ML19270H012

Interim Deficiency Rept on 790529:five Loose Wire Terminations Found on Status Display Panel Modules of Main Control Panel.Caused by Insufficient Mfg & Insp Procedures.Insp Procedures Being Upgraded

ML19270H012
Person / Time
Site:	Midland
Issue date:	06/07/1979
From:	James Anderson BECHTEL GROUP, INC., BECHTEL POWER CORP.
To:
Shared Package
ML19270H007	List: ML19270H006 ML19270H012
References
HOWE-173-79, NUDOCS 7906220363
Download: ML19270H012 (3)

Text

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a t Attachment 2 Howe-173-79

' Bechtel Associates ProfessionalCorp_ ation

Subject:

MCAR #28 Interin Report 1 Date: June 7, 1979 Project: Consu=crs Power Company ltidland Plant Units 1 & 2 Bechtel Job 7220 Introduction This report is submitted to advise regarding the interim status and course of action required pursuant to MCAR #28 and Bechtel NCR #2176.

Description of Discrepancy Eechtel field inspection of the installed ESFAS status display light nodules on panel 1C14 revealed discrepancies regarding the soldered wire connections as follows:

Svitch Terminal Problem Description ISV-0127 G Not soldered ISV-0127A G Loose solder joint ISV-0127A C Cold solder joint dig-1257 C Not soldered IMO-5336A A Not soldered 1110-0912 G Wire touching movable member The vire connections on the status display panel modules for panels 1C14 and 2C14 were inspected by the QA manager of tie vendor (Magnetics, a division of Spang Industries) and Bechtel engireering on May 22,.1979.

This inspection has revealed the need for more thorough inspection for all status display modules on panels IC14, 2C14 and OC10. Following is the preliminary response to the reco= mended actions:

1. Determine what effect the discrepant material could have on plant safety if uncorrected.

From the electrical schemes and wiring diagrams we have determined that if these problems are uncorrected they could cause:

a) loss of safety display indication 2348 047 b) false indication c) overheating and possible burn out.of the voltage dropping resistor d) prelhtinary findings show there is no likelihood of blowing a fuse in the control circuit because the dropping resistors are connected in such a way that any grounding or touching of the stoveable parts vill cause the voltage dropping resistors to overload and overheat and possibly burn out. g

- l' age 2 of 3 June 7, 1979 MCAR 28 I!;TERIM REPORT 1 None of the above conditions is likely to disabic the control circuit.

2. Examine other soldered components by Magnetics. Other components by Magnetics include the following:

a) light display units for panels 1C14, 2C14 and OC10.

b) amphenol connectors for 1C14 and 2C14 light display units.

There are no amphenol connectors for panel 0C10.

c) Resistor banks for OC10, IC14 and 2C14 light display units.

d) Nonsafety reltted digital indicators.

Light display units for panel IC14 and 2C14 are detachabic and have been snipped back to Magnetics, the panel vendor, for necessary inspection and corrections.

The other components listed above will be checked in the field per the schedule which is presently being established between Bechtel at.d Magnetics.

3. Determine why Magnetics Quality Assurance Program and Bechtel Procurement Supplier Quality Program did not detect this discrepant material.

a) Magnetics Quality Assurance Program: A specific, detailed inspection plan for soldered connections was not a part of QA program, which resulted in an inadequate inspection of sol-dered connections.

b) Ecchtel Pror.urement Supplier Quality Program: Bechtel Procure-ment Supplier Quality Program calls for random surveillance inspection only. Further, supplier quality representative inspection might not have been adequate because of lack of detailed inspection criteria. .

4. Determine if a functional check would have revealed the above discrepant conditions. -

A functional test of the status display lamp assemblics was per-formed and was co-witnessed by Bechtel SQR and Eechtel engineering.

This tcst indicated that all functions were performed satisf a.--

torily. It is, therefore, concluded that a functional test of these assemblies or other componcats woulo not necessarily detect soldering deficiencies.

5. Based on the above 4 items determine reportability under 10 CFR 50.55e by May 25, 1979.

Because of the indeterminate nature of the possibic failure modes and therefore the possibility that safety related circuits may have been rendered inoperable, it is suggested that this problem should be considered reportable under 10 CFR 50.55c.

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Page 3 of 3 ,

1 CAR 28 1!

TEMIM pep 0RT 1 l

6. Probable Cause(s)

Present investigation indicates that lack of specific detailed manufacturing and inspection procedures for soldering operations was the probable cause of the discrepant material. The supplier used general type procedures which lacked the required amount of detail to assure the level of quality required.

Although a functional test of the status display light assemblies was performed and indicated satisfactory results, the nature of the problem appears to be undetected by functional test.

7. Corrective Actions

'Ihc following corrective actions will be taken to prevent recur-rence of the discrepant material.

a) Require Magnetics to submit a comprehensive, detailed manu-facturing and inspection program for soldering practices.

b) Magnetics to perform 100% reinspection of all soldered wire terminations and connections for the status display light assemblics and associated cociponents and devices.

c) Bechtel field quality control (QC) to perform inspection at completion of Item 2. Bechtel supplier quality representative (SQR) to perforn 100% inspection of modules at the supplicr's plant prior to shipment to jobsite.

d) Ecchtel procurement supplier quality department (San Francisco) h.is issued a st pplier quality action request to all offices and supplier quality representatives requesting investigation of their suppliers for similar problens. Upon receipt and review of the responses, procedures will be developed to provide a comprehensive supplier surveillance program.

Forecast Date on Corrective Actiom A schedule for the corrective actions will be provided in interitr report no. 2. .

Submitte M R f= .

' Approved by: _,_./ Mr Concurrence by: ,C%9 BECHTEL ASSOCIATES PROFESSIONAL CORP 0pATION 2348 049

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