ML19309G395
| ML19309G395 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 05/01/1980 |
| From: | DUQUESNE LIGHT CO. |
| To: | |
| Shared Package | |
| ML19309G391 | List: |
| References | |
| NUDOCS 8005060250 | |
| Download: ML19309G395 (2) | |
Text
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N soso 2jy o FINAL REPORT ON CABLE TRAY GALVANIZING DEFICIENCY G
AT BEAVER VALLEY POWER STATION - UNIT NO. 2 1.
SUMMARY
A number of sharp projections in the cable bearing area of hot dip galvanized safety-related cable tray have been found. These projections are a result of runs and imperfections in the hot dip galvanizing which solidified to form spikes and sharp edges. The cable tray vendor did not adequately inspect and correct cable tray after galvanizing as required by the purchase specifica-tion.
2.
IMMEDIATE ACTION TAKEN All uninstalled trays on site are being inspected for galva-nizing projections prior to installation.
If projections are found, they are filed smooth.
Tray remaining to be shipped is being thoroughly inspected by the Duquesne Light Company in-spectors to ensure no projections exist.
An audit of the Vendor's quality control program is being performed to determine effectiveness.
The Nuclear Regulatory Commission (NRC) was informed that the tray galvanizing was potentially reportable under the provi-sions of 10CFR50.55 (e) (1) (i) on February 7, 1980 by Mr. H. A.
VanWassen of Duquesne Light Company (DLC). AN interim report was subsequently sent to the NRC by DLC on March 10,1980 (signifi-cant deficiency Report No. 80-01).
3.
DEFICIENCY Duquesne Light Company inspectors had, over a period of time, found numerous unacceptable pieces of tray which the cable tray vendor had presented for final inspection.
As a result, the inspectors issued a Nonconformance and Disposition Report iden-tifying the vendor as not adequately inspecting the cable tray.
Inspection of the tray on site was performed and similar defi-ciencies were found.
I 4.
ANALYSIS OF SAFET IMPLICATIONS A.
Galvanizing da iciencies (sharp projections) within the cable bearing. :ea of the cable tray may damage the cable in two waya:
(1)
Tearing cable jacket and insulation during instal-lation of cable.
(2)
Penetrating the cable jacket and insulation sometime during the life of the plant.
f
. B.
We have reviewed each of the above as follows:
(1)
Effect of damaging cable during installation:
A test was conducted to determine the effect of pulling cable over the sharp projections.
Test specimens selected were cables which represent the thinnest jacketed cable purchased and the tray with the worst projections selected from a sample inspection of Cate-gory I cable tray.
The cable was dragged over the projections in a manner to create considerable down-ward force. The results showed that if a projection was sharp at the beginning of a pull it became dull shortly after and that no significant damage to the jacket occurred for the samples tested.
The variation of projections encountered, however, precludes the use of sample testing techniques to demonstrate acceptability for all possible cases.
The results were, therefore, determined to be inconclusive.
(2)
Effect of cable resting on a sharp projection during the plant life,:
To simulate this condition effectively would be im-i practical. Some of the parameters that must be evalu-ated include the weight on the cable., cable aging, temperature of cable, size and configuration of pro-jecticas and time.
We cannot with any degree of certainty state that none cf the projections of many different sizes and shapes found in Category I trays would penetrate through the cable during the plant life.
Sharp projections have been found that measure in height equal to or greater than combined cable jacket and insulation thickness.
(3)
If a protrusion were to penetrate the cable insulation and jacket, a circuit ground of short circuit could result which might not be detectable.
This, in con-junction with a single failure on the redundant equip-ment, could result in an unavailability of both safety systems.
Based on the above we conclude that a potential safety hazard would be possible had this deficiency gone unnoticed.
5.
CORECTIVE ACTION TO REMEDY DEFICIENCY t
l l
Immediate action of inspecting tray before installation will be continued until all tray is installed. Duquesne inspectors will thoroughly inspect all tray.until confidence in the vendor's inspection program has been developed.
All installed safety related tray will'be inspected and deficiences will be corrected or tray replaced before cable is pulled, thus eliminating any safety hazard associated with this deficiency.
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