IR 05000289/1975005
| ML19256D624 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 03/21/1975 |
| From: | Gage L, Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML19256D623 | List: |
| References | |
| 50-289-75-05, 50-289-75-5, NUDOCS 7910190581 | |
| Download: ML19256D624 (6) | |
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S. :'UCLE/R' REGU:liTORY CO:0:ISSIO::
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0FFICE OF I::SPECTIO:: A!!D E::FORCDIE :T E'.
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REGIO:1 I IE Inspection Report 2:o: 50-2S9/75-05 Docket No: 50-259
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Licensee: ?fetro' olitan Edirnn Connanv License Mo: DPR-F'
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O. Box 542 Priority:
Itqadi c. Pennsv1vanin 19603 Category:
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Safeguards Group:
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Location: Ifiddlet own. Pennsv1vania (Three ? tile Island 1)
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Type cf Licensee:
TW, 871 INe (B!.U)
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T" e of Inspectien:
Snecial, Announced Dr
,of Inspection: March 11, 1975
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Darns of Previous Inspection:
February 24-27. 1975
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Reporting Inspector:
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pt,L. W. Gage, Reactor Inspector DATE Accompanying Inspectors:
None DlTE DATE
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DATE Other Accer * 'ing Personnel:
None DATE
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' a enes. fenior Reactor Im.etor DA!!
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.547 991o290 5 7 /
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Enforecnent Action C 63 c3
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It c~s o f Noncon,liance g
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None B.
Deviations None
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Licensee Action on Previousiv Identified Enforcenent Itens Not applicable Desien Chances
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None identified
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Unusual Occurrences (Reference Nonroutine 30-Day Report No. 75-01)
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The referenced report, transmitted by the licensee to 0IE:I via letter No. GQL 0791, dated F,ebruary 24, 1975, described a trip of the resting-house D3-50 feeder breaker.
The trip vas attributed to a viring fault in the Emergency Lighting Panel CT-1 Circuit of the I-T-E Inperial 1B 1:ngineered Safe,quards Motor Control Center.
The fault uas traced to a wire (in the CT-1 circuit, between the DB-50 feeder breaker and an M0 30 circuit breaker) that burned out and opened.
Other Sienificant Findines A.
Current Findings Unresolved Iten - Desien and Consa acti~on of ES '!otor Control Centers The licensee has initiated corrective action to preclude a repeti-
-:an of the failure that occurred in the 1D Engineered Safeguard's tor Control Center.
They are revieving the architect-engineer's
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ecification for the design of the notor control centers, and thev intend to inspect the vendor's ucrkr.anship in the fabrication of the no ter control center 7.
uits ::c w consi.iere: to be unrecclved.
(Det,'Is, Pararrc-.'O 1451 348'
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Stntus o' Prev 6uel' %,n r re:' I'nrcFolved Ite.s
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!5nacenent In t ervic'.?
At the conclusion of the inspection, the inspector held a neecing at the site uith the follouing personnel to discuss the inspection findings:
- letronolitan Edison Cornanv Mr. J. Colit, Unit 1 Superintendent
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Mr.
C. Eart=an, Unit 1 Lead Electrical Engineer The follouing itens vere discussed, and the inspector's findings were ackn.1redged by the licensee:
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Purnose of the Insnection The inspector stated thet the purpose of this special, announced inspection ras to examine the 1B Engineered Safeguardo Motor Con-trol Center that was the subj ect of the licensee's nonroutine 30-day report number 75-01.
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Current Findines.- Unresolved It er.s The inspector stated that the following item was obser' ed and is considered to be unresolved:
Desinn and Construction of ES Motor Control Centers The licensee has initiated corrective action to preclude a repeti-tion of the failure that occurred in the 1B Engineered Safeguards *
Motor Control Center.
They are reviewing the architect-engi cer's specification for the design of the motor control centers, and they intend to inspect the. vendor's worknanship in the fabrication of the notor control centers.
(Details, Paragraph 2)
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DETAILS r -(]_g
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Persons Contacted Metrorolitan Edison Co nanv
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Mr. C. ilartman, Unit 1 Lead Electrical Engineer
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I-T-E Innerial Corocration Mr. J. Day, Harrisburg, Pennsylvania Area Representative (via telephone)
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Desien and Control of ES "otor Control Centers The inspector reviewed the architect-2ngineer's specification for the design of the Engineered Safeguards (ES) Motor Control Centers and the corresponding purchase order.
The specification is titled
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" Lou Voltage Motor and Fe. icr Distribution Equipnent--TMI Nuclear Station-Unit 1" and is further identified as GAI M.0. No. 4192, associated with purchase order nunber 40017.
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the specification references drauing number B-201-044 fer the 1B ES s
I Motor Control Center.
The inspector reviewed the lacest revision (Revisica "o.
17) of the draving.
It lists the ecuf pnent (and it s electrical ratings) in each nodule in the notor control center.
It does not list the interconnecting wires in each nodule.
The only reference to interconnecting wires appears in the specification, en sheet 14, in a paragraph titled, "Terninal Block and Control Wirin;."
The paragraph states, in part:
"All secondary and control wiring shall be 600 V. No.12 AWG minitun size, stranded copper switchboard wire uith Vulkene SIS type insulation."
The specification does not address power viring to the circuit breakers.
The licensee stated that the wire that burned and opened (discovered on January 24, 1975 and described in their nonroutine 30-day report ho. 75-01) was a "o. 14 vire in Module 4FL.
This is in the Enertenc.-
Lighting Panel CT-1 circuit.
This uire was connected bttreen an 30 circuit breaker (30-anpere rating) in 'todule 4FL and one of
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e breaher's associated bus stabs on the 1000-annere bus in the IB
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tar Control Center.
The 1000-arpere bus is connected to the DE-30
- z feeder breaker that trippe.d and initiated the nonrcutine report.
The licenree providcu the irmector *.-ith a " ire identified ar the
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Mien thO iPP"C;t'r and CIO liC'eniC O
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checi cd the diarcter of the. wire, t! cy found that it uns a thic'ccr,
No. 12 wire; not the 50. 14 ufre that it cas identi~bd es.
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en -a The licensee then stated that, subs 4,uent to discoverint t! a burned No.14 uire in the Energenc:. hir,hting Panel circuit. a second burned uire cas discovered in another nodule.
This uire vas in the Diesel Generator South Supply Fan AFZ-293 circuit.
The licensee reidenti-ficd the rire in cuestion as the rire in the ARE-20?, circuit.
This uire uas connected betucen an MO 50 circuit breaker (50-annere rating)
and one of the breaker's associated bus stabs on tha 1000-anpere bus.
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The licensee stated that all the circuits (approxinctcly fifty of then) in the 13 Motor Control Center feed off this 1000-annere bus ~,
and both vires probably failed at the sane time.
When the vires
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burned and opened, their unsupported lengths dropped touards grounded surfaces, which in turn caused the DB-50 breaker to trip.
The inspector e::anined the No.12 wire. The insulation was not burned or charred.
At the point a t which the uire burned open, the seven strands of conductor were fused together.
The wire is rated for 40*C anbient terrperature plus a 50*C tempera-ture rise.
All ecuipnent in the notor control centers are cualified
'S for continuous duty at 60*C.
The MO 30 and MO 50 circuit breakers
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are thornal-nagre, tic units. The licensee stated that they cannot be adjusted in the field and that there is no r.ditional current overload protection in their circuit branches.
The inspector revieued the licensee's Change / Modification Requests
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Nos. 235 (dated January 29,1975) and 242 (dated February 5,1975).
Request No. 235 reconnends, as a tenporary and innediate fix, re-placing the burned wires with No. 8 uire.
It uas approved and aug-nented by the licensee.
Reauest No. 242 reconnends, as a long-range progran, inspecting all interconnecting uires in the seven notor control centers supplied by I-T-E Inperial and replacing those that do not nect certain reconnended wire sizes.
The recon-nended wire sizes are calculated on the basis of the current rat-ings of the circuit breakers that they are connected to, plus an additional saf ety targin.
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quest No. 235 irdicated that several similar uire-fcilure problens
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rc c::rcrienced by the licensec during preoperational chechout.
L.c licensee stated that sene of these failurcs ucre caused by leose connections at tFc cire lugs.
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The l icensee s ta t c _ tbat they bave initiated cerrc;tj a c.ctien en Mt.
' a rP"Ctj!.icn Of t!.c Wirc ~ !iiMr0G i n t he ~ ~' ;m J O ".. rr 1 s
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acnters.
They are revic.in? the architect-ennincer's spec ifica ric-for the design of the centcrs in conjunctica '..ith tPc recer-erde.ti.
s in Chan:c Tcouest ::o. 242, and they interd te inspect the vendor's teorkrianship in the f abrication of the centers.
This item is considered to be unresolved, pending a subsecuent revic.-
by an ::1C inspector of the licensee's corrective action.
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