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NRC Section XI Report - February 2006

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Presented By:  Mr. Wally Norris, United States Nuclear Regulatory Commission

NRC Report
February 2006

1.    Amendments to 10 CFR 50.55a


A final amendment to 10 CFR 50.55a incorporating by reference the 2001 Edition up to and including the 2003 Addenda of the ASME Boiler and Pressure Vessel Code, was published on October 1, 2004 (69 FR 58804).  The rule became effective on November 1, 2004.


The staff has completed the technical bases for the amendment to 10 CFR 50.55a to endorse the 2004 Edition.  Development of the proposed rule is proceeding.  A public meeting has tentatively been scheduled on Monday, May 15, 2006, from 5:30 - 7:30 pm during the ASME meetings in Phoenix, AZ, to discuss the proposed changes to 10 CFR 50.55a to incorporate by reference the 2004 Edition.  The meeting will be formally noticed through the NRC public meeting web site.  The purpose is to present the NRC's basis for any new limitations and modifications that are being considered for 10 CFR 50.55a and solicit comments from stakeholders and other interested parties.  It is the staff’s intent to publish the proposed rule for public comment in summer 2006.


2.    ASME Code Cases - Rulemaking/Regulatory Guides


Three final regulatory guides addressing ASME Code Cases were noticed in the Federal Register on September 29, 2005, (70 FR 56938-56939) - Revision 33 to Regulatory Guide 1.84, “Design, Fabrication, and Materials Code Case Acceptability, ASME Section III; Revision 14 to Regulatory Guide 1.147, “Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1; and Revision 1 to Regulatory Guide 1.193, “ASME Code Cases Not Approved for Use.”  The guides address the Code Cases in Supplement 12 to the 1998 Edition through Supplement 6 to the 2001 Edition.  The guides are available electronically in the Regulatory Guides Document Collection of the NRC's public Web site at

http://www.nrc.gov/reading-rm/doc-collections/reg-guides/power-reactors/active/index.html .


Draft Revision 34 to RG 1.84, Draft Revision 15 to RG 1.147, and Draft Revision 2 to RG 1.193 have been reviewed and approved for publication (public comment).  Approval has also been received from the Committee to Review Generic Requirements and the Advisory Committee on Reactor Safeguards to publish the draft guides for public comment.  The guides address the Code Cases in Supplement 7 to the 2001 Edition through Supplement 1 to the 2004 Edition.  The proposed rule endorsing the draft regulatory guides is in concurrence.  It is the staff’s intent to publish these guides for public comment in the first quarter of 2006.


The staff is currently reviewing Supplements 2, 3, 4, 5, and 6 to the 2004 Edition.


3.    Risk-Informed Activities


10 CFR 50.69 ‑ Risk Informed Special Treatment Requirements


The final version of Regulatory Guide (RG) 1.201 is being prepared for publication for trial use.  The trial use period is expected to be completed by the end of 2006.


Request to Extend Reactor Vessel Weld Inspection Interval by One Operating Cycle


Three Licensees have submitted requests to extend the inspection interval for the reactor vessel welds by one operating cycle.  The requests referred to NRC guidance provided in a letter from the Nuclear Regulatory Commission to Westinghouse Electric Company, "Summary of Teleconference with the Westinghouse Owners Group Regarding Potential One Cycle Relief of Reactor Pressure Vessel Shell Weld Inspections at Pressurized Water Reactors Related to WCAP-16168-NP, "Risk Informed Extension of Reactor Vessel In-Service Inspection Intervals," dated January 27, 2005.  Palisades’ request has been approved and issued.


4.    Generic Activities on Material Degradation/PWR Alloy 600/182/82 PWSCC


By letter dated July 27, 2005, the Nuclear Energy Institute (NEI) transmitted to the NRC for information EPRI Materials Reliability Program Report MRP-139, Rev. 0, “Materials Reliability Program: Primary System Piping Butt Weld Inspection and Evaluation Guideline.”  It was indicated that NEI was not requesting approval of MRP-139 but would appreciate NRC staff comments on the document.  On August 4, 2005, a public meeting was held between NRC and representatives from NEI and MRP during which an overview of the report was given and general staff observations were provided.  In a letter to Alexander Marion, Senior Director Engineering/Nuclear Generation Division, Nuclear Energy Institute, from Michael Mayfield, Director, Division of Engineering, Office of Nuclear Reactor Regulation, dated October 12, 2005, the NRC staff identified portions of the document it believed should be clarified and enhanced.


By letter dated December 14, 2005, NEI submitted MRP-169, Technical Basis for Preemptive Weld Overlays for Alloy 82/182 Butt Welds in PWRs, for NRC review and approval (sections 4.0, Design Requirements, and 7.1, Requirements for Types of Examination for Weld Overlays; the remainder of MRP-169 was submitted for information only.)  The letter indicated that approximately six utilities are prepared to implement this methodology in 2006.


The staff met with representatives of NEI, MRP, and EPRI on January 17, 2006 to discuss areas for future cooperation in the area of material degradation research.


A meeting was held on February 6, 2006, to update the Commission on the subject of materials degradation and fuel performance.


5.    New Reactor Licensing Activities


The final safety evaluation report (FSER) and Final Design Approval (FDA) for the AP1000 design certification were issued on September 13, 2004.  Notice has been sent to interested parties to announce the issuance of the design certification final rule (DCR), dated January 27, 2006, for the Westinghouse AP1000 design.  This final rule amends 10 CFR Part 52 to certify the AP1000 standard plant design.


The staff is reviewing early site permit (ESP) applications for three sites: North Anna, Clinton, and Grand Gulf.  All three applications were accepted for docketing in late 2003.  The staff completed the safety evaluation reports for North Anna and Grand Gulf in June and October of 2005.  The staff expects to complete the Clinton FSER in February of 2006.  The environmental reviews are in progress and the staff expects to complete those reviews over the next few months.  The completion of the FSERs and EIS will then be followed by a mandatory hearing on all three proposed ESPs.


The staff is currently engaged in certification review of General Electric's ESBWR design.  The design certification application was submitted to the NRC in August 2005, and once accepted for docketing, the certification review is expected to take 48 months.  In addition, the staff is currently engaged with vendors in pre-application review of several other new and innovative reactor designs, including the EPR design (Framatome ANP), the Pebble-Bed Modular Reactor (PBMR) design (PBMR Pty Ltd.), the Advanced Candu Reactor (ACR)-700 design (Atomic Energy of Canada, Ltd.), and the International Reactor Innovative and Secure (IRIS) design (Westinghouse Electric Company).


6.    Examination of Cast Austenitic Stainless Steel


A draft NUREG/CR report  was completed in December 2005 on the application of an inside diameter surface eddy current (ET) method to detect surface-breaking cracks in centrifugally and statically cast piping and is in the NRC review process.  The ET technique was successful at detecting all open cracks in the Westinghouse Owners Group (WOG) specimens, and provided insights on discrimination of cracks in the presence of geometrical and metallurgical features.


NRC-funded research using low-frequency (500 kHz) phased array ultrasonic testing, as applied from the outside surface, is continuing at PNNL as a potential method to detect cracks in cast piping components.  Early tests with a prototype 500 kHz array showed good results for flaws that are 25-30% through-wall in depth, using simple line scans and steering the ultrasonic beam for inspection angles from 30 to 60 degrees.  A newly designed 500 kHz array with a smaller footprint and enhanced ultrasonic properties is currently being evaluated in the laboratory.  This array uses state-of-the-art piezo-composite elements and allows both beam steering in the active aperture and beam skewing in the passive aperture.  This means that cracks in the WOG specimens having major cross-sections, or branches, that are oriented off-axis to the primary ultrasonic beam may now be better detected and imaged.  Preliminary results show an improved signal-to-noise response with less input gain using the new array.  The smaller footprint of the new array also allows access to more of the WOG specimens with challenging outside surface geometries.


Data acquisition on the WOG specimens is on-going, to be followed by measurements of coherent ultrasonic noise from the microstructure of vintage centrifugally cast piping segments on loan from Westinghouse, IHI Southwest, Inc. and EPRI.  These measurements will help to understand the nominal background noise one might expect from piping in the field, evaluating how to determine these noise properties on field piping, and how this noise may impact detection capability of the technique.


The cast work is scheduled to be completed, and documented in a draft NUREG/CR to be submitted to the NRC by end of April 2006.  The results from this work will be presented to ASME Code committees in future ASME Code meetings during May and August 2006.

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