SBK-L-10148, Response to Draft Request for Additional Information Re Request for Alternate Depth Sizing Qualification

Response to Draft Request for Additional Information Re Request for Alternate Depth Sizing Qualification

ML102500268
Person / Time
Site:	Seabrook
Issue date:	08/31/2010
From:	Freeman P NextEra Energy Seabrook
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
SBK-L-10148
Download: ML102500268 (5)

Text

NExTera August 31, 2010 SBK-L-10148 Docket No. 50-443 U. S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852 Seabrook Station Response to Draft Request for Additional Information Regarding a Request for Alternate Depth Sizing Qualification

Reference:

NextEra Energy Seabrook letter SBK-L-10056, 10 CFR 50.55a Request for Alternate Depth Sizing Qualification, dated March 25, 2010.

In the referenced letter, NextEra Energy Seabrook, LLC (NextEra) submitted a request pursuant to 10CFR 50.55a(g)(5)(iii) for approval to use an alternate depth sizing qualification for volumetric examinations of the reactor pressure vessel (RPV) nozzle-to-safe end dissimilar metal (DM) welds from the inside surface.

The attachment to this letter provides NextEra's response to a draft request for additional information received from the NRC in an e-mail dated July 28, 2010 (TAC NO. ME3623)

(ML102090683).

If you have any questions regarding this response, please contact Mr. Michael O'Keefe, Licensing Manager, at (603) 773-7745.

Sincerely, NextEra Energy Seabrook, LLC Paul 0. Freeman Site Vice President NextEra Energy Seabrook, LLC, P.O. Box 300, Lafayette Road, Seabrook, NH 03874

U. S. Nuclear Regulatory Commission SBK-L-10148 Page 2 cc: NRC Region I Administrator G.E. Miller, Project Manager, NRC Project Directorate 1-2 W. J. Raymond, NRC Resident Inspector

Attachment to SBK-L-10148 ATTACHMENT Response to Draft Request for Additional Information Regarding a Request for Alternate Depth Sizing Qualification By letter dated March 25, 2010, NextEra Energy Seabrook, LLC, (NextEra) submitted a request pursuant to 10CFR 50.55a(g)(5)(iii) for approval to use an alternate depth sizing qualification for volumetric examinations of the reactor pressure vessel (RPV) nozzle-to-safe end dissimilar metal (DM) welds from the inside surface.

NextEra's response to a draft request for additional information, received from the NRC in an e-mail dated July 28, 2010 (TAC NO. ME3623) (ML102090683), is provided below:

NRC RAI No. 1 The submittal states that "as an alternative to the required RMS error stated in paragraph 3.3(c) of Code Case N-695, NextEra will add the difference between the required RMS error of 0.125-inches and the actual RMS error achieved by the chosen inspection vendor, up to a maximum of 0.224-inches, to the flaw depth as determined during flaw sizing." Please discuss the acceptance criteria that will be applied in the event that an indication is detected that requires depth sizing, considering that the ASME 2007 Edition with 2009 Addenda no longer permits the use of IWB-3514 for PWRs with nickel alloy welds that are susceptible to PWSCC for planar, surface-connected flaws that are in contact with the reactor coolant environment during normal operation. Additionally, MRP-139, Section 7, Evaluation Methodologies, specifies that "any flaw attributed to PWSCC, regardless of depth, will be evaluated even if it meets the IWB-3500 requirements."

NextEra Response to NRC RAI No. 1 In the NextEra submittal dated March 2 5th, 2010, relief is being requested to use an alternative to the qualification requirements of ASME Code Case N-695. The NRC has requested that a discussion be provided regarding the acceptance criteria that will be applied in the event that a flaw is detected. The NRC has also asked that consideration be given to the fact that the ASME Section XI -2007, 2009 Addenda, doesn't allow for the use of IWB-3500 and that MRP-139, Section 7, Evaluation Methodologies, specify that "any flaw attributed to PWSCC, regardless of depth, will be evaluated even if it meets the IWB-3500 requirements." Based on the request and follow-up discussions with the NRC, NextEra provides the following response.

Applicability of the ASME 2007 Edition w/ 2009 Addenda Section XI IWB requirements The Code of Federal Regulations, 10 CFR 50.55a, Codes and Standards mandates and regulates the use of ASME Section XI. As such, restrictions in 10 CFR 50.55a can necessitate deviation from, or modifications to, the ASME Section XI requirements. The Edition and Addenda incorporated by reference in paragraph (b) of 10 CFR 50.55a is the 2004 Edition of

ASME Section XI with no Addenda. The 2007 Edition with Addenda is not approved for use by 10CFR50.55a, paragraph (b).

Additionally, 10 CFR 50.55a(g)(4)(ii) requires that all successive Inspection Intervals shall comply with the requirements of the latest edition and addenda of the ASME Code incorporated by reference in paragraph (b) of 10 CFR 50.55a in effect 12 months prior to the start of the 120-month inspection interval. The Seabrook 3 rd In Service Inspection (ISI)

Interval began August 19th, 2010. The latest Edition and Addenda incorporated by reference in paragraph (b) of 10 CFR 50.55a on August 19, 2009 (12 months prior to the start of the 3 rd Inspection Interval) is the 2004 Edition of ASME Section XI with no Addenda.

The 2007 Edition with Addenda is not approved for use by 10CFR50.55a, paragraph (b).

Therefore, the ASME B&P V code, 2007 Edition with the 2009 Addenda,Section XI, IWB requirements are not applicable to Seabrook and could not be used without relief.

Applicability of MRP-139 NextEra complies with the guidance of MRP-139 in accordance with the "NEI 03-08 Guideline for the Management of Materials Issues," which committed each U.S. nuclear utility to the processes and guidance contained in MRP-139.

Flaw acceptance at Seabrook For the 3 rd ISI Interval at Seabrook Station, NextEra will use the acceptance requirements of ASME Section XI, 2004 Edition with no addenda along with the guidance contained in MRP-139, implemented in accordance with the NEI 03-08 protocol until such time that 10 CFR 50.55a restricts or modifies their use.

NRC RAI No. 2 Please provide an item number for the welds included in this submittal.

NextEra Response to NRC RAI No. 2 The welds included in the March 25, 2010 submittal are item number "B15.10" in accordance with the 2004 Edition of ASME B&P Vessel Code,Section XI, Table IWB-2500-1, Category B-F, "PRESSURE RETAINING DISSIMILAR METAL WELDS IN VESSEL NOZZLES."