ML19269E407

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Submits Addl Info Re Manual Bypasses of Actuation Sys Signals,In Response to NRC Telcon Request.Clarifies Items Identified During Investigation of Safety Actuation Circuits Incorporating Manual Override Features
ML19269E407
Person / Time
Site: Calvert Cliffs  Constellation icon.png
Issue date: 06/21/1979
From: Lundvall A
BALTIMORE GAS & ELECTRIC CO.
To: Reid R
Office of Nuclear Reactor Regulation
References
NUDOCS 7906280135
Download: ML19269E407 (2)


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. N BALTIMORE GAS AN D ELECTRIC COMPANY GAS AN D ELECTRIC BUILOING BALTIMORE, MARYLAN D 21203 Antwun E. LvNovALL JR.

vies pass.ose ' g79 sum, Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555 Attention: Mr. Robert W. Reid, Chief Operating Reactors Branch #4 Division of Operating Reactors Subj ect: Calvert Cliffs Nuclear Power Plant Unit Nos. 1 and 2 Docket Nos. 50-317 and 50-318 Manual Bvoasses of ESFAS Sinnals Ref: BG&E letter dated April 10, 1979 from A. E.

Lundvall, Jr. to R. W. Reid on Manual Bypasses of ESFAS Signals Gentlemen:

The referenced letter discussed our intentions with regard to six items identif*.ed during our investigation of safety actuation circuits incorporating manual override features which was conducted pursuant to your letter of November 29, 1978 on this subject.

In a subsequent telephone conversation with your staff, it was determined that some additional clarf.fication was necessary. This is pro-vided below.

The description of the switchgear room air conditioning system contained in the referenced letter (item a.) was in error. The control switches for the switchgear room circulating air fans are located in an HVAC equipment room above the switchaear roca at Elevation 69' of the Auxiliary Building. Each of the two circulating air fans is interlocked with a compressor. One fan-compressor pair handles the existing air-conditioning load while the other fan-compressor pair is kept on stand-by.

Increasing temperature in the switchgear room caused by any failure of the operating fan-compressor pair is annunciated in the control room. On receipt of a switchgear room high temperature alarm, a man is dispatched to the HVAC equipment area to start the stand-by fan-compressor pair. There is sufficient time for start-up of the stand-by fan-co=prescor pair after receipt of the alarm to protect the equipment in the switchcear room.

Normally, start-up and shutdown of a fan-ccupressor pair is accomplished by means of the fan on-off switch. Since the current method of operation and \

2170 163 h'o 7906280/3 5 0

a Mr. Robert W. Reid June 21, 1979

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control of the switchgear room HVAC equipment is considered satisfactory, we intend to leave the circulating air fan control switches in place as the nomal means of system control. In addition to these fan control switches (which are interlocked with the compressors), there are local switches in the HVAC room which allow the shutdown of the compressors without shutting down the companion circulating air f ans. We are no longer considering the removal of these switches since all of the switches are located in the switchgear room HVAC equipment room, which is the nomal location for system control and operation.

A change in the annunciator logic for the " Service Water Heat Exchanger Isolated" alarm (ites c. in the referenced letter) will be modi-fied such that the "SIAS signal present" pemissive for the isolation alam will be removed. This will ensure that the " Heat Exchanger Isolated" alam will be generated whenever the salt water inlet or outlet valves are closed.

Please do not hesitate to contact us if you need additional infor-mation or if you have cou:ments on our proposed changes.

Very truly yours

. , . n- _ AM .

. E. LLnd"all, Jr.

VicePresitent-Supply [

ec - Messrs. J. A. Biddison, Jr., Esquire G. F. Trowbridge, Esquire E. L. Conner, Jr. - NRC 2170 161/