ML12335A483
| ML12335A483 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 06/01/2010 |
| From: | John Lubinski NRC/NRR/DCI |
| To: | Atomic Safety and Licensing Board Panel |
| SECY RAS | |
| References | |
| RAS 21619, 50-247-LR, 50-286-LR, ASLBP 07-858-03-LR-BD01 | |
| Download: ML12335A483 (15) | |
Text
United States Nuclear Regulatory Commission Official Hearing Exhibit NYS000328 Entergy Nuclear Operations, Inc. Submitted: December 22, 2011 In the Matter of:
(Indian Point Nuclear Generating Units 2 and 3)
ASLBP #: 07-858-03-LR-BD01 Docket #: 05000247 l 05000286 Exhibit #: NYS000328-00-BD01 Identified: 10/15/2012 Admitted: 10/15/2012 Withdrawn:
Rejected: Stricken:
Other:
UNITED STATES NUCLEAR REGULATORY COMMISSION Protecting People and the Environ1nent NRC Perspectives on PWR Materials Issues John W. Lubinski, Deputy Director Division of Component Integrity o
Office of Nuclear Reactor Regulation
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Introd uction
~ Retired St. Lucie Pressurizer Nozzle Flaws
- Highly complex technical issues
- Significant level of attention by all NRC stakeholders
- Level of dedication by staff on both sides to try to get things right o
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PWR RPV Internals Aging Management
~ Historical Background
- PWR internal components may be subject to a number of degradation mechanisms
- Degradation management an issue for license renewal and power uprates
- Materials Reliability Program project o
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PWR RPV Internals Aging Management
~ Topical Report MRP-227 submitted for NRC review in Spring 2009
- Evaluated components based on susceptibility to a variety of mechanisms and consequences of component failure
- Divided components into several "bins" for inspection
- Identified inspection technologies to be used for component inspection o
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PWR PWR Internals Aging Management
~ Next steps
- Review of MRP-227 is a high priority
- Review of plant-specific aging management programs
- Implementation of MRP-227 by other licensees o
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~7U.S.NRC Davis-Besse RPV Head L~ :::':;:';:=':'== era c ki n 9
~ Historical background
- Cracking and head corrosion in 2002
- Replacement head from Midland installed - also Alloy 82/182/600
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~ Current status
- Licensee performed RPV head inspection in Spring 2010 and found evidence of boric acid deposits and indications of primary water stress corrosion cracking in their nozzles and welds
- The inspections identified penetration nozzles and/or welds with indications of cracking o
- Timing and extent of cracking was unexpected G>
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~Next steps
- Licensee performing half-nozzle repairs on all nozzles with indications
- NRC staff reviewing licensee's engineering assessment of the as-found condition of the RPV head
- Potential generic implications o
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OOSCC of Stainless Steel Piping
~ Recent operating experience
- Fall 2008 - Leak in Callaway Pressurizer Auxiliary Spray Line
- Fall 2008 - Indications in Wolf Creek Pressurizer Auxiliary Spray Line
- Fall 2009 - Leaks found in multiple lines at San Onofre, Units 2 and 3 o
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OOSCC of Stainless Steel Piping
~ Current status
- Industry researching operating experience databases for additional instances of ODSCC
- Typical instances of ODSCC involved TGSCC due to chloride contamination of 304 stainless steel piping
- NRC preparing an Information Notice o
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OOSCC of Stainless Steel Piping
~Next steps
- Industry in the process of developing inspection and evaluation guidelines to be issued under NEI 03-08, "Guideline for the Management of Materials Issues"
- NRC staff will continue to monitor operating experience and review industry guidelines when issued o
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Repair and Mitigation Technology
~ Focus on repair or mitigation of PWSCC in Inconel piping butt welds
- Weld overlay/inlay/onlay repair and mitigation
- Mechanical stress improvement
~ Developments in welding-based repair and mitigation technology have lead to a variety of o
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Repair and Mitigation Technology
~ NRC staff focus areas
- Welding with Inconel Alloy 52
- Implementation of new or advanced welding techniques
- Implications of the application of weld overlays to Leak-Before-Break approvals o
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Repair and Mitigation Technology
~Next Steps
- NRC will continue to place significant resources on monitoring and reviewing the development of welding-based repair and mitigation technology
- Issuance of Regulatory Issue Summary (RIS) regarding weld overlays and Leak-Before-Break o
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Conclusions
~ Understand that the NRC staff looks at every materials degradation issue from both a plant-specific and generic perspective
~ Communication between the industry and NRC is a key issue
~ Proactive measures to deal with potential o
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