U-602770, Provides Update of Issue Concerning Neon Light Sockets & Inappropriate Use of Solder Flux at CPS

Provides Update of Issue Concerning Neon Light Sockets & Inappropriate Use of Solder Flux at CPS

ML20149K804
Person / Time
Site:	Clinton
Issue date:	07/02/1997
From:	Romberg W ILLINOIS POWER CO.
To:	Beach A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
U-602770, NUDOCS 9707300164
Download: ML20149K804 (2)

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11 ower Company Clinton Power Station

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P.O Box 678 '

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U-602770 4F.190~

July 2, 1997 PRIORIT'r Rt H flNG Docket No. 50-461 Fast Seconn RA RC Mr.l97BilMck N0'.04 EIC )

Regional Adminisgm t { ; D_R E iP A SGA .

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Region III ONMS PAO 801 Warrenville Road DRMA Lisle, Illinois 60532-4351 < / ]

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Subject:

Update ofIssues Concerning Neon Light Sockets and Inappropriate Use of Solder Flux at Clinton Power Station

Dear Mr. Beach:

Illinois Power (IP) is committed to updating you on our ongoing efforts at Clinton Power Station (CPS) concerning the replacement of main control room i indicating light sockets that were affected by the previous use ofincorrect solder flux, j and the investigation of other plant components where the incorrect flux may have been

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previously applied. This letter provides an update to IP's original letter dated June 10, i 1997 (U-602759), and subsequent letters dated June 19,1997 (U-602763) and June 20, i 1997 (U-602766) regarding this subject.

The reworking of over 590 neon light sockets in the main control room is approaching completion. As of June 26,1997, more than 500 light sockets have been replaced using the new repair techniques, and these lights have been tested with satisfactory results. As described in our June 19,1997 letter, the improved repair techniques involve no use of the inappropriate solder flux and eliminate any detrimental i effects from the previous use of the inappropriate solder flux.

O The preliminary results of the investigation of this event determined that the root cause was a programmatic breakdown in the control of consumable materials (e.g.,

solder flux) at CPS in conjunction with questionable workmanship. IP's corrective actions will not only address the control of solder flux but also the generic control of \

consumable materials at CPS. IP's short-term corrective actions, as identified in our g\

June 10,1997 letter, have established a means to prevent further use of the incorrect solder flux in electrical applications. /,y\'f

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, .- U-602773 Page 2 of 2 4

As stated in our June 20,1997 letter, our ongoing investigation into the

. inappropriate use of the subject solder flux identified that the flux may have been f

applied to safety-related plant components other than the neon light sockets. The potentially affected components identified were the Source Range Monitor "B" (IC51K600B) containment penetration connection and eleven solid-state trip devices i associated with 480-volt circuit breakers. Through interviews with the electrical maintenance staff, it was determined that the eleven solid-state SS-14 trip devices did not have the incorrect flux applied during maintenance activities. However, as a conservative measure, IP decided to replace the eleven trip devices, and that replacement work is in progress. Reworking Source Range Monitor "B" is planned to be complete prior to stanup from RF-6. This will require removing the section of

, potentially affected cable at the containment penetration where the incorrect solder flux

may have been used and installing a new connector per vendor recommendations.

l Otherwise, the review of all safety and non-safety related work documents to determine 4

where the subject flux may have been used in other applications is complete, and no

further actions as a result of that review are required.

I In addition to the above investigation, IP has identified other types of solder flux

that may be potentially corrosive in nature and is investigating where it may have been i applied to plant components. As a result of that review, six maintenance work

documents have been generated for reworking / replacing potentially affected 1

components. These components include another ponion of the cable / cable connections a

for SRM "B" and the cables / cable connections for several intermediate range monitors.

The solder flux that may have been applied to these components was applied many years j ago (in the time frame from plant constmetion up to approximately three years ago),

and there does not appear to be any adverse effects from the application based on the 1

continued operability of the potentially affected components. Nevertheless, the work

documents have been prepared and are scheduled to be completed prior to December i 31,1997.

) IP will continue providing updates on the issue in accordance with this commitment. Ifyou have any further concerns or questions, please contact me.

Sincerely yours,

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n 6&y U i Wayne D. Romberg i Assistant Vice President

, BGS/krk cc: Document Control Desk NRC Clinton Licensing Project Manager NRC Resident Inspector Office, V-690 Illinois Department ofNuclear Safety a