ML20246H878

Forwards Addl Info Re Util 890310 Tech Spec Change Request to Revise Calibr Frequency for source-range Monitor & intermediate-range Monitor Detector Not in Startup Position for Control Rod Block Actuation,Per 890419 Request

ML20246H878
Person / Time
Site:	Peach Bottom
Issue date:	05/05/1989
From:	Hunger G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 8905160214
Download: ML20246H878 (4)

Text

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'C .10 CFR 50.90 4

PHILADELPHIA ELECTRIC COMPANY'

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2301 MARKET STREET l P.O. BOX 8699 PHILADELPHIA A. PA.19101 (215)841 4000 May 5, 1989 Docket Nos. 50-277 50-278 License Nos. DPR-44 DPR-56 U.S. Nuclear' Regulatory Commission Attn: Document Control Desk Washington, DC 20555'

SUBJECT:

NRC Request for Additional Information Regarding Peach Bottom Atomic Power Station Technical Specification Change Request for SRM, IRM Detector Not In Startup Position Calibration

REFERENCE:

1) Letter from R. E. Martin (NRC) to

~G. A. Hunger, Jr. (PECo) dated April 19, 1989

2) Letter from G. A. Hunger, Jr. (PECo) to USNRC dated March 10, 1989

Dear Sir:

This letter is in response to the subject Request for Additional Information (Reference 1) regarding the Peach Bottom Atomic Power Station (PBAPS) Technical Specification Change Request (Reference 2). The purpose of the Technical Specification Change Request is to revise the calibration frequency for the Source

. Range rionitor (SRM) and Intermediate Range Monitor (IRM) Detector Not In Startup Position instrument chenn?ls for control rod block actuation.

The attachment to this letter provides our response to each of the questions of the Request for Additional Information.

If you have any further questions regarding this Technical Specification Change Request, please do not hesitate to contact me or my staff.

Very truly yours,

. N. i .

G. A. Hunger, Jr.

Director Licensing Section Nuclear Support Division

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Document Control Desk .May 5,-1989

. Page 2 3; cc: W.'T. Russell,' Administrator, Region I,.USNRC

.T. P.~ Johnson, USNRC Senior Resident' Inspector T. E.-Magette, State of Maryland J. Urban, Delmarva Power J. T. Boettger, Public Service Electric & Gas H. C. Schwemm,' Atlantic Electric' l

T. R. Gerusky, Commonwealth of Pennsylvania.

Y Attachment

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J Response to Request for Additional Information 1

1. PECo's proposal appears to rely on the assumption that the expected limit switch settings during operation, based on a calibration performed sometime during a refueling outage, would not be expected to be significantly different than if these settings were based on calibrations performed within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of startup or shutdown as now required. Please confirm or modify this assumption as appropriate.

Also, please clarify the meaning of the sentence "it can be demonstrated..." in l the Safety Discussion with respect to the presumed purpose of the application to show that indeed this is the case. '

Response

We confirm the assumption.

The sentence "It can be demonstrated that calibration of these instrument channels at the existing frequency is not necessary, based upon the Standard Technical Specifications for General Electric Boiling Water Reactors NUREG-0123, vendor recommendations, and past surveillance history" provides the bases for the technical specification change request's conclusion that conducting the '

surveillance at the existing frequency is not necessary. The sentence is a lead into the three paragraphs that follow it in the Safety Discussion which demonstrate the bases. From our perspective the phrase "It can be demonstrated that" could be deleted and not change the intent of the sentence.

l 2. Given that the limit switches utilize a chain and sprocket arrangement, please l discuss tne design features susceptible to drift between calibrations and thus in need for calibration. Also, please provide a summary of the referenced surveillance history with respect to the assumption that calibration sometime during each refueling outage will provide comparable assurance of operability as would calibration at the presently stated TS frequencies.

Response '

The limit switches used in the SRM and IRM detector drive mechanisms are not subject to setpoint drift. The limit switches are mechanical control devices comprised of a chain and sprocket assembly, gears, and electrical contacts. If one of the device's components fails, the switch will not operate.

l The surveillance history referenced in the technical specification change I request is functional test data for the SRM and IRM position channels. The

! functional tests verify the instrument channels to be operable. The tests l require the detectors to be fully inserted and then withdrawn. During the I withdrawal phase, the detector IN light is verified to turn off and the rod l l withdrawal block is verified to alarm. The data reviewed to support the l technical specification change request was for functional tests performed l during refueling outages from 1978 to the present. t In summary, since the limit switches are mechanical devices and not susceptible to setpoint drift, performing the preventive maintenance re-alignment each refueling outage provides adequate assurance of correct detector position, and 1

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functionally testing the instrument channels at the existing' frequency assures I the operability of the instrument channels. Therefore, the requested Technical Specification change provides comparable assurance of the instrument channel .

operability as would calibration at the present Technical Specification I frequency.

3. The principle justification for the requested change appears to be that

' calibration essentially the same as that now required by the.TS will continue to be done but at an alternate time in each fuel cycle. That is, instead of being done near startup and shutdown, when containment environmental conditions pose personnel hazards, the calibration will be done during each refueling  ;

outage as part of the preventive maintenance program. Please address this matter and provide a reference to the PECo document which defines the requirement to do this preventive maintenance during each refueling outage.

Response

The preventive maintenance re-alignment of the detector drive mechanism provides the calibration required by the existing technical specification.

However, the principal justification for the requested change is that the '

currently required calibration of the Detector Not In Startup Position is not needed, at any frequency, since the limit switches are not subject to drift.

The limit switches are adjusted and aligned as part of maintenance of the detector drive units, since the maintenance activity involves disassembly and reassembly of the drive components. If the maintenance was not performed, the limit switch setpoints would not change. The procedure M-4.501, " Source Range Monitor / Intermediate Range Monitor (SRM/IRM) Drive Unit Maintenance" is performed as a requirement of the Administrative Procedure A-25.1, " Instrument Preventive Maintenance Program." The activities covered in A-25.1 are controlled and documented using the Computerized History and Maintenance Planning System (CHAMPS) in association with procedure A-26, " Corrective and Preventive Maintenance Using CHAMPS." The CHAMPS data base currently requires l performance of drive unit maintenance procedure A-4.501 for the SRM and IRM  !

instrumentation during each refueling outage.

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