NG-08-0093, Response to Request for Additional Information Related to the Relief Request for Seal Weld Procedure Qualification
| ML080590357 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 02/19/2008 |
| From: | Richard Anderson Duane Arnold |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NG-08-0093 | |
| Download: ML080590357 (6) | |
Text
aFPL Energy.
Duane Arnold Energy Center FPL Energy Duane Arnold, LLC 3277 DAEC Road Palo, Iowa 52324 February 19, 2008 NG-08-0093 10 CFR 50.55a U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555-0001 Duane Arnold Energy Center Docket 50-331 License No. DPR-49 Response to Request for Additional Information Related to the Relief Request for Seal Weld Procedure Qualification References
- 1. Letter, Gary Van Middlesworth (FPL Energy Duane Arnold) to Document Control Desk (USNRC), Relief Request for Seal Weld Procedure Qualification, dated July 31, 2007, NG-07-0588 (ML072220137)
- 2. Letter, Karl D. Feintuch (USNRC) to Richard L. Anderson (FPL Energy Duane Arnold), Request for Additional Information Re:
Relief Request for Seal Weld Procedure Qualification (TAC NO.
MD6293), dated February 15, 2008 (ML080390553)
Reference 1 provided a request for relief to allow weld procedure specifications for seal welding of the installed and spare Main Steam Relief Valves (MSRVs) to be post-qualified in accordance with ASME Section IX requirements. That relief is requested for the Fourth Ten-Year Interval of the Inservice Inspection Program for the Duane Arnold Energy Center (DAEC), which began on November 1, 2006.
By letter dated February 15, 2008 (Reference 2), the Staff issued a request for additional information regarding Reference 1. The response to the request of Reference 2 is provided in the enclosure to this letter.
FPL Energy Duane Arnold requests approval of the request of Reference 1 by the end of May 2008.
This letter contains no new commitments nor revises any previous commitments.
A04-7
NG-08-0093 February 19, 2008 Page 2 of 2 If you have any questions, please contact Steve Catron at (319) 851-7234.
Richard L. Anderson Vice President, Duane Arnold Energy Center FPL Energy Duane Arnold, LLC Enclosure cc:
Administrator, Region III, USNRC Project Manager, DAEC, USNRC Senior Resident Inspector, DAEC, USNRC
Enclosure to NG-08-0093 Page 1 of 3 Enclosure Response to Request for Additional Information Related to the Relief Request for Seal Weld Procedure Qualification
Enclosure to NG-08-0093 Page 2 of 3 Response to Request for Additional Information Related to the Relief Request for Seal Weld Procedure Qualification NRC Question #1:
On page 2 of the relief request under "Reason for Request," the second sentence states "The Manufacturer's standard included multiple surface Non-Destructive Examinations (NDE) and macro examinations of sectioned specimens." What were the specific NDE and macro examination methods used and what were the acceptance criteria for these examinations?
FPL Energy Duane Arnold Response:
The original welding procedure specifications were qualified in accordance with Target Rock's procedure, TRP-1 139. This procedure classified both the seat-to-body and the bellows-to-spacer plate seal welds as "Special Welds."
Surface Examinations:
TRP-1 139 required "Special Welds" to receive a liquid penetrant (LP) examination as part of acceptance. The procedure qualification records (Target Rock referred to these as "Metallurgical Test Reports") show an LP examination of the root and final passes for the bellows-to-spacer plate seal weld and an LP examination of each pass for the seat-to-body seal weld were performed. The acceptance criteria listed in TRP-1 139 for the LP examinations states, "Liquid penetrant inspection shall not disclose any linear indications or cracks, and no rounded indications exceeding 1/32 inch diameter. A maximum of five indications (1/32 inch diameter) shall be permitted per linear inch of weld."
Macro Examination of Sectional Specimens:
TRP-1 139 states Special Welds, "shall be metallographically examined with sufficient microspecimens (four maximum) to fully evaluate fusion to base metal, penetration, weld bead contour, soundness, grain size, heat affected zone in base metal, etc." TRP-1 139 acceptance criteria for macro examination states, "Metallographic examination shall show sufficient (but not excessive) penetration, a good sound fusion zone, a weld bead contour which follows the joint geometry, freedom from porosity exceeding.010 inch diameter and no cracks." The workmanship samples used for procedure qualification listed on the Metallurgical Test Reports were polished, etched, and examined under magnification.
Enclosure to NG-08-0093 Page 3 of 3 NRC Question #2:
What NDE was performed on the affected components after the current repair/replacement activities and how do those methods and the acceptance criteria used for those methods compare with the requirements of the current applicable edition and addenda of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code,Section XI?
FPL Energy Duane Arnold Response:
The Target Rock documentation package for Purchase Order (PO) P101779 was reviewed (PO P101779 is the off-site repair/replacement activity in 2004 that initially raised this issue). Both the seat-to-body and bellows-to-spacer plate seal welds were subject to an LP examination of their root and final passes. The acceptance criteria are provided in NWS Technologies LP procedure, NWS-NDE-P-01, Rev. 2, which meets ASME Section III, Subsection NB (Class 1) requirements. NWS-NDE-P-01 is written to comply with ASME Section III, Subsection NB, 1992 Edition, 1993 addenda. The ASME Section III, Subsection NB, LP acceptance criteria is unchanged up to the current 2007 Edition.
The current code of record for the DAEC is the 2001 Edition, 2003 Addenda of the ASME Code,Section XI, for repair/replacement activities.Section XI allows the Owner to follow the original construction code requirements, or the requirements of a newer edition/addenda of the construction code. Therefore, the use of NWS-NDE-P-01, Rev. 2, meets the requirements of ASME Section XI, 2001 Edition, 2003 Addenda.
The method and number of tests (LP examination of root and final passes) exceed ASME Section III, Subsection NB requirements. ASME Section III, Subsection NB, requires either an LP or a magnetic particle examination to be performed on the final weld surface.