ML20101G416
| ML20101G416 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 12/17/1984 |
| From: | Woolever E DUQUESNE LIGHT CO. |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| 2NRC-4-208, 84-07, 84-7, NUDOCS 8412270502 | |
| Download: ML20101G416 (7) | |
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2NRC-4-208 (412)787 - 5141 Telecopy 29 Nuclear Construction Division December 17, 1984 Robinson Plaza, Building 2. Suite 210 Pittsburgh, PA 15205 United States Nuclear Regulatory Commission Region 1 631 Park Avenue King of Prussia, PA 19406 ATTENTION:
Dr. Thomas E. Murley Administrator
SUBJECT:
Beaver Valley Power Station - Unit No. 2 Docket No. 50-412 Power Conversion Products, Inc.
Potential Significant Deficiency Report 84-07 Gentlemen:
This final report is in reference to the Potentially Reportable Significant Deficiency relating to the voltage regulators supplied by Power Conversion Products, Inc.
Pursuant to the requirements of 10CFR50.55(e), it is anticipated that no additional reports will be submitted to Region I.
DUQUESNE LIGHT COMPANY By E. J. Woolever Vice President JS/wjs Attachment Mr. R. DeYoung, Director (3) (w/a) cc:
Mr. B. K. Singh, Project Manager (w/a)
Mr. G. Walton, NRC Resident Inspector (w/a)
INPO Records Center (w/a)
NRC Document Control Desk (w/a)
SUBSCRIBED AND SWORN TO BEFORE ME'THIS
/7d/ DAY OF gjmjw
, 1984 Yt MNt d lbL h[9 Notary Public ANITA ELAINE REITER, fICTARY PUBUC POSINSON TOWN 5H!P, ALLEGHENY CCJ, TY 8412270502 841217 MY COMMISS!CN EXPIRES OCT00 Eft 20,1906 ll PDR ADOCK 05000412 PDR g
United Stcteo Nuclect Rsgulttory Commiosien Dr.=Thom a E. Murlsy-Page 2 COMMONWEALTH OF PENNSYLVANIA )
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- COUNTY OF ALLEGHENY
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On this
/ f/I day of
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, before me, a Notary ' Public in and for said Commonwealth and County, personally appeared E.
J. Woolever, dio being duly sworn, deposed and said that (1) he is Vice President of Duquesne - Light, (2) he is duly authorized to execute and file the foregoing Submittal on behalf of said Company, and (3) the statements set forth in the Submittal are true and correct to the best of his knowledge.
1c d Notary Public ANITA ELAINE REITER, NOTARY PUBLIC ROBINSON TOWNSHIP, ALLEGHENY COUNTY MY COMMISSION EXPlRES OCTOBER 20,1986 I
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f BEAVER VALLEY POWER STATION - UNIT NO. 2 m
DUQUESNE LIGHT (DMPANY t
Potential Significan.t Deficiency Report 84-07.
-Voltage Regulators Supplied by Power Conversion Products, Inc.
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SUMMARY
- A limited-inspection of the voltage regulators supplied by Power Conver-sion. Products, Inc., (PCP) ' under Purchase Order 2BV-337 was performed by Beaver Valley Power Station Unit '2's (BVPS-2) Site Quality Control Group (SQC).
This inspection resulted in identifying potentially significant
~ deficiencies. in internal wiring workmanship. An evaluation has been performed E to determine the specific safety significance of this issue.
These evaluations as described in Section 4 indicate-that none of the
. poor wiring workmanship items noted could have resulted in-a reportable condition.
4 2.
IMMEDIATE ACTION TAKEN On August 10, 1984, Mr. Hall, Acting Manager of Duquesne Light Company's Regulatory Affairs Department, notified Mr..G.
Meyer of the NRC Region I Office of this potentially significant deficiency..
The subject PCP equipment was incorporated into a 100% inspection / repair - program - for Class 1E electrical equipment. Refer to Section 5, " CORRECTIVE ACTION 10 REMEDY DEFICIENCY."
The initial report, 2NRC-4-142, wa s submitted September 14, 1984; and the interim report, 2 NRC-4-169, was submitted to Region I on October 15,
1984.
3.
DESCRIPTION OF THE DEFICIENC_Y Specific instances of poor wiring workmanship that were noted by SQC included:
a) problems with crimping practices b) broken conductor strands c) unauthorized use of solder d) nicked and gouged insulation on conductors e) incorrect type of connectors f) excessive tension on conductors g) improper use of splice connectors l
4.
ANALYSIS OF SAFETY IMPLICATION Of the observed deficient conditions, instances of improperly crimped conductors were the most numerous.
If one of the improperly crimped wires were to ' detach from its lug under vibratory seismic loadings, a loss ~ of function for the voltage regulators could result.
Conductors with an excessive number of broken strands or damaged insulation could likewise cause a loss.of regulator function under ' seismic - loadings.
Thus, the above deficient condit ions were ' initially judged to have the potential ' to cause the loss of Class IE voltage regulators during a seismic event and/or prolonged exposure to the natural frequencies
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- experienced ' during normal operation of the. equipment.
In _ addition to
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. regulating the voltage to the required loads, the PCP equipment functions as Class IE isolation devices. The loss of either this isolation function or. the ability to deliver power to downstream Class IE loads, coupled
-with a single f ailure of a redundant vital bus or isolating transformer, could adversely impact. the capability of the plant to safely shutdown under certain accident conditions.
3-Subsequently, the detailed evaluations and reinspections of each of the specific ~ instances of poor wiring workmanship lis ted in Section 3 indicate that. no potent ially significant deficiencies, existed which, if left uncorrected, could have advers ely impacted the safe operations of the plant.
.This conclusion is substantiated ~ as follows:
The wiring workmanship within each of the six BVPS-2 voltage regulators _ supplied under 2BV-337_ was analyzed in de tail..
The summaries below provide the evaluation and disposition for 'esch of the. reported types of poor workmanship, a) Pr_oblems with crimping practices There were two generic problems reported with crimping practices.
The first reported problem with crimping ' practices concerned the use of a lug which was believed to be the incorrect type.
Some of the lugs had insulation trapped under the crimp.
The lhgs were split-barrel type versus the solid-barrel type normally speci fied.
These lugs were applied only to solid conductors used in the magnetic circuits within the PCP voltage regulators.
It was determined that the vendor (PCP) selected terminal lugs specifically designed for crimping solid conductors (Thomas & Betts " dragon tooth" lugs).
These lugs are insulation penetrating (do not require removal of conductor insulation) and are specifically designed for magnet wire te rmina-tions. These lugs were sized and selected according to the recommenda-tions of the manufacturer (Thomas & Betts).
Also, the lugs were crimped and inspected according to PCP procedures which incorporated the tensile tests described in the applicable wiring standard, Under-writers' Labaratory Specification UL-486-A.
Therefore, based on the above, no defleiencies or workmanship problems exist with the use of Thomas & Betts " dragon tooth" lugs on solid conductors.
The second reported problem concerned crimps of stranded conductors on Burndy lugs which appeared not to be centered on the lug barrels, nonuniform crimps, distorted lug barrels, and crimps with the conduc-tor not visible in the inspection hole.
Various ' evaluations were 4
perfo rmed regarding the observed conditions.
Visual ins pect ion and pulling on each of the conductors indicated that the conductors were adequately captured within the crimp.
Based on these activities, the subject crimps and terminations were judged as capable of performing their intended safety functions under all applicable ' loading conditions.
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b) Broken c_onductor strands _
Several instances were found where conductors were partially cut or n icked, and conductor strands were broke n.
These specific problems were examined; and, in six instances, the conductor damage did not meet the accept ance criteria contained in the BVPS-2 Electrical Installation Specification 2BVS-931.
However, subsequent evaluations of each of these deficiencies indicate that the reduced conducto r capacity, due to the conductor damage, would not have resulted in any unsafe electrical conditions.
c) Unauthorized use of solder Unauthorized or improper use of solder was reported as an instance of poor wiring workmanship.
Specifically, solder was used on the choke soil le ad connect ions for the 5-kVA PCP voltage regulators.
A PCP standard procedure for terminating solid square wires in magnetic circuits is to use a soldered-end-crimp connection. The solder provi-sion, applied in accordance with PCP standard solde ring practices, ensures a good electrical connection, while the crimp ensures a good mechanical connection.
It is PCP's expe rience that this arrangement provides a reliable conne ct ion for magnetic circuits utilizing solid conductors.
An alternative method for making connections to solid square wires is to use ths Thomas & Betts "d r agon tooth" lugs dis-cussed in Section 4.a of this report.
d) Nicked and gouged insulation on c_onductors There were no instances found of nicked or gouged insulation on con-ductors in the PCP voltage regulators.
This poor wiring workmanship item was erroneously identified as existing within the PCP equipment.
e) Incorrect Types of connectors Three generic problems were reported regarding the usage of incorrect types of connectors within the PCP equipment.
The first generic problem with incorrect types of connectors involved 45 terminations where spade-type lugs were used.
Although spade-type lugs are not normally used, these 45 instances involved terminations to capacitor component s which were supplied with connectors that accepted only spade-type lugs.
The use of these lugs was verified as accept able during the seismic qualification testing of the prototype PCP voltage regulators.
Therefore, the use of spade-type lugs in the above applications is not considered a deficiency.
The second generic problem with incorrect types of connectors involved the use of short-barrel lugs in lieu of long-barrel lugs. Long-barrel as a preferred type to provide more space for lugs were specified crimping.
However, short-barrel lugs are acceptable, provided the crimp is applied satisf actorily.
Therefore, the use of short-barrel lugs is not considered a deficiency.
The third generic problem wi;h incorrect types of connectors involved eight instances where stranded wires we re terminated at internal
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circuit breakers by a pressure sc rew-type connection, instead of by the terminal ' lug-type.of connection.
Although the pressure-type of connection is a standard connection assembly supplied by the circuit g'
l breaker manufacturer and is an acceptable connection, these connectors will be replaced by crimped Burndy lugs.
f) E_xcessive tension on conductors There were no instances found of excessive tension on conductors in the PCP voltage regulators. Inspections did, however, identify several instances there wire harnesses within the PCP cabinets were resting over the edges of internal components. These instances were evaluated and will be resolved -in accordance with the rework instructions in 2BVS-931.
g) Improper use of splice connectors Certain internal connections within the magnetic circuitry of the PCP voltage regulators were made with splice connectors, rather than with terminal blocks. Although the use of terminal blocks is the preferred method to make such connections, PCP elected to use splice connectors based on the compact design of the cabinets and the rigidity of the wiring due to the use of solid connectors for the internal magnetic circuitry.
These connection points are not insulated; however, their integrity was verified as acceptable during the seismic qualification of the prototype PCP voltage regulators since no failures occurred.
These splice points will be insulated during the rework. program in accordance with 2BVS-931.
In summary, the evaluations and analyses discussed above indicate that none of the poor wiring workmanship items that were reported for PCP voltage regulators could have resulted, if le f t uncorrected, in any adverse impacts on the safe operations of the plant.
The evaluation included an inspection of the prototype unit at the vendors facility to verify that the units furnished for installation were essentially dupli-cated of the prototype unit.
5.
CORRECTIVE ACTION TO REMEDY DEFICIENCY The inspection / repair program regarding workmanship of internal wiring of vendor supplied Class IE electrical equipment for BVPS-2 is presently in process. Specific wiring workmanship criteria have been incorporated into Specification 2BVS-931, which is the controlling document for electrical equipment installation at BV PS-2.
Although no de ficiencies have been found in the subject PCP equipment which could have caused the equipment to fall, all of the PCP voltage regulators supplied under 2BV-337 are included in the ge neral vendor-supplied Class 1E electrical equipment inspection / repair progema. Thus, through this program, any vendor wiring deviations from the program's inspection criteria will be ide nt if ied,
evaluated, and corrected, if necessary, 'following approved procedures and standards.
For example, the broken conductor strands problem ident ified in 4.b.
will be correct ed in accordance with the rework guidelines in 2BVS-931. This action will further ensure that the subject PCP equipment is capable of performing its intended safety functions.
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The completion of the workmanship inspection / repair progran is scheduled for June 30, 1985.
6.
ADDITIONAL REPORT _S This is the final report regarding the potential significant de ficiency of poor wiring workmanship in PCP voltage regulators.
It is anticipated that no additional reports will be submitted.
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