ML20045C751
| ML20045C751 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 06/15/1993 |
| From: | Storz L CENTERIOR ENERGY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 1-1014, NUDOCS 9306240304 | |
| Download: ML20045C751 (3) | |
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GNTERIOR ENERGY 6200 Ook Tree Boulevard Mail Address-Independence OH PO Box 94661 j
216-447 3100 Cleveland.OH 44101-4661 Docket Number 50-346 j
License Number NPF-3' Serial Number 1-1014 June 15, 1993 United States Nuclear Regulatory' Commission
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Document Control Desk Vashington, D. C.
20555 Subj ec t: Response to NRC Inspection Report Number 50-346/93009 Gentlemen:-
Toledo Edison (TE) received NRC Inspection Report 50-346/93009 (Log Number 1-2851) on May 24, 1993. During this inspection, an unresolved.
item was identified by the inspectors regarding surveillance-test acceptance criteria for the' Auxiliary Feedvater (AFV) pumps (Unresolved
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Item 93009-03). The NRC requested that TE provide a response to the'
=j identified concern addressing corrective measures taken by TE to resolve this issue and the impact of the identified concern on previous AFV pump surveillance tests.
This letter provides the requested response.
Each AFV pump at the Davis-Besse Nuclear Pover'St'ation (DBNPS) is.
presently required to deliver a minimum of 600 gallons per minute (gpm) of water to a Once Through Steam Generator (OSTG) at a pressure of 1050L psig. Accouiiting for the effects of system flow resistances, elevation differences and recirculation' flow,.the minimum pump performance criteria for AFV Pump 1-1 are 600 gpm flow nt 1236 psig pump discharge
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pressure. The minimum performance requirements for AFV Pump 1-2 are j
600 gpm flow at 1227 psig pump discharge pressure.
Performance of the current quarterly surveillance tests for the AFV pumps (DB-SP-03151 and DB-SP-03160) involve measuring the flov' rate, the pump suction pressure, the pump discharge pressure, and the' pump speed for.'each pump. This data is then " normalized" to a' reference 1 0; b\\
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Operating companies:
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Docket Number 50-346 License Number NPF-?
Serial Number 1-1014 Page 2 pump speed (nominally 3600 rpm) using pump affinity laws and compared 4
i to the acceptance criteria. This practice also facilitates comparison between pump tests for detection of pump degradation.
During the recent NRC inspection of.the DBNPS Inservice Testing Program it was noted by the inspectors that the pump performance parameters for AFV Pump 1-1 vere approaching the minimum criteria mentioned above.
The inspectors contendci that if instrument uncertainties were applied to the data measured during recent surveillance tests, the minimum flow
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and discharge pressure requirements may not have been met.
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Instrument uncertainties were not considered in the determination of
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the pump performance criteria mentioned above, nor are they typically considered in establishing performance criteria for other pumps in the 4
l DBNPS Inservice Testing Program. Reasons for not considering l
instrument uncertainties are 1) the pumps typically operate vell within the established design limits and the relatively minor variations introduced by instrument uncertainty are considered insignificant; 2) l the analyses of design basis events use conservative inputs and, as j
such, are insensitive to minor variations caused by instrument uncertainty; and 3) there is no specific industry or regulatory guidance regarding application of instrument uncertainty to process measurement devices.
Existing industry guidance (i.e., Regulatory Guide 1.105 and Instrument Society of America (ISA) Standard S67.04) for setpoint determination apply to instruments that provide automatic l
protective functions and not to process measuring equipment. Vith respect to ISA S67.04, a setpoint is defined as "a predetermined level at which a bistable device changes state to indicate that the quantity i
under surveillance has reached the selected value."
In response to the inspectors' concerns, TE reviewed the results of the last 12 quarterly surveillance tests for both AFV pumps. This review took into account calculated and/or actual measured instrument j
uncertainties of the test instruments.
In each case, the pump performance criteria vere above the established minimum values and the pump was considered operable.
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It is TE's intent to increase the operating speed of AFV Pump 1-1.
i This vill raise the pump operating parameters to a point vell above the minimum values such that instrument uncertainties are not significant.
Until the pump speed can be increased, TE vill revise procedures DB-SP-03151 and DB-SP-03160 to change the acceptance criteria for AFV pump testing to allow for instrument uncertainties and to specify that a
measured pump flow and discharge pressure vill be used to demonstrate pump operability. The procedure changes vill be made prior to the performance of the next quarterly surveillance tests.
l Docket Number 50-346 License Number NPF-3 Serial Number 1-1014 Page 3 l
Should you have any questions or require additional information, please contact Mr. Robert V. Schrauder, Manager - Nuclear Licensing, at (419) 249-2366.
Very truly yours, O
4 Louit F. Storz Vice President - Nuclear NKP/dle cc:
J. B. Hopkins, NRC Senior Project Manager J. B. Martin, Regional Administrator, NRC Region III S. Stasek, DB-1 NRC Senior Resident Inspector Utility Radiological Safety Board i
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