ML20079H121

Suppls 831222 Response to Nrc,Per 831223 Telcon,Re Violations Noted in IE Insp Rept 50-373/83-50.Addl Info Re Adequacy of Visual Insp Techniques to Determine Condition of Cables at Higher Elevations of Drywell Provided

ML20079H121
Person / Time
Site:	LaSalle
Issue date:	12/27/1983
From:	Schroeder C COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20079H087	List: ML20079H121 ML20079H139 ML20079H154
References
7876N, NUDOCS 8401230334
Download: ML20079H121 (2)

Text

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/^'N Commonwealth Edison

) one First NItionai Plaza. Chicago. Dhnois

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t C 7 Address Reply to: Post Office Box 767 4

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,,, \ / Chicago, Illinois 60690 December 27, 1983 Mr. James G. Keppler Regional Administrator U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, IL 60137

Subject:

LaSalle County Station Unit 1 High Drywell Temperature NRC Docket No. 50-373

Reference:

(a) C. W. Schroeder letter to J. G. Keppler dated December 22, 1983 transmitting report on Unit 1 High Drywell Temperature

Dear Mr. Keppler:

This letter supplements reference (a) to support the immediate restart of LaSalle Unit 1 following the recent overtemperature experience in the drywell. Members of your staf f had requested additional information on two topics. The first question concerns the adequacy of the visual inspection technique to de? ermine the condition of cables at the higher elevations of the dr, well and specifically what type of verification ef forts were used to talidate the inspection. The second question addressed the need for assurance that the cable splices incorporated with the replacement cables are capable of in-containment service and conform with industry standards.

As indicated in the referenced report, the visual inspection of cabling in the upper zones of the Unit 1 drywell was correlated with engineering calculations for remaining life based on the same Arrhenius methods used to predict the initial life of the cable. The safety related cables were removed and replaced above drywell elevation 796 feet as were most non-safety related cables.

The visually indicated damage was confined to elevations above 804 feet. The analysis indicated that the selection of 796 ft.

elevation for cable replacement was valid (see Table IV-1 of the report). To confirm this decision on the replacement elevation,

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• R three cables representative of the drywell cabling have been removed

S5 for confirmatory testing at Wyle Laboratories. One of these is an 8@ SRV actuator cable which had a local hot spot where it was exposed gg to a heated pipe; the other two cables are vertical run cables that og were judged to be undamaged and representative of elevations extending from the lower drywell to the upper drywell. The testing of these cables follows IEEE 383 standards for functionality and gg acceptance. These cables are also to be tested through a LOCA Ago exposure to validate their " remaining life" by test. Results from .

the confirmatory inspector when completed. tests will be made available to the residentua C 2 8 1983

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-The cable splices were discussed under Section IV-3 on page 8:of the report where it'was stated that the splice positions used in the cable replacement were consistent with the original LaSalle criteria, i.e. splices were not used in cable trays, conduits or duct. runs but were located inside junction boxes, pull boxes, or at the primary containment penetration connection. These splices were made under approved field installation procedures based upon the vendor's recommendations for cable butt splices. The splices at the penetration position are approved splices; however, because they do not conform to the Commonwealth Edison standard for a single splice (rather than two splices), they will be removed at the first refueling outage and the single conforming splice will be installed at'that position.

With these clarifications to the referenced report, Commonwealth Edi. son's follow-up actions are now on record to assure that the Unit 1 cabling and equipment can credibly function for the i

" remaining life' represented in the report. l l

To the best of my knowledge and belief the statements )

contained herein are true and correct. In some respects these  !

stetements are not based on my personal knowledge but upon l information furnished by other Commonwealth Edison and contractor employees. Such information has been reviewed in accordance with company practice and I believe it to be reliable.

If there are any further questions in his matter, please contact this of fice.

Very truly yours,

/

d7/93 C. W. Schroeder Nuclear Licensing Administrator GRC/pl Oc: NRC Resident Inspector - LSCS 7876N

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