ML20084H473

Discusses Determination of Equipment within Scope of 10CFR50.49(b)(2).Components Added & Removed as Result of Internal Reviews by CNS Plant Engineering,Consultants & Further Engineering Studies

ML20084H473
Person / Time
Site:	Cooper
Issue date:	03/22/1984
From:	Pilant J NEBRASKA PUBLIC POWER DISTRICT
To:	Vassallo D Office of Nuclear Reactor Regulation
References
TAC-42486, NUDOCS 8405080072
Download: ML20084H473 (2)

Text

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GENERAL OFFICE j

j Nebraska Public Power District

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"5 March 22,1984 Director of Nuclear Reactor Regulation Operating Reactors Branch No. 2 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attention : Mr. Domenic B. Vassallo, Chief

Reference:

1.

Letter from H. R. Denton to All Operating Light Water Reactors, September 17, 1979 2.

Letter from J. M. Pilant to H. R. Denton, October 8,1979 3.

Letter from J. M. Pilant to D. B. Vassallo dated May 20, 1983

Subject:

Determination of Equipment Within the Scope of 10CFR50.49(b)(2)

Paragraph (b)(2) of 10CFR50.49 requires that licensees identify "Nonsafety-related electric equipment whose failure under postulated environmental conditions could prevent satisfactory accomplishment of safety-functions..."

The District originally performed this analysis with the results documented in Reference 2.

However, several new analyses and evaluations have been performed since that time.

Therefore, the previous assessment has been modified to include the impact of a revised HELB study, and the further equipment requirements identified in I.E. Bulletin 79-01B,10CFR50.49, and Reg. Guide 1.97.

The re-evaluation was performed using the following methodology to identify the subject equipment:

1.

A list was generated of safety-related electric equipment as defined in Paragraph (b)(1) of 10CFR50.49 required to remain functional during or following design-basis Loss ot' Coolant Accident (LOCA) or High Energy Line Break (IIELB) accidents.

The LOCA/HELB accidents are the only design-basis accidents which result in significantly adverse environments to electrical equipmcat which is required for sate shutdown or accident mitigation.

This li.st was based S # l N 8405080072 840322 PDR ADOCK 05000298

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4 Page 2 March 22,1984 on reviews of the Piping and Instrument Diagrams (PAID's),

Electrical Elementary Diagrams, and Electrical Distribution Diagrama.

2.

The elementary wiring diagrams of the safety-related electrical equipment identified in Step 1 were then reviewed to identify any auxiliary devices electrically connected directly into the control or power circuitry of the safety-related equipment (e.g.,

automatic trips) whose failure due to postulated environmental conditions could prevent the required operation of the safety-related equipment.

3.

N ext, the operation of the safety-related systems and equipment were reviewed to identify any directly mechanically connected auxiliary systems with electrical components which are necessary for the required operation of the safety-related equipment (e.g.,

cooling water or lubricating systems).

4.

Finally, the nonsafety-related electrical circuits indirectly associated with the electrical equipment identified in Step 1 by common power supply or physical proximity were considered by a review of the original Cooper Station electrical design.

The systems and equipment generated in Steps 2, 3, and 4 above were then compared to the " Master List of Electrical Equipment at Cooper Nuclear Station for 10CFR50.49" dated '

May 20, 1983, Reference 3.

Components have been added and removed as a result of internal reviews by CNS Plant Engineering, consultants, and further engineering studies.

All of the added equipment was determined to meet the classification of paragraph (b)(1) of 10CFR50.49.

No additional equipment was found to be applicable to (b)(2) of 10CFR50.49.

If you have any questions regarding this matter, please contact my office.

Sincerely, W.

.1. Pilant i.

Technical Staff Manager Nuclear Power Group JMP/kew:cm::20 /4

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