ML14099A291

Letter to NDE IC on Comments to Industry Guidance Documents

ML14099A291
Person / Time
Site:	North Anna
Issue date:	06/09/2014
From:	Timothy Lupold Piping and NDE Branch
To:	Hacker K Dominion Generation
SCumblidge, NRR/DE/EPNB, 415-2823
References
Download: ML14099A291 (5)

Text

June 9, 2014 Kevin Hacker, Chair NDE Integration Committee Dominion Generation Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060

Dear Mr. Hacker:

In response to the five large stress corrosion cracks discovered in the inlet hot leg steam generator nozzle dissimilar metal weld (DMW) at North Anna Power Station Unit 1, the industry formed the nondestructive examination (NDE) Improvement Focus Group (NIFG).

The NIFG efforts focused on DMWs where site-specific mockups have been used and non-encoded examinations conducted. NIFG tasks not yet completed have been transferred to the NDE Integration Committee, of which you are the chair.

In 2013, the Electric Power Research Institute published the following reports to provide guidance for nuclear power plant owners with respect to improving the reliability of NDE:

1) Report 300200091, Nondestructive Evaluation: Guideline for Conducting Ultrasonic Examinations of Dissimilar Metal Welds, Revision 1

2) Report 3002000204, Nondestructive Evaluation: Performance Demonstration Initiative (PDI) Guidance for Improved Reliability in Ultrasonic Examinations These reports include:

1) Performance Demonstration Initiative (PDI), Site Specific Configuration Mockup Requirements for Dissimilar Metal Welds, Revision C

2) Guidelines For The Application Of Team Scanning For Ultrasonic Examination of Dissimilar Metal Welds (DMW)

NIFG requested Staff review of these guidance documents. The Staff provided comments to NIFG on these guidance documents, and these comments were discussed with NIFG at public meetings held on February 28, 2012 and June 4, 2013. These comments provided to NIFG and NIFGs decision to not address the comments by revising the guidance documents were discussed during a public meeting held on January 7-9, 2014. As an action item from the January 2014 meeting, NIFG requested the Staff to formally transmit their comments by letter to NIFG. This letter, including Enclosures 1 and 2 NRC Staff Concerns with: Performance Demonstration Initiative (PDI), Site Specific Configuration Mockup Requirements for Dissimilar Metal Welds, Revision C and NRC Staff Concerns with Guidelines For The Application Of Team Scanning For Ultrasonic Examination of Dissimilar Metal Welds, is provided to NIFG to complete this action item.

The Staff believes that these comments to be substantive and necessary to improve the performance of NDE when using either site specific mockups or team scanning. The NRC staff also requests that the NDE Integration Committee provide a response to these comments.

K. Hacker Should you have any questions regarding this letter, please contact Stephen Cumblidge at (301) 415-2823 Sincerely,

/RA/

Timothy Lupold, Chief Component Performance NDE and Testing Branch Division of Engineering Office of Nuclear Reactor Regulation

Enclosures:

1 and 2 as stated

K. Hacker Should you have any questions regarding this letter, please contact Stephen Cumblidge at (301) 415-2823 Sincerely,

/RA/

Timothy Lupold, Chief Component Performance NDE and Testing Branch Division of Engineering Office of Nuclear Reactor Regulation

Enclosures:

1 and 2 as stated cc: SCumblidge CNove WNorris DISTRIBUTION:

SCumblidge CNove WNorris ADAMS Accession Number: ML14099A291 OFFICE NRR/DE/EPNB NRR/DE/EPNB RES/DE/CIB NAME TLupold SCumblidge CNove DATE 06/09/2014 5/22/2014 05/22/2014 OFFICIAL RECORD COPY

U.S. Nuclear Regulatory Commission (NRC) Staff Concerns with Performance Demonstration Initiative, Site Specific Configuration Mockup Requirements for Dissimilar Metal Welds, Revision C These comments were given at the Public Meeting on February 28, 2013 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML13071A165) and have not yet been addressed:

Requirements with respect to quantity, size, type, and locations of implanted flaws in the mockups need to be well-defined. One flaw in each orientation is insufficient as one flaw cannot cover a range of sizes, angles, or locations. Using only small flaws or one flaw location does not cover the range of possibilities in the field.

Designing robust acceptance criteria for open testing is challenging, it is possible that blind testing is simpler than open testing. Predetermined and quantitative acceptance criteria need to be developed prior to testing.

Modelling of the ultrasonic search unit should be mandatory.

Paragraph 10.2 should be struck from the document as it is unnecessary and the language is open to abuse.

In addition to the Authorized Nuclear Inservice Inspector (ANII), the staff would like the performance demonstration administrator (PDA) to review and approve the procedure and technical basis document as the new procedure would be considered qualified.

The staff believes that the Technical Basis Document should be sent to the PDA and that it becomes part of the record for equipment, procedure and personnel.

ENCLOSURE 1

U.S. Nuclear Regulatory Commission Staff Concerns with the Concept of Team Scanning These comments were given at the public meeting held on June 4, 2013 (ADAMS Accession No. ML13159A012) and have not yet been addressed. The comments were given in the context of the proposed testing of team scanning that was conducted in July of 2013, after these comments were provided. The testing described in the presentation has been completed and represented a proof of concept of team scanning under ideal conditions. The comments are as follows:

The implementation of team scanning in the field is performed under a wide range of conditions.

For example, inspectors may or may not be able to see each other, inspectors may or may not have worked together before, and the training levels of inspectors can vary greatly. There has been no work done to date to determine the important variables in team scanning or the effects of these variables on the effectiveness of the scanning. How can the NRC staff be assured that team scanning is effective in the field if the effects of these variables are not known?

American Society of Mechanical Engineers Boiler and Pressure Vessel Code,Section XI, Appendix VIII, describes a minimum list of essential variables, but does not take team scanning variables in to account. Which variables in team scanning should be considered essential?

Should procedures have to list the team design as an essential variable?

Many variables in team scanning can be eliminated by limiting the implementation of team scanning. Requiring line of sight, direct communication, and requiring both parties to have a view of the instrumentation would significantly reduce the uncertainties caused by team scanning. Other variables can be eliminated by establishing formal requirements such as minimum team-scanning training requirements and minimum team scanning experience requirements.

ENCLOSURE 2