A830023, Summarizes Completed Corrective Action on Mark I Mod Welds Installed by Unqualified Welders.Welds Examined & Modified If Needed

Summarizes Completed Corrective Action on Mark I Mod Welds Installed by Unqualified Welders.Welds Examined & Modified If Needed

ML20085N595
Person / Time
Site:	Cooper
Issue date:	10/07/1983
From:	Pilant J NEBRASKA PUBLIC POWER DISTRICT
To:	Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
LQA8300231, TAC-07934, TAC-7934, NUDOCS 8311110126
Download: ML20085N595 (3)

Text

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LQA8300231 October 7, 1983 TE4@{ MOM E

• s Mr. John T. Collins OCT 131983 Regional Administrator U.S. Nuclear Regulatory Commission , , _

d Region IV h 611 Ryan Plaza Drive Suite 1000 Arlington, TX 76011 Subj ec t : Mark I Modification; Welds Performed by Unqualified Welders

Reference:

1) Nebraska Public Power District letter, J. M. Pilant to J. T. Collins dated April 13, 1983; Mark I Modification -

Welds Performed by Unqualified Welders

Dear Mr. Collins:

In reference 1 you were informed that the District discovered that some penetration welds performed by Dravo Utility Constructors Inc. (DUCI) during our Mark I Modification Program work were accomplished by un-qualified welders. We described our intended course of corrective action and advised that you would receive a summary report after the work had been completed.

Using procedures recognized by ASME, the District performed a detailed evaluation of all flare bevel, full and partial penetration groove welds installed by DUCI during and af ter the Spring 1982 outage. Ultrasonic examination of welds was done by 02neral Electric and engineering analysis assistance was conducted by the Impell Corporation (formerly EDS Nuclear). Each weld was eithar found to be adequate to carry the design loading or a modification was designed and installed to encure adequacy as summarized below:

1. All flare bevel welds installed by unqualified welders were evaluated and found to be acceptable. The evaluation assessed the load-carrying capacity of welds made by fillet welders in all the weld locations where flare bevel welds were installed.

2. All flare bevel welds installed by qualified welders are acceptable for the following reasons:

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8311110126 831007 ~

I fDRADOCK 05000298 PDR t _._ _ _ . _ _ _ _

Mr. John T. Collins October 7, 1983 Page 2

- The qualified welders demonstrated the ability to perform welding more complex than that of a fillet welder.

- Welds made by the qualified welders were in the same or similar connections as those evaluated and found acceptable for the unqualified welders.

3. All full and partial penetration groove welds installed by unqualified welders were evaluated with the following results:

- 41 welds acceptable by UT

- 20 welds acceptable by analysis:

- stress levels in welds with reportable indications were less than allowable limits

- where testing was not possible, existing fillet welds were sufficient to carry load

- 29 welds unacceptable:

- stress levels in welds with reportable indications were-above allowable limits

- when testing was not possible, additional fillet welding was added to carry load

- modifications were designed and installed to qualify con-nections.

4. All full and partial penetration groove welds installed by qualified welders, including welds without consumable inserts made by welders qualified to DUCI procedure 1101.CI, were evaluated with the following results:

- 161 welds acceptable by UT

- 38 welds acceptable by analysis:

- stress levels in welds with reportable indications were less than allowable limits

- where testing was not possible, existing fillet welds were sufficient to carry load

- 17 welds unacceptable:

- stress levels in welds with reportable . indications were above allowable limits

- when testing was not possible, additional fillet welding was added to carry load QL

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Mr. John T. Collins October 7, 1983 Page 3

- modifications were designed and installed to qualify con-nections.

Specific details of the wock accomplished are available for your review.

Please contact my office if you have any questions concerning this matter.

Sincerely,

, . Pilant Technical Staff Manager Nuclear Power Group CAT:cmk

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