TXX-6771, Final Deficiency Rept CP-85-50 Re Use of Improper Welding Processes in Mfg of Cable Tray Tee Fittings.Initially Reported on 851206.Acceptable Min Weld for Each Tee Fitting Configuration Identified.Mods Completed by 880301
| ML20235L490 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 09/30/1987 |
| From: | Counsil W, Keeley G TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| CP-85-50, TXX-6771, NUDOCS 8710050486 | |
| Download: ML20235L490 (3) | |
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Log i TXX-6771 m-
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File # 10110 i
908.3
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Ref # 10CFR50.55(e) lllELECTRIC September 30, 1987 Wmiam G. Counsil two.he %s hesident U. S. Nuclear Regulatory Commission Attn:
Document Control Desk Washingsn, D. C. 20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NOS. 50-445 AND 50-446 CABLE TRAY TEE FITTINGS SDAR: CP-85-50 (FINAL REPORT)
Gentlemen:
l On December 6,1985, we verbally notified your Mr. H. S. Phillips of a deficiency involving the use of improper welding processes in the manufacturing of cable tray tee fittings which could affect the seismic qualification of the cable tray system. We have concluded that this deficiency is reportable under the provisions of 10CFR50.55(e) and the required information follows.
DESCRIPTION OF PROBLEM During an engineering review, damaged cable tray " Tee" fittings were noted in a lay-down area. Upon reviewing the " Tee" fitting design documents to establish corrective action repair procedures, welding was observed which was not in accordance with the supplier (T. J. Cope) drawings. Although approved drawings required crossmembers to be welded at the top and bottom at the siderail connection, some members were welded on the top only.
Our evaluation of these conditions determined that inadequate information provided in the Vendor drawings for weld symbols, weld length and location, and members to be joined, was the root cause for the deviating welded joints.
The inadequate information was primarily due to the use of notes instead of detailed weld symbols (AWS A2.4) to provide the necessary welding information to the installer and/or fabricator.
These deficiencies have been confined to the cable tray connections associated with the subject vendor drawings manufactured by the specific supplier.
In order to evaluate the deficiencies and eliminate the possible adverse effects of these conditions on the seismic qualification of the tray system, a corrective action program was initiated.
Using " Tees" with minimum weld (worst case) configurations, weld requirements have been established which are applied to installed components through an engineering field verification program.
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SAFETY IMPLICATIONS This deficiency, had it remained uncorrected, may have prevented the cable
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tray system from performing intended design safety functions'and resulted.in an inability of associated safety-related systems to perform as required for safe operation and shutdown.
CORRECTIVE ACTION
, To establish and demonstrate minimum weld requirements and to determine that the installed components are acceptable, we have initiated the following:-
a) The minimum weld that.is acceptable, based on calculations, for each
" Tee" fitting configuration (size) has been identified.
b) A field survey-conducted per TE-FVM-CS-050, "T. J. Cope Flat Ladder Tee Fitting-Selected Attributes Data Collection," to determine weld conditions to " Minimum Weld Requirements" has been completed for both units.
A design change (DCA-41204) was issued for generic modification of installed fittings by adding bottom welds at " channel to stringer" joints.
c) Representative " Tee" fittings, with existing minimum weld conditions and modified per the. OCA, were subjected to static tests to confirm acceptability. Corporate Consulting & Development Co. (CCL) performed the
. required test with results documented per CCL Test Report No. CCL-A-742-87, dated May 1, 1987.
d) " Tee" fittings installed in the field, which are found to have deficiencies with respect to to tested " Tees", are being repaired as i
dispositioned by NCRs on a case by case basis.
" Tee" fittings that are stored in lay-down areas will be verified for acceptance prior to installation.
The results of our actions to date indicate that there are a total of two hundred fourteen (214) " Tee" fittings in Unit 1 and one hundred sixteen (116)
" Tee" fittings in Unit 2, which are affected by this issue.
A fraction of the fittings in Unit I were covered by thermolag which has been removed to permit access for inspection and repair of welds as necessary.
l Modification work of the installed trays has not been completed.
To date, approximately two hundred (200) have been modified in Unit 1.
In Unit 2, approximately ninety (90) have been modified.
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'TXX-6771 September 30, 1987 Page*3 Of 3 l
The modification work described above will be completed by March 1,1988.
Supporting documentation'will be available onsite for your Inspector's review after March 31, 1988.
Very truly yours, b
W. G.
nsi.
By: _
G. S. Keeley Manager Nuclear Li sing c-Mr. R. D. Martin, Re3.on IV Resident Inspectors (3) i k