ML20010C934
| ML20010C934 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 08/10/1981 |
| From: | Koch L ILLINOIS POWER CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, U-0271, U-271, NUDOCS 8108210235 | |
| Download: ML20010C934 (3) | |
Text
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1605-L ILLIN0/S POWER COMPANY 7 g g9g_39y_L 500 SOUTH 27TH STREET, DECATUR, ILLINOIS 62525 August 10, 1981 Mr. James G. Keppler x'
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Director, Region III o
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U.S. Nuclear Regulatory Commission 799 Roosevelt Road
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Dear Mr. Keppler:
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Clinton Power Station Unit 1 Docket No. 50-461/CPPR-137 Reportable Deficiency 80-01 Our le'-:.cr c# February 26, 1980 notified you of a reportable deficiency under the requirements of 10 CFR 50.55(e) concerning l
dcEective plugwelds on swinging dividers for PGCC termination l
cabinets.
A subsequent letter dated September 22, 1980 was submitted as an interim report.
This letter is being submitted as the final report concerning the subject deficiency.
1.
Statement of Reportable Deficiency l
On-site receipt inspection of the control room l
termination cabinets revealed that some of the attachment welds of the swing barriers dividing the cabinets into bays had failed during shipment.
I 2.
Investigation Results As previously reported to the NRC, during the receipt inspection of the Power Generation Control Complex (PGCC) termination cabinets, it was discovered that one l
of the swing barriers in each of three (3) f the twenty-one (21) cabinets had separated from the hinge l
attaching it to the cabinet frame.
The design drawing l
for the barrier specifies plug or spot welds on four inch (4") centers for the full lengt'. of the hinge at tachn. nt.
The manufacturer, (Hogan Manufacturing Company), had selected the plug weld alternative which, in these three cases, resulted in separation failure during shipment.
Subsequent investigation revealed that the welds had failed due to lack of fusion and
-M g that some plug welds on other barriers were also 5 j unacceptable for the same reason.
j/o 810821023S 810810 PDR ADOCK 05000461 S
PDR AUG 18 1981
Mr. J.G. Keppler Page 2 August 10, 1981 3.
Corrective Action i
l Nonconformance Report NCR 2968 was writsen documenting this problem and submitted to General Electric (GE) for dispositioning.
GE dispositioned the NCR such that i
repairs are to be made per FDDR LH1-508-80 R/3.
As l
reported in my September 22, 1980 letter to the l
Commission, the swing barriers were removed from all cabinets in preparation for repair at an off-site l
repair facility.
Since installation of field cables l
was facilitated by the absence of these barriers, it i
was decided to leave them out until most of the work was done.
In order to avoid any reoccurrence of this problem, all the termination swing barriers for s 'S j
were scheduled for reworking even though some may not l
have needed repair.
Since my last letter of September i
22, 1980, NCR 4547 was written recommending that repairs be made on-site by the contractor.
A program has been developed for the repair of the barriers at Clinton Power. Station which will be implemented in the l
coming months.
l 4.
Safety Implications / Significance t
As previously discussed in my earlier letter of September 22, 1980 to the Commission, it is believed that these swing barriers failed during transit to the Clinton Power Station.
The actual loading conditions imposed on the barriers is not known and it would be impracticable to attempt to quantify the loads which L
were imposed.
It can be assumed, however, that if the l
condition had gone undetected, it is possible that one or more swing barriers could have separated from the l
l hinge attachment during a severe seismic event.
If r l
swing barrier came completely loose from its hinge, it would most probably fall to the side, possibly coming to rest against terminal blocks at its upper end.
Although barrier-type terminal blocks are employed in the design, it ic possible that the impact of the fclling panel on the terminal blocks could sufficiently l
damage the separation barriers between terminals to l
short circuit some of the wiring, which could include critical circuitry in one safety division.
If more than one failure occurred and the failure followed the same course and caused the same damage to the circuitry in another safety division, the ability of the plant to shut down or to be maintained in a safety shut-down condition could have been compromised.
Since the repair of the swing barriers does not have any impact on other control room installation work, the planned repair will be performed as time permits during the final months of 1981 or early 1982. Therefore we are submitting this as a 1
Mr. J.G. Keppler Page 3 August 10, 1981 final report in accordance with 10 CFR 50.55(e), and trust that it is sufficient for your analysis and evaluation of the defi-ciency and Corrective Action.
Sincerely,
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. Koch Vice President AJB/prh cc:
H.ll. Livermore, NRC Resident Inspector Director, Office of I&E, USNRC, Washington, DC 20013 i
Director-Quality Assurance l
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