ML20137A867

Requests Adjustment of Mod Completion Date for Section 4.26.3 Re Isolation Between Reactor Protection Sys Channels & Power Supplies,Per ,To Allow Mod Performance During 1987 Refueling Outage

ML20137A867
Person / Time
Site:	La Crosse File:Dairyland Power Cooperative icon.png
Issue date:	11/14/1985
From:	Taylor J DAIRYLAND POWER COOPERATIVE
To:	Zwolinski J Office of Nuclear Reactor Regulation
References
LAC-11243, NUDOCS 8511260123
Download: ML20137A867 (2)

Text

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N D DA/RYLAND f

h [k COOPERATNE

• P.O. BOX 817 2615 EAST AV SOUTH

• LA CROSSE. WISCONSIN S:601 (608) 788-4000 November 14, 1985 In reply, please refer to LAC-11243 DOCKET NO. 50-409 U. S. Nuclear Regulatory Commission Attn: Mr. John Zwolinski, Chief Operating Reactors Branch #5 Division of Licensing Washington, DC 20055

SUBJECT:

DAIRYLAND POWER COOPERATIVE I LA CROSSE BOILING WATER REACTOR (LACBWR) I l PROVISIONAL OPERATING LICENSE NO. DPR-45 NUREG-0827 SUBMISSION OF DATA

REFERENCES:

(1) DPC Letter, F. Linder to W. Paulson, LAC-10491, dated January 3, 1985.

(2) NUREG-0827, Integrated Plant Safety )

Assessment of the Systematic Evaluation Program of the La Crosse Boiling Water Reactor.

Dear Mr. Zwolinski:

This letter requests that the modification completion date for one item discussed in Reference 1 be adjusted as follows:

1) Section 4.26.3, Isolation between Reactor Protection System Channels and Power Supplies The modifications as listed in Reference 1 were completed during the 1985 refueling outage. Signal isolation devices for the nuclear instrumentation, power supplies to the source and intermediate range nuclear instrumentation, and safety system pressure channels were separated as discussed in Reference 2.

The remaining commitment to separate the power supplies to the two safety system power to flow channels was deferred due to a concern of overloading the 1A 1KVA instrument inverter. DPC is moving forward with plans to install a larger instrument inverter in conjunction with the replacement of the 20 year old Generator Plant Battery and Battery Charger. This new capacity will provide the additional source of power to allow LACBWR to separate redundant equipment in future additions or modifications of equipment, thereby improving the reliability of this equipment.

As DPC addresses the aging and resulting difficulty in obtaining spare e

WPl.4.6 8511260123 851114 I (l P PDR ADOCK 05000409 - t P PDR 's

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ . ~ _2

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Mr. John Zwolinski, Chief November 14, 1985 Operating Reactors Branch #5 LAC-11234 parts of LACBWR equipment, the replacement of the nuclear instrumentation has been given high priority. A purchase order was issued in the summer of this year to procure a new General Electric nuclear instrumentation system.

Originally, it was hoped to install this equipment in conjunction with the new Generator Plant Battery System and new instrument inverter. Due to estimated delivery date on the nuclear instrumentation, LACBWR will not be able to install the nuclear instrumentation during the 1986 refueling outage. As part of the replacement of the nuclear instrumentation the power to flow circuitry is also being modified.

Currently, there are two channels of power to flow circuitry with a one-out-of-two scram logic supplied power by the 1B Inverter. Failure of the power supply and alternate source is unlikely. However, in tne event all AC power is lost to these channels, the fail safe design will ensure the safety functions will be completed. The new nuclear instrumentation design will incorporate some of the protective features presently installed in the power-to-flow drawers. Coordinating the separation of power supplied to the power to flow drawers and installation of new nuclear instrumentation modification will minimize the impact on plant operators, engineers, control document changes, training, overall cost, and reduce the possibility error.

To prevent duplicating and compounding design modifications and installations during two successive refueling outages for modifying the power supply sources to the power to flow circuits, DPC requests the modification be permitted to be performed at the same time the nuclear instrumentation is installed. This is currently scheduled for the 1987 refueling outage.

Please contact us if you have any questions.

Sincerely, DAIRYLAND POWER COOPERATIVE James W. Taylor General Manager JWT:RMB:sks cc: Mr. James G. Keppler, Region III NRC Resident Inspector Mr. John Stang, LACBWR Project Manager WPl.4.6 7