief #2 Relief is requested from pressure and flow measurements for Service Water Pumps SW001, 2 and 3.
Code Requirement Individually test pump per IWP-3400(a), pressure measurements and flow measurement per IWP-3100.
Basis and Alternate _
Service water pumps are of vertical design with no means to measure direct inlet pressure. The inlet pressure to these pumps will be established by reference to the level of lake water above pump suction.
Measuring inlet pressure with the pump idle is not necessary because the level in the forbay will not change by an appreciable amount before and after the operation of a service water pump.
Individually flow testing each pump at times other than refueling outages would jeopardize safe plant operation and may conflict with the Technical Specifications.
During refueling outages when it is permissible to run one pump at a time, individual flow measurements will be taken in the common discharge header for each pump. A situation may occur when it is required by the Technical Specifications that the cross-tie remains open between Unit 1 and Unit 2 service water systems (i.e., a service water pump is out of service for a major overhaul).
The individual flow rates of the pumps cannot be measured while the cross-tie is open since the flow instrumentation is located down stream of the cross-tie.
If this situation should occur for tne duration of the refueling outage, this test will not be performed. The flow measurements will be used to calculate a reference differential pressure from the manufacturer's pump curve and this value will be compared to the measured differential pressure to insure that the pump is operating within 110% of the established pump curve. Additional relief may be necessary after data is analyzed from the first inservice test.
Flow rate and differential pressure through the service water pumps vary depending on plant conditions, how many pumps are running and the demand on the system. Therefore consistent reference values cannot be established. Since the measured flow rate is used to determine the reference differential pressure from the pump curve and this is only performed during refueling outages, the parameters used to calculate differential pressure (i.e.
inlet and outlet pressures) will also be measured only at refueling outages.
It is impractical and meaningless to take measurements that cannot be compared to a reference value.
Past plant design did not incorporate individual pump discharge flow instrumentation. Flow instrumentation was installed in the common discharge header because it is the closest area near the pump with sufficient straight length pipe to install accurate flow instrumentation. The first test was to be run on U-1 during the 1986 refueling outage. However, the flod instrumentation did not perform properly and could not be repaired.
Zion Station is currently investigating three new methods to measure flow.
Zion Station proposes to install new flow instrumentation on Units 1 and 2 during their next scheduled refueling outages in 1988.
As required by Zion's Technical Specifications, a monthly operational test is performed to insure that the pumps are providing adequate cooling throughout the plant. This alternative will provide adequate assurance of continued operatient.1 readiness.
177 11110 l
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System: SERVICE WATER ZION UNIT 1 and 2 Revisici 1 Date 8-09-85~ ' C-INSERVICE TEST PROGRAM M-32-1 ASME CODE CLASS 1, 2, AND 3 VALVES 1
TEST V N CC UDL V
VT AT T
MST RR UDL A U 0L 1R0 AS AY CY E
ATI EE 2R0 L M DA AC LI LP TP S
.V E UE T
IOE IU WA E E S
IT VALVE EE E
A MK EE IT R
NI CATEGORY T
UE FS NI REMARKS 60 0
M T
GO N
A B
C R
N SW0001 3
B-7 X
24 C
S EQ B-1 1
SWOOO4 3
B-6
-X 24 C
S EQ B-2 SWOOO7 3
B-5 X
24 C
S EQ B3 OMOV-SW0005 3
E-6 X
14 B
M0 EQ 60 E-6 OMOV-SW0006 3
D-6 X
14 B
M0 EQ 60 D-6 t
i t-I i
1 w-j 11110 186
Valve Relief #26 Withdrawn (Proper valve operation will be verified by other positive means as permitted by IWV-3522.)
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234M 11110