ML20214U860
| ML20214U860 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 11/20/1986 |
| From: | Russell J, Stewart D TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML20214G966 | List:
|
| References | |
| WP-13, WP-13-R, WP-13-R00, NUDOCS 8612090425 | |
| Download: ML20214U860 (7) | |
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I TVA EMPLOYEE CONCERNS REPORT NUMBER: WP-13 SPECIAL PROGRAM REPORT TYPE: Welding Project REVISION NUMBER: 0 TITLE: Suitability of Welding Equipment for Construction and Modifications Welding Activities REASON FOR REVISIOE: N/A SWEC
SUMMARY
STATEMENT: N/A PREPA** TION PREPARED BY:
Original Signed By J. E. Rose 04-03-86 SIGNATURE DATE REVIRWS PEER:
Original Signed By R. M. Bateman 04-03-86 SIGNATURE DATE TAS: TECHNICAL VIEW ONLY ll f W$
SIGNATURE DATE CONCURRENCES Original Signed By CEG-H:
L. E. Martin 09-03-86 f
O'20 h SRP*
-a SIGNATURE DATE SIGNATURE
- DATE APPROVED BY:
'k N/A ECSP MANAGER DATE MANAGER OF NUCLEAR POWER DATE CONCURRENCE (FINAL REPORT ONLY)
- SRP Secretary's signature denotes SRP concurrences are in files.
8612090425 861124 2242T PDR ADOCK 05000327 P
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WELDING PROJECT GENERIC EMPLOYEE CONCERN 7
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EVALUATION REPORT REPORT NUMBER:
WP-13-SON. R0 DATE 04-08-86
SUBJECT:
SUITABILITY OF WELDING EQUIPMENT FOR CONSTRUCTION AND MODIFICATIONS WELDING ACTIVITIES CONCERNS CONSIDERED: IN-85-247-002 IN-85-303-001 PREPARED BY Original Signed By J. E. Rose 4/3/86 OC, WP r
REVIEWED BY Original Signed by R. Bateman 4/3/86 OC, WP 0
REVIEWED BY - Original Signed by R. P. Lynskey 4/3/86 QA, WP
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d CEG-H, WELDING REVIEWED B
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) 1h PROGRAM MANAGER APPROVED BY m.
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00320-
3 GENERIC EMPLOYEE CONCERN S_UMMARY SHEET
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Report Number:
WP-13-SON. R0 h'
Report
Title:
SUITABILITY OF WELDING EQUIPMENT FOR CONSTRUCTION AND MODIFICATIONS WELDING ACTIVITIES I
I.
CONCERNS CONSIDERED:
IN-85-247-002 IN-85-303-001
[
II.
ISSUES INVOLVED y
i 1.
Welding machines (grid packs) do not have suitable control settings for welding with 3/32-E7018 electrodes.
I 2.
This unsuitability leads to porosity and pinholes in completed welds.
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3.
All GTAW equipment should have remoto (high frequency are starting) switches so that tungsten inclusions can be avoided.
III. STATEMENT OF CONCERN / ISSUE VALIDITY Validity: Y
,N I
, Substantiated: Y
,N I
j IV.
EFFECT ON NARDWARE AND/OR PROGRAM None s
V.
JUSTIFICATION The equipment described in the concerns does have sufficient features j
to make acceptable quality welds. All safety-related systems receive inspections in accordance with the QA program.
VI.
RECOMMENDATION AND/OR CORRECTIVE ACTION NEEDED None f-VII. REINSPECTION NEEDED: Y
,N X
VIII.
ISSUE CLOSURE By this report.
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IX.
ATTACHMENT ii 1.
Text of Employee Concerns i
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Page 1 of 1 2
00320
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GENERIC EMPLOYEE CONCERN Report Number:
WP-13-SON, R0 Report
Title:
SUITABILITY OF WELDING EQUIPMENT FOR CONSTRUCTION AND MODIFICATIONS WELDING ACTIVITIES 4
I.
SCOPE OF EVALUATION This engineering analysis covers the following WBN concerns determined to have possible generic implications at SQN:
IN-85-247-002 IN-85-303-001 II.
ISSUES ADDRESSED BY CONCERNS Each concern was analyzed'to determine the issues voiced by the concerned individuals. These issues are as follows:
1.
Welding machines (grid packs) do not have suitable control settings for welding with 3/32-E7018 electrodes.
I
- 2. 'This unsuitability leads to porosity and pinholes in completed
- welds, d
3.
All GTAW equipment should have remoto (high frequency are starting) switches so that tungsten inclusions can be avoided, i
III. CONCERN VALIDITY OR SUBSTANTIATION The construction and modifications standards (AWS, ASNE ANSI B31.1) for welding provide general statements concerning suitability of welding equipment for particular operations. The standards simply i
state that welding equipment is to be suitable for performing the f
particular welding operations for which they are used. This general j
guidance provides the only code and standard reference to suitability i
of welding equipment'for particular operations.
i The choice of and assignment of particular types of welding equipment I
is made based on overall management and engineering judgements relative to the type activity to be accomplished, working conditions, space limitations, equipment availability, and suitability.
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Page 1 of 3 00320
m WP-13-SQN, R0 When large sophisticated welding equipment such as full sized GTAW 3
equipment is removed from a particular work area and is replaced with a
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more compact and simple type egulpment (grid packs or multiple operator systems) which will satisfactorily perform the same welding operations, some unnecessary convenience features such as extremely fine current control and high frequency arc starting are not available. The lack of these features, which are not necessary for the production of satisfactory welds, does not affect the overall quality of the welds which they produce.
Welders are accustomed to the convenience and ease of operation of the more sophisticated equipment. They may not be fully aware that factors such as space limitations may dictate the use of smaller less i
sophisticated equipment which will still perform acceptably but may-require more individual skill and attention by the welder to perform operations such as GTAW with multiple operator welding equipment.
Further, the welders may simply not personally agree with such decisions and will complain about alleged inadequacies and unsuitability of particular equipment when such equipment will perform satisfactorily.
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Multiple operator welding systems have been used in the nuclear construction industry for both GTAW and SMAW welding operations and have a history of satisfactory service. They are not, however, as convenient to use as GTAW equipment which has additional features such as high frequency are starting and remote roostat current control; and, as such, they do not have the welder appeal that large GIAW equipment does which can be used for either GTAW or SNAW welding.
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Nultiple operator units have a minimum five ampere welding current adjustment feature. Many units have a two and a half ampere minimum current adjustment. This current adjustment is not as sophisticated as the vernier current adjustments on GTAW equipment but is suitable for optimum current settings for both SMAW and GTAW welding operations.
I A review of commonly used Detail Welding Procedure specifications used for Construction and Nodification Work lists a current range of 75 to l
115 amps for 3/32-E7018, 100-145 amps for 1/8 E7018, and 130-205 amps for 5/32-E7018 for SMAW welding. The current range for GTAW procedures is35-130 amps. The current settings on multiple operator units are l
well within the acceptable range for both GTAW and SMAW welding.
Nost of the welder performance qualification testing at Sequoyah, during both the construction and operations phases, have been conducted using inultiple operator-type welding equipment systems without high frequency starting. This same type of equipment is utilized at the Browns Ferry Test Shop and in TVA's Nobile Test Shop. The satisfactory use'of this equipment for welder testing demonstrates its ability to produce acceptable welds.
Further, its use demonstrates the ability of TVA's welders to perform acceptable welds using multiple operator j
welding machines without high frequency starting. Test welds made using this equipment do not demonstrate an extraordinary high amount of tungsten inclusions as would be evidenced if the premise of the concern
'I held true.
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WP-13-SQN. R0 The issue of pinholes and porosity is a symptom of p,or welding-technique. Correct are starting techniques for low hydrogen electrodes will eliminate starting porosity. Correct welding technique (holding a short are length) and weld prep cleanliness, will eliminate pinholes in the deposited weld bead if correct welding current settings are used.
The issues of remote current and high frequency are starting controls are basically convenience features which welders prefer to have on their equipment.
These features are not necessary for the production of acceptable quality GTAW welds. Strike plates can be utilized for GTAW are initiation and will effectively eliminate tungsten inclusions from GTAW welds.
An independent verification of welding equipment suitability can be made through inspections of completed welds. The WP reinspection at SQN did not reveal a large amount of problems mentioned in the concerns.
Based on the foregoing analysis, the issues considered in the subject concerns are to be closed based on the following factors:
1.
There is no industry standard which mandates the use of specific welding equipment for specific jobs.
2.
Equipment in use has sufficient control features to produce welds within the required criteria.
3.
Alternate techniques can be used to compensate for the lack of sophisticated features on multiple operator-type equipment and still produce acceptable quality welds.
4.
The WP reinspection did not discover any indications of a generic problem with welding equipment.
5.
There is no effect on hardware due to these issues.
These issues are closed based on this report.
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,e, 04/23708 (EMPLOYEE COllCERNS) '
PAGE 1 of 1
'11:25:C8 LOC STAfUS REST
-CTC-PPP CFR
'IflSP TC ------COrlCER!1-------
PROBLEt1 ID
- )
EGEG fl0 SR IN-85-ES7-OO2 WCMWE.
.WORDS:
EQUIPt1ENT WELD T1ACHIllE t1CKAY & HOBART X: W Y: C 2: N WELDING MACHINES (MCKAY & HOEART) USED IN FIELD SY STEAM FITTERS HAVE 2 SETTIkOS 50 8 100 AMPS BOTH OF WHICH ARE UNSUITABLE FOR WELDING WITH 3/32" ROD. THIS CutlTRIBUTES TO POROSITY AND PINHOLES TECHNICAL COMMENTARY:
ISSUES CONSIDERED:1.WELDIt;G f1ACHINES (GRID PACKS)DO NOT HAVE SUITABLE C0!iTROL SETTINGS FOR WELOING WITH 3/32 E7018 ELECTRODES. 2.THIS UNSUITASILITY LEADS TO PORO"ITY AND PINHOLES IN COMPLETED WELDS.
LOC STATUS RESP
-CTC-PPP CFR INSP TC ------CONCERN-------
PROBLEM ID EGEG NO SR IN-85-303-001 WCMWE XEYWORDS:
EQUIPMENT WELD MACHINE REMOTE SWITCH X: W Y
C 2: N ALL THE WC'. DING MACHINES SHOULD HAVE REMOTE SWITCHES 50 THAT THE TUNGSTEN TIP DOESN'T HAVE TO TOUCH THE BASE T1ETAL TO START THE WELD. PRESENTLY THE NOff-HOBART WELDERS, WHEN USED, t1AY CAUSE' TUNGSTEN TO BE LEFT IN THE WELD TECHNICAL COf1f1ENTARY:
'JES CONSIDERED:
. hLL GTAW EQUIPt1ENT SHOULD HAVE REMOTECHIGH FREQUENCY ARC STARTING) SWITCHES IHAT TUNGSTEN INCLUSIONS CAN BE AUDIDED.
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