ML17138B442
| ML17138B442 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 07/24/1980 |
| From: | Robert Carlson NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Curtis N PENNSYLVANIA POWER & LIGHT CO. |
| References | |
| NUDOCS 8008270184 | |
| Download: ML17138B442 (5) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION REGION I 631 PARK AVENUE KING OF PRUSSIA, PENNSYLVANIA19406 JUL 24 lSBtj Docket No. 50-387 Pennsylvania Power and Light Company ATTN:
Mr. Norman W. Curtis Vice President Engineering and Construction - Nuclear 2 North Ninth Street Allentown, Pennsylvania 18101 Gentlemen:
Subject Final Report of a Deficiency on PGCC/ACR Electrical Connectors (Your letter of July 8, 1980, PLA-447}
Thank you for your letter, referenced
- above, which forwarded a final report pursuant to 10 CFR 50.55(e) regarding the subject matter.
Your report will be reviewed and evaluated, and should we require additional information concerning 'this matter, we will contact you.
Your cooperation with us is appreciated.
Si neer e1 y,
~y.l R. T. Garison, Chief Reactor Construction and Engineering Support Branch cc:
A.
R. Sabol,
- Manager, Nuclear guality Assurance M.
E. Barberich, Licensing Engineer S.
H. Cantone, Superintendent of Plant
'1<04 f Q
TWO NORTH NINTH STREET, ALLENTOWN, PA.
18101 PHONE: (215) 821-5151 NORMAN W. CURTIS Vice President-Engineering
& Construction 821-5381 July 8, 1980 Mr. Boyce H. Grier Director, Region I U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pennsylvania 19406 SUSQUEHANNA STEAM ELECTRIC STATION FINAL REPORT OF A DEFICIENCY ON PGCC/ACR ELECTRICAL CONNECTORS ERs 100450/100508 FILE 840-4/900-10 PLA-506
Reference:
PLA-447 dated 2/1/80
Dear Mr. Grier:
This letter serves to provide the Commission with a final report of a deficiency on Power Generation Control Complex/Advanced Control Room (PGCC/ACR) panel connectors originally reported in the referenced letter.
The information is furnished in fulfillment of our obligations under the provisions of 10CFR50.55(e).
The attachment to this letter describes the deficient condition along with its safety implications and the corrective action being taken to achieve resolution.
We trust the Commission will find the information forwarded by this letter to be satisfactory.
Very truly yours, N.
W. Curtis Vice President-Engineering
& Construction-Nuclear Attachment ARS:jmk PENNSYLVANIA POWER LIGHT COMPANY
Mr. Boyce H. Grier July 8, 1980 cc:
Mr. Victor Stello (15)
Director-Office of Inspection 6 Enforcement U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Mr. G. McDonald, Director Office of Management Information
& Program Control U. S. Nuclear Regulatory Commission Washington, D.C.
20555 Mr. Robert M. Gallo U. S. Nuclear Regulatory Commission P.O.
Box 52
'hickshinny, Pennsylvania 18655
Attachment to PLA-50 FINAL REPORT ON PGCC/ACR PANEL CONNECTORS DESCRIPTION Wh9.1e implementing PDDR-KR1-506 (rework of termination cabinets),
damaged insulation (cuts, knicks, shield solder connections, etc.)
was discovered on the jumper wires connecting the field wiring terminal board to the cable connector in GE's T-Mods.
This was reported in NCR-3030.
Subsecpxently, similar insulation damage and deficient'pin crimps were discovered in the PGCC/ACR panel connectors.
This was reported in NCR-3403.
A sample inspection program was implemented to determine the extent of insulation damage and deficient pin crimps.
A visual inspection (extracting all pins) and pull test of all conductors and pins was.
performed within each of 250 sample panel connectors.
125 connectors in the ACR inner ring panels and 125 connectors in the relay and back row panels of Unit 1 were randomly selected for the sample.
The sample sizes identified were based on MZL-STD-105D, 29 April 1963, Table I General Inspection Level II and Table ZZA Single Sampling Plans for Normal Inspection.
The sample plan was based on a 0.65 percent AQL acceptance rate.
The sample inspection determined that the Unit 1 ACR inner ring/relay/back row panel connectors did not meet a 0.65 percent QAL for insulation damage and deficient crimps.
CAUSE The causes of the problems could not be positively identified.
- However, it is believed that the damage to the insulation,.consisting of nicks, cuts and abrasions, was caused during the pin insertion process.
The edge of the insertion tool can impact the conductor insulation and cause damage under the high forces required to insert pins into the connector dielectric.
The deficient pin crimps could have been caused by a combination of manfuacturing personnel error and crimping tool malfunction.
General Electric said that their QA program at the time did not provide for verifying the adeauacy of the crimping tool prior to use each day.
ANALYSIS OP SAFETY IMPLICATIONS The PGCC/ACR panel connectors do have safety-related control and instrumen-tation circuits.
Zt is conceivable that improper'ly crimped pins could prevent circuits from performing their design safety-related functions.
Also, damaged insulation, if uncorrected, could permit shorting or intro-duction of external voltage sources into safety-related circuits which could prevent the circuits from performing the designed safety function.
r.
Attachment to PLA-506 (cont'd)
Since damaged panel connectors a
e a random occurrence and could occur in any safety-related circuit, the possibility of a failure exists.
The simultaneous degradation and loss of safety-related circuits could result in a safety hazard to the operation of the plant.
Project Engineering has determined the PGCC/ACR panel connector deficiencies to be reportable under 10 CFR 50.55(e).
CORRECTXVE ACTION GE issued PDX WJIQ, Rev.
0 to initiate a 100 percent visual inspection and pull test of all Unit 1 inner ring/relay/back row panel connectors with No.
20 AWG wire.
PDX WJXQ, Rev.
1 was later issued and expanded the 100 percent inspection to all Unit 1 inner zing/relay/back row panel connectors.
The inspect'on, repair/rework and testing for Unit 1 are 95 percent complete.
The remaining five percent will be completed and tracked by NCR-3403.
Unit 2, will utilize a sampling plan similar to that used for Unit l.
CONCLUSIONS Upon completion of the inspection program, the Unit 1 inner ring/relay/hack row panel connectors will have been subjected to inspection, repair/rework, and testing to assure their functionability and the detection'and repair of defects.
Project Engineering has authorized a sampling plan for Unit 2, and Bechtel Construction and QC will document results and generate an NCR for any discrepancies.