ML070610457
| ML070610457 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold, PROJ0704  |
| Issue date: | 02/28/2007 |
| From: | Eaton W Electric Power Research Institute |
| To: | Matthew Mitchell Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 2007-061 | |
| Download: ML070610457 (6) | |
Text
ELECTRIC POWER RESEARCH INSTITUTE 2007-061 BVVR Vessel & Internals Project (BWRVIP)
February 28, 2007 6 0J -'704 Document Control Desk 5 -31 U. S. Nuclear Regulatory Commission 11555 Rockville Pike Rockville, MD 20852 Attention:
Matt Mitchell
Subject:
BWRVIP Actions in Response to Flaw Indications in Recirculation Inlet Piping Nozzle to Safe End Welds at Duane Arnold The purpose of this letter is to inform the NRC staff of the actions that the BWR Vessel and Internals Project (BWRVIP) is taking in response to recent flaws being identified in the recirculation inlet piping nozzle to safe end welds at the Duane Arnold Energy Center (DAEC) plant.
The BWRVIP and DAEC continue to share information regarding the developments at DAEC.
In response to the indications of cracking, the BWRVIP has transmitted the enclosed letter to the BWRVIP Executive Committee advising them of the situation, recommending several actions and requesting that specific information be promptly provided to the BWRVIP. The BWRVIP will compile this information, evaluate the fleet responses and determine what, if any, actions should be taken by the BWRVIP or its members based on the information received. The BWRVIP will also work with DAEC to share lessons learned with the industry. The BWRVIP will continue to communicate with the NRC regarding the information received and any planned actions or recommendations.
If you have any questions on this subject please contact Robin Dyle at Southern Nuclear by telephone at 205.992.5885 or Randy Stark at EPRI by telephone at 650.855.2122 or by e-mail at rstark@epri.com.
Sincerely, Entergy Operations, Inc.
Chairman, BWR Vessel and Internals Project Together Shaping the Future oF Electricity ep,.
Ila-H lji.*l811 PALO ALTO OFFICE 3420 Hillview Avenue, Polo Alto, CA 94304-1395 USA e 650.855.2000 9 Customer Service 800.313.3774
- www.epri.com
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BWRVIP Executive Committee NEI Materials Executive Oversight Group NEI Materials Technical Advisory Group Alex Marion, NEI Rick Jacobs, INPO
- tmI, l
ELECTRIC POWER RESEARCH INSTITUTE 2007-051 BWR Vessel & Internals Project (BWRVIP)
URGENT - IMMEDIATE ACTION REQUIRED February 23, 2007 TO:
BWRVIP Executive Committee FROM:
William A. Eaton Entergy Operations, Inc.
Chairman, BWR Vessel and Internals Project
SUBJECT:
Request for Information on Dissimilar Metal Weld Examinations Inspections performed during the current outage at Duane Arnold have revealed indications in recirculation inlet piping nozzle to safe end welds. Additional information regarding these inspections is attached. Updates will be provided as additional details regarding the size and nature of the indications is made available by Duane Arnold.
Due to the significance and potential generic implications of these indications and the fact that the NRC has requested additional information and evaluations from the BWRVIP, the BWRVIP is gathering pertinent information to assist in responding to these NRC requests.
Therefore, please complete the attached BWRVIP Response Form, and return the form by email to Amardeep Puaar at apuaarwiiepri.com no later than the close of business on Friday March 2, 2007.
The information gathered will also be utilized to determine future BWRVIP actions and to continue to respond to NRC and other industry requests for information, as appropriate.
Until such time as the BWRVIP completes the reviews and evaluations of the requested information, the BWRVIP has the following interim recommendations for immediate implementation:
- 1. All plants should review all previous inspection data and experience since 1998 for each dissimilar metal weld including potential impacts of the following: weld configuration, effect of weld crowns on previous inspections, inspection methods utilized (e.g., manual, automated UT, type of transducers, PDI qualified, etc.), variations in UT methods/techniques or inspection vendors during different outages, the potential for transducer lift-off during previous inspections, etc.
- 2. Plants with Spring 2007 outages with no plans to inspect dissimilar metal welds should reevaluate those plans in light of the Duane Arnold experience, including consideration of Together... Shaping the Future of Electricity PALO ALTO OFFICE 3420 Hillview Avenue, Palo Alto, CA 94304-1395 USA
- 650.855.2000
- Customer Service 800.313.3774
- www.epri.com
your plant-specific weld inspection histories. Plants may receive questions from NRC regarding outage plans and the rationale used if no examinations are planned in the current outage.
The BWRVIP will continue to keep you informed as additional information becomes available and as additional recommendations are developed.
If you have any questions on this subject please contact Robin Dyle at Southern Nuclear by telephone at 205.992.5885 or Randy Stark at EPRI by telephone at 650.855.2122 or by e-mail at rstark@epri.com.
c:
BWRVIP Integration Committee BWRVIP Assessment Committee BWRVIP Inspection Focus Group BWRVIP Technical Chairmen BWRVIP EPRI Task Managers Alex Marion - NEI Rick Jacobs - INPO
Duane Arnold Plant Recirculation Piping Nozzle to Safe End Weld Inspection Information February 2007
- 1. Inspection Scope The DAEC inspection schedule for recirculation piping nozzle to safe end welds is in conformance with both ASME Section XI and BWRVIP-75-A for both frequency and extent.
- 2. Nozzle Configuration The approximately 13.12 inch outside diameter (OD) by 11.00 inch inside diameter (ID) safe-end to nozzle weld is Alloy 82 and connects the Alloy 600 (SB-166) safe-end to the SA-508 Class 2 low alloy steel nozzle, buttered with Alloy 182. A portion of the original Alloy 82/182 safe-end to nozzle weld remains on the nozzle side as a result of installing a modified safe-end with an integrally attached thermal sleeve prior to going into service. There are 8 recirculation nozzles with this configuration, two of which were overlaid during prior outages. Additionally, there are 2 approximately 8 inch core spray nozzles that have thermal sleeves.
- 3. Inspection Method Manually-driven, encoded phased array. Equipment, personnel, and procedure have been qualified in accordance with ASME Section XI, Appendix VIII. Note that weld crowns on all DM welds were machined flush in 2005 per PDI requirements.
- 4. Results of Inspections Recirculation riser nozzle-to-safe-end weld RRF-F002 (N2F).
Planar flaw was reported, wholly contained in weld and butter Circumferential Located at the weld to butter interface Reported length is -61 degrees Reported depth 0.59" of 1.1" thickness (55.6%)
Remaining ligament to the outside surface 0.47" Data evaluation is continuing -- the reported size might be adjusted Data being independently reviewed by EPRI Recirculation riser nozzle-to-safe-end weld RRC-F002 (N2C)
Examined as part of the 1st expansion sample Planar flaw was reported, wholly contained in weld and butter Circumferential
I Reported length - to be determined Reported depth - to be determined Data being independently reviewed by EPRI
- 5. Previous Inspection results RRF-F002 (N2F).
2005 Data No flaw indications reported in 2005, but recent EPRI review concluded that evidence of the indication is present. The data quality in the area of the indication appeared to have been compromised by mechanical factors related to the scanner.
1999 Data Data was compromised due to weld crown, however there is some evidence present in data that the indication was present in 1999
- No sizing possible due to data quality 0
1996 Data Data compromised due to weld crown cannot pick out evidence of flaw
- Data worse than 1999
- Indication could have been present, but undetectable due to crown condition RRC-F002 (N2C)
- Previously examined in 1999 Data currently in review