ML20092P543

Forwards Second Interim Deficiency Rept Re Butt Splices in Electrical Conductors.Subj Discussed at 840531 Prehearing Conference.Related Correspondence

ML20092P543
Person / Time
Site:	Byron
Issue date:	07/02/1984
From:	Gibbs M COMMONWEALTH EDISON CO., ISHAM, LINCOLN & BEALE
To:	Callihan A, Cole R, Smith I Atomic Safety and Licensing Board Panel
References
NUDOCS 8407090075
Download: ML20092P543 (8)

Text

. _ _ _ _ _ - _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - - _ _ _ _ _ _ _ _

Opl) j RELATED CORRESP0doENCE ISHAM, LINCOLN & BEALE COUNSELORSAT ggg U. % )

l THREE FIRST NATIONAL PLAZA CHICAGO. ILUNOl$ 60602 .

]

g 2

RTT CO N.18721as It20C N Av .N W WILLIAM G. BEALE - 1885 1923 Sul'E 840 crn .F M . . **S"%'$8f'*

• is,n;'jjy;r*

.um.

4 July 2, 1984 a

Ivan W. Smith, Chairman Dr. A. Dixon Callihan Administrative Judge Administrative Judge Atomic Safety and' Licensing Board Union Carbide Corporation U.S. Nuclear Regulatory Com- P.O. Box Y mission Oak Ridge, Tennessee 37830 Washington, D.C. 20555 Dr. Richard F. Cole Administrative Judge Atomic Safety and Licensing Board U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Re: In the matter of Commonwealth Edison Company (Byron Nuclear Power Station, Units 1 and 2) Docket Nos. 50-454 and 50-455 .

Dear Administrative Judges:

I am enclosing Commonwealth Edison Company's second interim report regarding-butt splices in electrical conductors at Byron Station, a subject which was addressed at the prehearing conference on May 31, 1984. The final report on this matter will be provided as soon as it is available.

Ve.y truly you s

f\(A l Martha E. Gibbs MEG

mg Encl. - -

8407090075 840702 PDR ADOCK 05000454

[D Commonwealth Edison

>- 1  := ) oni First National Plata. CNcago. Illinois a ' ( O 7 Address Reply to: Post Office Box 767

. j Chicago. Illitiois 60690 -

July 2, 1984 Mr.-James G. Keppler, Regic.1al Administrator Uniteo States NJclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137

Subject:

Byron Generating Station Units 1 and 2

, Electrical Conductor Butt Splices

- -NRC Docket Nos. 50-454 and 50-455 References'(a): May 17, 1984 letter from D. L. Farrar to J. G. Keppler.

I (b): May 25, 1984 letter from R. L. Spessard to Cordell Reed.

(c): June 6,-1984. letter from R. L. Spessard '

to Cordell Reed.

(d): June :2, 1984 letter from T. R. Tramm to J. G. Keppler.

Dear Mr.-Keppler:

This letter provides the second interim report of a deficiency potentially reportable pursuant to 10 CFR 50.55(e) regarding butt splices

~

in electrical conductors at Byron station. A final report is espected to

-be available by July 10,-1984. For tracking purposes, this deficiency is 3

numbered 84-03.

As indicated in the.first interim report submitted in reference (d),:a reinspection program was undertaken in May, 1984 to verify the acceptability of~ crimped butt. splices in electrical conductors. This letter presents an overall summary =of the data accumulated during this reinspection program._ Attachment A to this lists contains the acceptance

. criteria utilized'for the reinspection of both uncovered and' covered butt

' splices. It identifies by unit the quantity.of deficiencies identified forceach criterion. Attachment B to this letter presents our evaluation 1 of the reinspection. data.

During this reinspection, 1,311_ butt splices were-identified on

! . conductors of safety-related cL*eles~on Byron 1 and ?. '747 of these

[  : installed butt splices were fou.id uncovered (i.e.,'without a tape and n ' cement or heat shrink covering). Documented visual inspections were performed cui all 747 splices. "he remaining 564 installed _ butt splices m w ~ ~ ~,e ,. + - , , - ~ ~ - . r. -w - w, w , .-

J. G. Keppler July 2, 1984 identified were found covered with heat shrink material or nuclear cement cnd tape. Their installation location was documented by identifying the cable number on which they were installed, the specific conductors of the cable, and the equipment number of the component in which they were located. Of the 564 covered butt splice installations identj'ied, 92 tere determined to be associated with redundant cables. These 92 butt splices were cut out and had the covering material removed. Documented vjsual inspections were performed on all 92 splices.

A total of 839 butt splices were visually inspected. 65 of these splices are considered unacceptable for various reasons as described in Attachment A. The reject rate is 7.7%, well below the 10%

threshhold established in reference (a) for expansion of the reinspection program. The visual inspection work has therefore been terminated.

In general, it appears that the butt splice installation discrepanties observed are relatively minor. The spliced conductor would probably have performed satisfactorily for the life of the plant. The potential safety significance of all defects will, however, be deter"ined. This work is now in progress and tha results will be rer orted in the final report on this discrepancy.

This is still considered to be a discrepancy which is potentially reportable pursuant to 50.55(e). The final determination of reportability_cannot be made until the engineering evaluations have been made to determine if these butt splice deficiencies could have adversely af fected the safety of plant operations if they had not been detected.

As identified in reference (b), the implementation of this reinspection program has been under constant surveillance at Byron by Region III electrical inspectors.

Very truly yours, f fQ fg=s= -

T.R. Tramm Nuclear Licensing Administrator im Att:chment 8899N

k ATTACHMENT A Deficiarcies Identified in Electrical Butt Splices There was a total of 747 uncovered butt splices identified during the program which were visually inspecteJ. Of these, 653 on Unit 1 ar.d 31 on Unit 2 were determined to be acceptable. All 747 butt splices were inspected per the criteria in Table A-1 below. This table identifies by criterion the quantity of deficiencies identified on each unit during the reinspection program for uncovered butt splice installations.

TABLE A-1 Acceptance Criteria For Installed Butt Splices UNCOVERED Deficiencies Unit Unit Criterion 1 2

1. The butt splice installed appea.s to have been crimped with the proper tool. 2 0

2. The butt splice installed is the proper size for the size of cable it is installed on. 0 0

3. The conductor crimp is approxiately centered on the wire barrel. 11 0

4. The end of the conductor is visible beyond the point of crimp. 47 4

5. The conductor insulation is approximately flush with or under the insulating sleeve of the butt splice. 0 0 Total Deficiencies' Identified: 60 4 Note: 1 butt splice was d=ficient for both criteria 3 & 4, so there were 64 desiciencies on 63 splices.

Attachment A There was a total of 92 covered butt splices identified during the program which required the removal of the covering material so that a visual-inspection could be performed. Of these, 90 were determined to be acceptable. All 92 of these butt splices were arsociated with Unit 1 cables, and they were all inspected per the criteria in Tabla A-2 below.

This table identifies by criterion the quantity of deficiencies identified on each unit during the reinspection program for covered butt splice installations.

TABLE A-2 Acceptance Criteria For Installed Butt Splices COVERED Deficiencies Unit Unit Criterion 1 2

1. The butt splice installed appehrs lo have been crimped with the proper tool. 0 0

2. The butt splice installed is the proper size for the size of cable it is installed on. 0 0

3. The conductor crimp is approximately centered on the wire barrel. 2 0

4. The end of the conductor is visible beyond the point of crimp. 0 0 2 ~G~

Note: The covering on these splices made it unnecessary to impose any acceptance criterion on the conductor insulation, as was dune for uncovered splices.

8899N 1

l l

j

I b

ATTACHMENT B

, l Evaluation of Butt Splice Reinspection Data PROGRAM The butt splice reinspection program consisteo of the inspection and documentation of previously installed butt splices on conductors nf safety-related control and instrumentation cables located in cafety-related panels, switchgear, motor control canters and both sides of electrical penetrations. The four uasic phases of this reinspection program were:

1. Inspect the butt splices which were found to be uncovered and document the results of these inspections.

2. Document the installation location (i.e. equipment, cable and cable conductors) of butt splices found which were covered with hwat shrink material or nuclear cement and tape.

3. For any redundant cables identified in item 2 above, remove the butt splice (s) installed on one of the cables, remove the covering material and document the inspection concerning the condition of the butt splice as it was found to be installed.

4. Accumulate the results of items 1 and 2 above and determine the overall inspection rate for installed butt splices. If the rejection rate for the overall program was greater than 10%,

then all remaining butt splices identified in item 2 above *culd be required to be reinspected or replaced.

The inspection activities associated with this reinspection program identified .,311 butt splices installed on approximately 454 safety related cables associated with Byron Units 1 and 2. For this reinspection effort, 7,246 safety-related cable ends were documented as having been inspected. The inspection documents and the butt splices chich were removed and dissected are all on file.

9 u

Attachment B 1

RESULTS l The tabulation of the results of this butt splice inspection as <

it relates to these four phases of the program are: I l

1

1. Uncovered Butt Splices The total quantity of uncovered butt splices identified and reinspected ,

was 747.

a) Quantity rejected by the initial inspector 275 b) Quantity found acceptable by 2nd inspector after dissection 16 c) Quantity founu acceptable based on manufacturer's documented test data 196 Total Acceptable After Dissection 212 d) Quantity rejected for inspection criterion (1) 2 e) Quantity rejected for inspection crtierion (3) 10 f) Quantity rejected for inspection criterion (4) 51 Total Rejected After Dissection 63 Total Dissected Butt Splices 2DT The accumulated results for uncovered butt splices inspected, therefore, yielos 63 rejectable butt splices identified out of a total of 747 Inspected.

In reference to item 1.(a) above, the butt splices which were initially inspected in the plant and found rejected, were cut out and tagged to identify the cable and the conductors on which they were found. These butt-splices were then brought into the office and dissected and reinspected by a second QC inspector. This inspection was documented and attached to the original inspector's inspection report (see item 1.(b)]. This was done because the conditions surrounding installed butt splices did not always allow easy accessibility for reinspection.

2. Covered Butt Splices A total quantity of 564 covered butt splices have been identified and their-installation location has been documented.

3. Redundant Butt Solice Installations Of the 564 covered butt splices identified ir item 2 above, 92 butt splice installattuns were identified as being redundant and required inspection. These butt splices were all cut uut and dissected in the construction of fice with the following result!

• l

^

Attachment B

_3-a) Quantity of covered butt s,11ces removed and 92 dissected b) Quantity found to be acceptable after inspection 16 c) Quantity found to be acceptable based on manufacturer's documented test data 74 Total Acceptable After Dissection 90 d) Quantity rejected for criterion (3) 2 Total rejected after dissection 2 Total covered butt splices dissected and inspected 77

4. Accumulated Results There was a total of 1,311 installed butt splices identified in this program. 747 were found uncovered and were inspected. SoA were found covered with heat shrink material or nuclear cement and tape, and were inspected.

i a) Total. quantity of uncovered butt splices inspected 747 b) Total quantity of covered butt splices dissected and inspected 92 c) Total quantity of butt splices installations inspected in the program 839 d) Total quantity of uncov' red butt splices found rejected 63 e) Total quantity of covered butt splices dissected and found rejected 2 f) Total quantity of butt splice installations inspected and found rejected during the program 65 The rejection rate for the overall program (item f divided by Il item c) is calculated to be 7.7%.

BASIS FOR ACCEPTANCE With reference to items 1.(c) and 3.(c) above, during this butt splice inspection program, installed b"&t splices (size #16-14) were identified which appeared to be crimped with a #22-18 crimping tool rather than the size #16-14 tool. While this tool is not the correct tool for crimping a #16-14 size butt splice / wire, it is, an acceptable

(" proper") crimping tool for butt splice installation. Tests on such splices by the manufacturer and at Byron station indicate that the #22-18 tool makes crimps in #16-14 butt splices which are in all respects Occeptable and in some respects superior to those produced with the size

1. 16-14 tool. After evaluation of these test results, previously 1 1...colled butt splices which were identified to have oeen crimped with the #22-18 crimping tool were considered to be acceptable and items of this nature previously reported were removed from the deficiency j

population.

8899N