ML20010F103

Interim Deficiency Rept 1 Re Loss of Solid Metallic Grounding of Flexible Conduit,Initially Reported on 801210. Field Disposition Instructions Issued.Work Will Be Completed Prior to Fuel Load.Next Rept by 811020

ML20010F103
Person / Time
Site:	Grand Gulf
Issue date:	08/31/1981
From:	Mcgaughy J MISSISSIPPI POWER & LIGHT CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
10CFR-050.55E, 10CFR-50.55E, AECM-81-302, NUDOCS 8109090370
Download: ML20010F103 (5)

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MISSISSIPPI POWER & LIGHT COMPANY Helping Build Mississippi EnMhtildd5 P. O. B O X 164 0, J A C K S O N, , MIS SIS S I P PI 3 9 2 0 5 3"

1. Usfs!ErTM,%',i" August 31, 1981 Office of Inspection & Enforcement y U. S. Nuclear Regulatory Commission ,

Region II j S)'

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101 Marietta Street, N.W.

Suite 3100 C/ M{f[ g]

Atlanta, Georgia 30303 q' UEi' O 31981 > L it 15 s u.s. ve> cura tra^rco Attention: Mr. J. P. O'Reilly, Director \q ("""

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Dear Mr. O'Reilly:

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SUBJECT:

Grand Gulf Nuclear Station Units 1 and 2 Docket Nos. 50-416/417 File 0260/15525/15526 PRD-80/70, Interim Report #1 Flexible Conduit Grounding AECM-81/302 On December 10, 1980, Mississippi Power & Light Crmpany notified Mr. P.

K. VanDoorn, of your office, of a Potentially Reportable Deficiency (PRD) at the Grand Gulf Nuclear Station (CGNS) construct'on site. The deficiency concerns the potential loss of solid metall grounding of the flexible conduit used by our NSSS Supplier in the Power Generation Control Complex (PGCC) equipment.

We have determined that this deficiency, had it remained uncorrected, could have adversely affected the safety of operations of the nuclear power plant and is reportable under the provisions of 10CFR50.55(e). Investigation is continuing into the reportability of this deU ciency under 10CFR21.

We expect to submit a final report by October 20, 1981. Attached is our interim report.

Yours truly,

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KDS:dr ATTACllMENT cc: See page 2 8

n109090370 010031 PDR ADOCK 05000 g/ j S

Member Middle South Utilities System

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Mri J.'P.'O'Reilly .AECM-81/302 NRC. Page 2

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l cc Mr. N. L. Stampley L Mr. R. B. McGehee

! Mr. T. B. Conner L -

Mr. Victor Stello, Director Office of Inspection & Enforcement

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U. S. Nuclear Regulatory Commission Washington, D.C. 20555

, 'Mr. G. B. Taylor ,

i South Misa. Electric Power Association l P. O. Bor. 1589 Hattiesburg, MS 39401 e

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T bec: Dr. D. C. Gibbs Mr. J. Leatherman ,

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.Mr. J. N. Ward' Manager.of BWR-6 Licensing Mr. J. P. McCaughy, Jr. General Electric Company Mr.EJ. D. Heaton 175.Curtner Avenue f

Mr. R.-Trickovic , San' Jose, ca. 95125 Mr. J. W. Yelverton 0 l-1 Mr. L. F. Dale

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Mr. C.-K. McCoy- -Mr. D. M. Houston

> Mr. T. H. Cloninger U. S. Nuclear' Regulatory Commission ,

l Mr.<R. A. Ambrosino Division of Licensing L v Mr. A. J. Iosue Washington, D. C. 20555 l

Mr. G. B. Rogers .

j. Mr. S. H. Hobbs ,

l. Mr. L'. E. Ruhland- Mr. J. Ma' tore L Mr. D. L. Hunt U. S. Nuclear Regulatory Comnission Mr. A. G. Wagner Division of Licensing.

l Mr. P. A. Taylor Washington, D. C. 20555 L PRD File

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' Attachment to AECM-81/302.

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Page 1 of 2 'i 4

INTERIM REPORT NO. 1 TO PRD-80/70 l' I. JDescription of'the Deficiency The flexible conduit contained.in Power Generation Control Comp'.ex (PCCC) l equipment, designed and supplied by General Electric, has a potential loss of solid metallt'c grounding at the termination cabinet and/or the

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i panel, i In the termination cabinet installations, the conduit is firmly attached l with a locking ring to a termination module, which is an acceptable l ground connection. However, the termination module is ultimately mounted' l on a painted (high electrical resistance) surface. No procedures had

! been issued by the manufacturer, to insure that the paint was removed l from the panel surfaces before termination modules were mounted, or to check that the termination module made a low-resistance connection to the i

panel steel.

! . In the NSSS this could af feet the Reactor Protection System, the Nuclear Steam Supply Shutoff System and the Neutron Monitoring System. This applies to icth Unit 1 and Unit 2.

i l One of the purposes of the flexible conduit is to provide a low resist-

! ance path- to ground under certain short-circuit conditions. This insures

!- that upstream fuses will melt and thereby prevent " hot shorts" which have l the potential for preventing the completion of a protective function (de-j energizing various circuits). There is the potential of loss of solid j metallic grounding of the flexible conduit either at the termination cab- -

l inet or at the panel. This has the potential for preventing operation of l fail-safe logic associated with the Reactor Protection System- There-l fore, this deficiency is reportable under the provisions of L 10CFR50.55(e).- The investigation into reportability under the provisions of 10CFR21 is continuing.

I' General Electric filed a report on this condition to the NRC under

! 10CFR21 on December 8, 1980. This was a letter to Mr. Victor Stello, l

Jr., Washington, D. C., from Dr. Glenn C. Sherwood, Manager of Safety and-Licensing Operation.

II. . Approach to Resolution of the Problem The cause of the deficiency is that there.was no procedure to insure that paint was removed from panel surfaces before termination modules were mounted. . Also, there was no procedure to check that the termination module makes a low-resistance connection to the panel steel. The.defi-ciency 'affects all flexible encduit in the PGCC.

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. . l Attachment to AECM-81/302 Fage 2 of 2 The NSSS. vendor (General Electric) has issued Field Disposition Instruc-

'tions-(FDI) WATP and WBNY to provide a method of grounding these flexible conduits. Clamps with ground wires.will be provided to insure a positive low resistance path te ground, which will correct the deficiency.

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To prevent recurrence of the problem, GE has issued a grounding require-ment procedure. .

III. Status of Proposed Resolution The Field , Disposition Instructions have been issued. Work will be com-pleted prior to fuel load.

l IV. Reason Why a Final Report Will Be Delayed l Mississippi Power & Light has not completed the. evaluation of the report-E ability of this deficiency under the provisions of 10CFR21.

i V. Date When Final Report Will Be Submitted We expect to submit our final report by October 20, 1981.

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