ML040780250
| ML040780250 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 03/10/2004 |
| From: | Gallagher M AmerGen Energy Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 5928-04-20090 | |
| Download: ML040780250 (7) | |
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-AmerGen M
AmerGen Energy Company, LLC 200 Exelon Way Kennett Square, PA 19348 www.exeloncorp.com An Exelon Company 1 OCFR50.55a March 10, 2004 5928-04-20090 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 Three Mile Island, Unit 1 Operating License No. DPR-50 NRC Docket No. 50-289
Subject:
Reference:
Submittal of a Revised Request for Relief to the Requirements of 1 OCFR50.55a Concerning Third Ten-Year Interval Inservice Testing Program Letter from M. P. Gallagher (AmerGen Energy Company, LLC) to U. S. Nuclear Regulatory Commission, dated September 24, 2003 In the referenced letter, AmerGen Energy Company, LLC submitted for your review arid approval a proposed relief request in accordance with 1 OCFR50.55a, associated with the third ten-year interval Inservice Testing (IST) program for Three Mile Island (TMI), Unit :1. This relief request concerns pump testing requirements for the Nuclear Service Closed Cooling Water pumps. This proposed relief request has been revised based on a discussion with the U. S.
Nuclear Regulatory Commission staff on January 12, 2004. Attached is the revised relief request with revision bars highlighting the changes.
Based on a start date of September 22, 1995, the TMI, Unit 1 third interval IST program is required by 1 OCFR50.55a(f)(4) to comply with the requirements of the ASME OM Code-1 987, Operation and Maintenance of Nuclear Power Plants, including the OMa-1 988 Addenda.
The third ten-year interval began on September 22, 1995, and will conclude by September 22, 2004.
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Inservice Testing Program March 10, 2004 Page 2 If you have any questions or require additional information, please do not hesitate to contact us.
Very truly yours, Michael P. Gallagher Director, Licensing and Regulatory Affairs AmerGen Energy Company, LLC Attachment - Relief Request cc:
H. J. Miller, Administrator, Region 1, USNRC D. M. Kern, USNRC Senior Resident Inspector, TMI D. M. Skay, USNRC Senior Project Manager File No. 02078
Three Mile Island, Unit 1 Inservice Testing Program Page 1 RELIEF REQUEST P5
- 1. ASME Code Component(s) Affected:
The NSCCW (Nuclear Service Closed Cooling Water) pumps:
Tag No.
Component Type NS-P-1A Nuclear Service Closed Cooling Pump "A" Centrifugal NS-P-1 B Nuclear Service Closed Cooling Pump "B" Centrifugal NS-P-1 C Nuclear Service Closed Cooling Pump "C" Centrifugal
2. Applicable Code Edition and Addenda
ASME OM Code-1987, Operation and Maintenance of Nuclear Power Plants, including the OMa-1 988 Addenda for the third interval.
3. Applicable Code Requirements
OMa-1 988 Part 6 (paragraph 5.1, "Frequency of Inservice Tests") requires testing of each pump quarterly.
Additionally, OMa-1988 Part 6 (§4.6.5, "Flow Rate Measurement") requires flow rate measurement of each pump. OMa-1988 Part 6 (§5.2, "Test Procedure" item (d)) requires the determination of flow rate as it applies to testing an individual pump.
4. Impracticality of Compliance
In accordance with 10 CFR 50.55a(f)(5)(iii), AmerGen Energy Company, LLC (AmerGen) requests relief from the requirements discussed in the "Applicable Code Requirements". In order to comply with these code requirements, plant modifications would be necessary to install flow instrumentation to accurately determine individual pump flow rates. The current piping configuration would need to be modified by adding straight pipe runs to allow for accurate individual pump flow measurements. As an alternative, the three pumps will be tested on a
Three Mile Island, Unit 1 Inservice Testing Program Page 2 quarterly basis in three-paired combinations during the operating cycle. Allowable ranges will be established for test parameters (differential pressure, flowrate and bearing vibrations) per OMa-1988, Part 6, Table 3. Individual pump flow rates, differential pressures and vibrations will be measured during refueling outages and compared against individual pump reference values.
The NSCCW (Nuclear Service Closed Cooling Water) system includes four (4) 33 and 1/3 percent capacity nuclear services coolers, and three (3) 50 percent capacity Nuclear Services Closed Cooling Cycle Pumps (see attached diagram (Drawing Number 302-610)). This system, along with the Intermediate Cooling System, satisfies the cooling requirements of all nuclear oriented services other than decay heat and reactor building emergency cooling. In the event of a Loss-of-Coolant Accident, 100 percent redundancy of all nuclear services equipment is obtained by isolating nonessential items so that flow requirements are reduced to approximately half that of normal operation. Normally, with two pumps in service, system flowrate is approximately 5,500 GPM or greater, as compared to a single-pump accident-required design flowrate of 1,972 GPM. Individual pump testing demonstrates a flowrate 25% greater than the single pump, accident-required design flowrate for the NSCCW pumps. Therefore, both the normal system flowrate and the single pump flowrate exceed the accident-required design flowrate by a significant margin.
The system has three pumps that are arranged in parallel, and run in pairs by design. To ensure adequate cooling to system heat loads, two pumps are normally in service. The flow instrumentation for these pumps is a single flow indicator (0-7500 GPM) located in the common piping for all three pumps.
Consequently, flow for any given pump can only be measured when only that single pump is running in the system. Each pump has an individual suction pressure gauge (0-100 PSIG) and an individual discharge pressure gauge (0-200 PSIG). Pressure and flow instruments meet the accuracy requirements of OMa-1988, Part 6, Table 1 (+/- 2% of full scale). Attached is an isometric drawing of the piping (E-304-612, Revision 14).
System flow / heat removal requirements mandate that two pumps be kept in service while at power per the plant design. As a result, individual pump flow can not be determined during the operating cycle without causing the potential to overheat components essential to power plant operation. The alternate test method would provide a quarterly assessment of paired-pump mechanical and hydraulic performance and a refueling-frequency assessment of single-pump mechanical and hydraulic performance.
The quarterly tests to measure paired pump performance coupled with the refueling outage test to measure individual pump flow rates and routine preventative maintenance ensure the system will be capable of performing its
Three Mile Island, Unit 1 Inservice Testing Program Page 3 accident design function and that any pump degradation is identified. The alternate testing regime will ensure continued operability of the NSCC water pumps whose normal full-power operation continuously exceeds accident design flow requirements.
5. Burden Caused by Compliance
As described above, in order to comply with these code requirements, plant modifications would be necessary to install flow instrumentation to accurately determine individual pump flow rates during unit operation.
6. Proposed Alternative and Basis for Use
As described above, the alternate test method would be to test pumps in paired operation on a quarterly basis. Additionally, allowable ranges will be established for test parameters per OMa-1 988, Part 6, Table 3. This will allow degradation of the pump to be identified. If acceptance criteria are not met, an analysis will be made to demonstrate that pump operability is not impaired and the pump will still fulfill its safety function. If the analysis cannot support the operability of the pump, the pump will be repaired or replaced. These actions are in addition to: 1) individual pump testing performed during refueling outages, and 2) a system design that provides significant margin between normal power operation and accident design flow requirements. The alternate test methods will provide reasonable assurance that pump degradation will be detected and corrective actions taken to resolve pump performance issues prior to degrading individual pump design accident performance capabilities. The alternate test method is consistent with the previously approved relief request for these pumps.
7. Duration of Proposed Alternative
This relief is being requested for the third ten-year interval, which began on September 22, 1995, and will conclude by September 22, 2004.
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