ML20071P891
| ML20071P891 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 12/17/1982 |
| From: | Lippold W BALTIMORE GAS & ELECTRIC CO. |
| To: | Clark R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8212290120 | |
| Download: ML20071P891 (2) | |
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p BALTIMORE G AS AND ELECTRIC COMPANY P.O. B O X 1475 B A LTIMOR E. M A R YL A N D 21203 C LVERT CL FFS NUCL WER PL ANT LUSOY, M ARYL AND 20657 December 17,1982 Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C. 20555 ATTENTION: MR. R. A. Clark, Chief Operating Reactors Branch #3 Division of Licensing
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit 2, Docket No. 50-318, DPR-69 Response to NRC Question on Cycle 5 Instrument Loop Uncertainties Gentlemen:
NRC staff posed a question relative to the similarity of instrument loop uncertainties on Unit 2, Cycle 5 and Unit 1, Cycle 6. The technique for developing instrument loop uncertainties for those plant parameters affected by the Unit 1, Cycle 6 and Unit 2, Cycle 5 reload designs and safety analyses is identical for both units. In some cases the components in
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instrument loops are not identical between the Units. In all cases, the
'i.1 manufacturer's stated tolerances or tolerances more conservative than C 1 stated by the manufacturer for a component are used in developing an instrument loop uncertainty. The instrument loop uncertainty is added algebraically to the setpoint of the plant parameter used in the safety analysis and thereby yields the value stated in the Technical Specifications. The instrument loop uncertainty includes an allowance for drif t based on plant experience. In some cases the value of the setpoint entered into the equipment is more conservative than specified in the Technical Specifications in order to ensure that unexpected drift rates and
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e 8212290120 821217 PDR ADOCK 05000318 p
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Office f Nuclear Rea' tor Regulation December 17,1982 Page 2 less than precise settings of instrument potentiometers can be accommodated without violating the value in the Technical Specifications.
Should you have any questions, please contact me.
Very truly yours, BALTIMORE GAS AND ELECTRIC COMPANY yJs[
' W. J. Lippold Nuclear Fuel Management WJL/fld Enclosure (40 copies) cc:
J. A. Biddison, Esquire G. F. Trowbridge, Esquire D.11. Jaffe it. R. Mills it. Architzel
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