ML20247H517

Submits Supplemental Info Re Generic Ltr 88-17, Loss of Dhr. Evaluation of Rh Pump Motor Alarm Recommended That Inputs from Parameters Should Be Processed Through Computer W/Graphic Configuration Similar to SPDS Iconic

ML20247H517
Person / Time
Site:	Byron, Braidwood, Zion, 05000000
Issue date:	09/15/1989
From:	Chrzanowski R COMMONWEALTH EDISON CO.
To:	Murley T Office of Nuclear Reactor Regulation
References
0293T, 293T, GL-88-17, NUDOCS 8909200005
Download: ML20247H517 (4)

Text

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, \ /_ Address 72 West Adams Reply to: PostStreet, Chicago, Illinois OffEBoi7BT NJ Chicago, lilinois 60c00 - 0767 September 15, 1989 Dr. Thomas E. Murley, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

Byron Station Units 1 and 2 Braidwood Station Units 1 and 2 Zion Station Units 1 and 2 Generic Letter 88-17 Supplemental Information Loss of Decay Heat Removal NRC Docket Nos. 50-454/455. 50_4551L455. 4 and 50-2951_3D4

References:

(a) NRC Generic Letter 88-17, dated October 17, 1988 (b) December 30, 1988, letter from R. A. Chrzanowski to T. E. Hurley (c) January 31, 1989, letter from R. A. Chrzanowski to T. E. Murley

Dear Dr. Murley:

The referenced NRC Generic Letter requests the implementation of actions to (1) prevent the initiation of a complete loss of decay heat removal event, (2) mitigate the effects of a loss of decay heat removal event to prevent core damage, and (3) provide a closed containment if the core uncovers during a loss of decay heat removal event. Generic Letter 88-17 prescribes expeditious actions which should immediately ease the concern; and parallel, but longer term programmed enhancements that effectively address the root cause of the problems and permit greater operating flexibility.

The Commonwealth Edison response to the expeditious actions was submitted in reference (b) and the response to the programmed enhancements was submitted in reference (c). This letter provides a status of the second independent RCS level indication, the main control room Residual Heat Removal (RH) motor ampere alarm evaluation, the Technical Specification Amendments, and a description of the disciplines of plant personnel to receive the training on the Diablo Canyon event, related events, and lessons learned.

After completing the engineering evaluation for the second independent RCS level indicating system, Byron and Braidwood Stations will utilize a duplicate of the first level indicating system. A complete description and simplified drawing is contained in Attachment A. Zion Station will utilize the existing hard piped sightglass with a closed circuit television camera and a monitor in the main control room.

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4 Y Dr. T.E. Murley. -

2- September 15, 1989 L The Commonwealth Edison Nuclear Engineering Department completed the i

" evaluation of the RH pump motor ampere main control room al um. The alarm, if.

installed,: would annunciate when the RH pump motor amperes fluctuate.

However, when the amperes fluctuate, the airbinding of the pump has already

. progressed to a significant extent. The evaluation, therefore, recommended not to install the alarm. Instead, the evaluation recommended that the inputs from the RH system parameters should be processed through a computer with a graphic configuration similar:to the Safety Parameter Display System iconic.

At the present. time, the Stations are reviewing the evaluation recommendations. A decision will be made by November 1, 1989, concerning the use of a computer graphic to display the RH parameters.

l The Technical Specification Amendments under consideration are for Byron and Braidwood Stations. No Zion Station Technical Specification changes L have been identified. The status of the three Byron and Braidwood Technical Specifications are as foll'ows; l

(1) The engineering analysis and evaluation for lowering the minimum RH flow rate required by the Technical Specifications during refueling operations has been completed. A Technical Specification Amendment request will be submitted to the NRC by January 30, 1990.

(2) The engineering analysis and evaluation for the removal of the RH auto closure interlock function has been completed. The hardware modifications have been 171tiated and a Technical Specification Amendnient request will be submitted to the NRC by January 30, 1990.

(3) The engineering evaluation for the operation of one safety injection pump in the event decay heat removal capacity is lost and RCS inventory must be increased is completed. A Technical Specification Amendment request will be submitted to the NRC by February 28, 1990.

Finally, the following station personnel will receive training describing the Diablo Canyon event, related events, and lessons learned prior to each planned outage involving reduced inventory conditions.

Licensed Operators Non-licensed Operators Chemistry Technicians Technical Staff Primary Group Byron and Braidwood Stations will also train the Instrument Maintenance personnel prior to each planned outage involving reduced inventory conditions. Zion Station currently trains the Instrument Maintenance personnel every other year. The Zion training includes a simulator scenaiio that shows the Instrument Maintenance personnel the importance of accurate midloop instrumentation in the main control room.

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• ' V Dr. T.E. Hurley September 15, 1989 Please direct any quest'ons on this matter to this office.

Very truly yours-R. A. Chrzanowski Nuclear Li ensing Administrator cc: Resident Inspector - Byron Resident Inspector - Braidwood Resident Inspector - Zion L. N. Olshan - NRR S. P. Sands - NRR C. Patel - NRR Region III Office Office of Nuclear facility Safety - IDNS 0293T:1-3 i

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