ML20062L256

Deficiency Rept 29 Re Metal Potential Loss of Solid Metallic Grounding of Flexible Metal Conduit,Preventing Reactor Protection Sys Proper Operation.Ge Rept Encl.Flexible Conduit to Be Properly Grounded Per GE Instructions

ML20062L256
Person / Time
Site:	Limerick
Issue date:	01/13/1981
From:	Kemper J PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8101230434
Download: ML20062L256 (3)

Text

'

}&p<</

C7 orp~!f A $O

' (f , i f PHILADELPHIA ELECTRIC COMPAN i

'4, . '# #(/) 7-)

2301 MARKET STREET i ,, 9/ 4.% .,

c\*^ s P.O. BOX 8699 n ,** .sh ?

/,Q A, '/

PHILADEl. PHI A. PA.19101 T ,

/

(215)841-4502

$\ {-

JOHNS.KEMPER VIC E #R ESID E NT assoassaa esses aseo s.asamacu

,5 T - 3 52 5SS Mr. Boyce Crier, Director Office of Inspection and Enforecuent. "egion I United States ? uclear Regulatory Cons:ission 631 Park Avneue Kiug of Prusaia, PA 19406 l

22hject: Significant Deficiency v.eport 'l o . 29 Ceneral Electric Power Generation Control Complex - Grounding of Flexible Conduit Limerick Cenerating Station, Units 1 and 2

GC Construction ?cr. sic "os. C P P't - 10 f , 117 l

.Attschnents: a) Lettar ". ~ , . O .t '.' o s s (G") to 7. . A. "ulford

(?!CO) dated **12/19/N b) Letter G. C. .arvood (G?) to *l. 3tslie Jr. ("HC) d a t e c. 12/3/50 c) *)o cur:e n t "POCC 71exible ronduit Grounding' dated 12/3/30 File: CUAL 2_-10-2 (SD2 109) _

Dear Mr. Grier:

The attachments have brought to our attancion a deficiency in the subject General ".laceric ?over Caneratica Control Complex (?GCC) which has besn previously reported to the '7 0 ':" C Sy General 71ectric Company under the provisions of 10C77 ' art 21. The PGCC is beint supplied by General Electric for use at Line E k Generatine Station.

The deficiency consists of potential loss of solid metallic grounding of flexible metal conduit which could nravent p ro p.e r operation of the reactor protection system.

'J e consider the deficiency described in the att.achnents to be a significant deficisney per 10CFR $ 0. 33 (e ) and are haraby notifying you as r e <t ui r e d .

fe e ClaneeSkell THIS DOCUMENT CONTAIN[F 2iEfpag P00R QUAUTY PAGES 6 '/

810123 n yg

We believe that the Ceneral Electric report submitted under the provistoms of 10CF1 Part 21 provides the information required for 10CFR50.55(e) reporting. Therefore we anticipate that this letter will be our only report to you on the subject.

Ve will. of course assure that the subject flexible conduit at Limerack will be properly grounded in accordance with instructions received from Ceneral Electric.

Sincerely, C.Eds.'4A ,

f.

l RJL/gra Attachments Copy to: g BT~ rector of Inspection and Enforcement United States Nuclear Regulatory Commission Washington, D.C. 20555 J. P. Durr, USNRC Resident Inspector, LCS l

i l

l l

RIC NUCLEAR POWER l

SYSTEMS DIVISIO N GENERAL ELECTRIC COMPANY.175 CURTNER AVE., SAN JOSE, CAUFORNIA 95125 WAU-HC 391, (408) 925-5159 'g DEC  ;\

p,; i l 198U December 19, 1980 l

PE- 2443 bec: R. H. Logue l Mr. R. A. Mulford G. G. Sherwood l Project Manager W. W. Palmer LGS Units 1&2 '

2301 Market Street Philadelphia Electric Co.

-Philadelphia, PA 19101

SUBJECT:

LIMERICK GENERATING STATION, UNITS 1 & 2 REPORTABLE CONDITION - GROUNDING OF FLEXIBLE CONDUIT

Reference:

Telecon R. Clancy to T. Loughran of 12/1/80 This is to confirm the reporting of a reportable defect under 10CFR Part 21 first made to Mr. T. Loughran in the reference telecon. This defect is a potential for reactor protection system flexible conduit to develop hot shorts if improperly grounded. The defect was judged report-able on December 1,1980 and officially reported to Mr. Victor Stello, Jr. , ,

of the NRC by GE letter MFN-212-80 on December 8, 1980. Attached is the '

report of the defect and the action to rectify the issue.

Very tryly yours,

\

did .

l t I

H. G. DeVoss Project Manager Limerick Generating Station HGD:1m/1437 Attachment cc: R. H. Elias J. B. Roche W. J. Heal File: LB/3.1/3.11.3 l J. H. Walton/

i

• • e*a

I b . I i~ b .k f. Y [

5kf.bbYbkb NUCLLAR l' 0 W C R SYSTEMS DIVISION

. , *.i AL IILECTRIC . .* *.*MNY.175 CURTNCR AVE SAN JOSE.' CALIFORNIA 9',125 MC 662, (408) 925-5040 MFN 212-80 December 8, 1980 U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Washington, D. C. 20555 -

Attention: Victor Stello, Jr. , Director Gentlemen:

SUBJECT:

REPORTABLE CONDITION GROUNDING 0F FLEXIBLE CONDUIT This is to advise you of a reportable defect under 10CFR Part 21 as reported to Mr. Wayne Reinmuth, by Walter H. D' Ardenne, Manager, Safety .

Evaluation Programs on December 3, 1980. This defect is a potential for reactor protection system flexible conduit to develop hot shorts if ,

improperly grounded. The defect was judged reportable on December 1, 1980. Attached is the report of the defect and the action to rectify the issue.

The Nine affected Mile Pointprojects 2, Grandare, Gulf 1 & 2, Clinton 1 & 2, Perry 1 & 2, RiverIima -

Bend 1 & 2, Hartsville A1, A2, 81, & B2, Phipps Bend 1 & 2, Skagit 1 &

2, Allens Creek, and Black Fox 1 & 2.

General Electric will inform the affected utilities of the defect and advise them of the corrective action.

j- t

%.<-Glenn G. Sherwood, Manager Safety & Licensing Operation .

GGS:lm/1340 o Attachment cc: Mr. J. F. McAllister .

Mr. U. Potapovs, RRC Region IV -

So 1234 008 l - - -

z _ _ ._

(I )

PGCC Flexible Conduit Grounding

~

Flexible conduit is used to enclose electrical conductors in various fail-safe (deenergize to operate) circuits which are part of the Reactor Protection System (RPS). These include RPS, Nuclear Steam Supply Shutoff System (NSSSS) and Neutron Monitoring System (NMS) logic. One of the purposes of the flexible conduit is to provide a low resistance path to ground under certain short-circuit conditions. This insures that upstream fuses will melt and thereby prevent " hot shorts" which have the potential for preventing the completion of a protective function (de-energizing various circuits). The flexible conduit in question is used on all Power Generation Control Complex (PGCC) installations. Specifically, it is flexible conduit that runs from a panel on a specific floor section, is routed in the floor section, and finally is terminated in a termination cabinet at the end of that floor section.

The flexible conduit is contained in PGCC equipment designed and supplied by the Control and Instrumentation Department of the General Electric Company in San Jose, California.

The nature of the defect is the potential loss of solid metallic grounding of the flexible conduit either at the termination cabinet or at the panel. This has the potential for preventing operation of fail-safe (deenergize to operate) logic associated with the Reactor Protection System.

The condition has been observed at the Hanford 2 site. A check of conduit resistance with an ohmmeter indicated essentially zero resistance to ground. However, this is not considered adequate in that the measure-ment does not account for high values of short-circuit current, casual contact grounding of conduit touching panel steel, and long-term oxidation of the conduit surfaces.

In a typical termination cabinet installation the conduit is firmly attached with a locking ring to a termination module. This is an

- acceptable ground connection; however, the termination module is ultimately mounted on a painted (high electrical resistance) surface. There has been no procedure to insure that paint is removed from panel surfaces before termination modules are mounted. There also has been no procedure to check that the termination module makes a low resistance connection to the panel steel.

The corrective action to provide positive grounding of the PGCC conduit.

will be implemented prior to the fuel load of the affected projects.

The schedule for development and issue of procedures to implement tne corrective action will be provided by January 31, 1981.

GGS:lm/1342 12/8/80 l

t

. ,. . . . . - - - , , - ,_y. _ _ . - - -

. , . , _ . . _ _ .. . . - , _ _ _ _ . _ , _ , -_ - .-