ML19256F139

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Second Interim Deficiency Rept Re Electrical Cable Tray Hangers W/Light Partial Penetration Welds Where Full Penetration Welds Required.Caused by Incorrect Interpretation of Weld Symbols.Weld Procedure Revised
ML19256F139
Person / Time
Site: Comanche Peak  Luminant icon.png
Issue date: 11/14/1979
From:
TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:
Shared Package
ML19256F135 List:
References
NUDOCS 7911210474
Download: ML19256F139 (2)


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TXX-3067 Attachment November 14, 1979 Page 1 ELF TRICAL CABLE TRAY HANGERS Description of the Deficiency The prime contractor subcontracted with Chicago Bridge & Iron to shop fabricate cable tray hangers on site. At the time the deficiency was identified, CB&I had been assigned four hundred four (404) designs. The hanger weld details required full-penetration single groove welds. Cable tray hangers that were fabricated and inspected by CB&I and accepted by the licensee were found to have light partial penetration welds where full penetration single groove welds ,.ere required by the designer. This deficiency resulted from an incorrect interpretation of weld symbols by CB&I.

Analysis of Safety Implications The cable tray hangers are the support system for the cable tray raceway carrying cables which include Class IE circuits. These hangers were designed to resist the maximum loading combination, including a Safe Shutdown Earthquake. Had these defective welds gone undetected after installation of the cable tray supports, it is conceivable that the cable tray supports would have been over-stressed under maximum loading condi-tions.

Corrective Actions The following actions have been taken to correct the weld deficiencies identified with CB&I hanger fabrication activities:

1. The four hundred four (404) cable tray hangers assigned to CB&I were identified and dispositioned by engineering. The dispositions are categorized as follows:
a. 19 hangers were accepted "as-is" because no groove welds were required by the drawings.
b. 120 hangers were accepted "as-is" because the installation method requires that the groove weld be a field weld which is made by the prime contractor and not CB&I.

15!/ 195 7 911210 '-f- 74

TXX-3067 Attachment November 14, 1979 Page 2

c. 19 hangers were voided because they were no longer necessary.
d. 34 hangers were voided because they were replaced by new hanger designs to conform to field conditions.
e. 2 hangers were refabricated to conform to the design drawing.
f. 210 hangers are in the process of being reworked per engineering direction to bring them in full compliance with all engineering requirements.
2. To preclude recurrence of this problem, CB&I weld procedure GWPS-SMAWX REV. I has been modified to provide additional technique information to the welders for this weld type. In addition, all CB&I welders and inspectors have been reinstructed in the requirements of weld symbols, proper weld technique for a full penetration single groove weld, and in the drawing requirements.

13// i96

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