ML20140G318

Special Rept Spr 85-005:on 850517,discovered That Nuclear Instrument Source Detectors N-31,N-32 & N-33 Did Not Meet 10CFR50 App R Requirements.Fire Watch Established & Mod to N-33 to Be Completed by 860331

ML20140G318
Person / Time
Site:	Summer
Issue date:	06/18/1985
From:	Dixon O SOUTH CAROLINA ELECTRIC & GAS CO.
To:	Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
SPR-85-005, SPR-85-5, NUDOCS 8507120610
Download: ML20140G318 (2)

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S SOUTH CAROLINA ELECTRIC & GAS COMPANY Post orrice 7e4 CptuotA. south CAnoWNA 29218 r l

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M ri } ** D D Nuc$e5."o',*e2rYo,.. 'dh June 18, 1985 Dr. J. Nelson Grace Regional Administrator U.S. Nuclear Regulatory Commission Suite 2900 101 Mariett'a Street, NW Atlanta, Georgia 30323

SUBJECT:

Virgil C. Summer Nuclear Station Docket No. 50/395 Operating License No. N P F- 12 Special Report (SPR 85-005)

Dear Dr. Grace:

Attached is a Special Report for the Virgil C. Summer Nuclear Station. This Special Report is required by Section 6 of the Technical Specifications.

Sh ou ld there be any questions, please call us at your convenience.

r- ery t u y yours,

\

hbW+vs hN 1 on, Jr.

RMF:0WD/csw Attachment cc: V. C. Summer K. E. Nodland T. C. Nichols, Jr./O. W. Dixon, Jr. R. A. Stough E. H. Crews, Jr. G. Pe r c iv a l E. C. Roberts C. W. Hehl W. A. Williams , Jr. J. B. Knotts, Jr.

D. A. Nauman S. D. Hogge Group Managers I&E Washington O. S. Bradham Document Man age men t C. A. Price Branch S. R. Hunt INPO Records Center J. F. Heilman ANI Lib r a ry C. L. Ligon (NSRC) NPCF File 8507120610 850618 PDR ADOCK 05000395

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O Dr. J. Nelson Grace SPR 85-005 June 18, 1985 EVENT DESCRIPTION On May 17, 1985 the Licensee's Appendix R Task Force id en t i f ie d that separation of the Nuclear Instrument (NI) Source Range (SR) Detectors (N-31, N-32, and N-33) did not meet the requirements of 10 CFR 50 Appendix R. The "B" train power supply for NI SR channel N-33 shares a common breaker with a 7200 volt cable which runs in the same fire. area ("B" train cable chase, Room 36-03CB) as the "A" train s ignal cab les for NI SR channel N-31 and N-32. A fire in this area c ou ld damage channel N-31 and N-32 and als o dis rupt power to N-33. These circuts are separated by a horizontal dis tance of greater than twenty feet; however, because of intervening c omb u s t ib l e s , i.e, insulation of electrical cables, the requirements of Appendix R are not satisfied.

There were no adverse consequences due to this event. Detector N-33 is the SR indicator located on the Control Room Evacuation Panel (CREP). A fire in the "B" train c ab le chase wou ld not require a Control Room evacuation or the use of the CREP.

Shutdown wou ld be accomplished from the Control Room using "A" train equipment.

CORRECTIVE ACTION The Licensee e s t ab lis hed a one hour fire watch patrol o f the area as required by Technical ' Specification 3.7.10, " Fire Rated As s emb li e s . "

A modification to the existing installation of NI-33 is presently being processed wh ic h will provide isolation of NI-33 from.NI-31 and NI-32. This modification will be implemented no later than March 31, 1986.

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