ML11356A287
| ML11356A287 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 11/11/2011 |
| From: | Carpenter C, Appajosula Rao Office of Nuclear Regulatory Research |
| To: | Atomic Safety and Licensing Board Panel |
| SECY RAS | |
| Shared Package | |
| ML11356A279 | List: |
| References | |
| RAS 21617, 50-247-LR, 50-286-LR, ASLBP 07-858-03-LR-BD01 | |
| Download: ML11356A287 (26) | |
Text
NYS000305 Submitted: December 22, 2011 ML111801154 NRC Aging Management Program Including Long Term Operation (LTO)
Dr. Appajosula S. Rao Group Leader IASCC Program and C. E. (Gene) Carpenter, Jr.
Group Lead for Aging Management Issues U.S. Nuclear Regulatory Commission Office of Nuclear Regulatory Research For presentation at the Workshop on Challenges on the Long Term Operation, 21st SMIRT Meeting, New Delhi, India, Nov. 8-11th 2011 OAGI0001407_00001
U.S.NRC Global Age of NPPs United States Nuclear Regulatory Commission Protecting People and the Environment Number of Operating Reactors by Age 35 . -----------------------------------------------------------------------------------.
33 32 30 ---------------------------------------------------------------------------- -
25 ------------------------------------------------------------------------ .24. - -
22 22 21 21 20 ---------------------------------------------------------------------- - -t9----------------
18 16 15 ------------------------------------------------------------------ 4.- ------ - ~ 4- - - - - - - - - - - - - - - - - - -
13 12 11 11 10 10 10 --------------------------------------------------- - - - - - - -
7 7 6 6 6 6 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 Note: Age of a reactor is determined by its first grid connection. [year]
Source: International Atomic Energy Agency; http://www.iaea.or.at/programmes/a2/
vg 2 OAGI0001407_00002
Integration of Domestic Nuclear Research Programs INDUSTRY NRC DOE
- Profit motive /
- Public health and
- Long term shareholder safety protection national interest perspective perspective perspectives
- Short term research
- Confirmatory
- Long term addressing known research research problems and addressing known addressing managing costs / safety issues predictive and d
downtime ti i improvement t opportunities
- Ex: Better testing and repair
- Ex: Crack precursors and
- Ex: IASCC - Better, faster weld repairs needed for reliability and integrity assurance methods irradiation damage need to be reduce field repair times needed understood for better Life Beyond 60 Program predictions and future material selection Long Term Operability Program LWR Sustainability Program Individually, each program addresses a specific perspective; collectively, they address the majority of issues that need to be answered for safe extended operations.
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NRC Aging Management Research Approach h Identify Degradation Scenarios Not Addressed in NUREG-1801, Generic Aging Lessons Learned (GALL) Report
- Identify Inspection and Monitoring Programs and Associated Requirements for Highly Likely Degradation Scenarios h Assess Results from Implementation of License Renewal Aging Management Programs and Recommend Improvements for Subsequent License Renewal Periods h Develop Domestic and International Partnerships to Share Expertise, Capabilities and Resources Related To Aging Management Research vg 4 OAGI0001407_00004
Materials Degradation Issues Key h Extending safe operating life of NPPs will require comparing known modes of materials degradation, and identifying emerging degradation mechanisms, with expected service life to identify potential issues
- Materials degradation can lead to increased maintenance, increased downtime, and increased risk h Materials issues must be resolved for:
- Reactor Pressure Vessels and Primary Piping
- Core Internals
- Secondary Systems
- Weldments
- Concrete
- Cable insulation
- Buried Piping vg 5 OAGI0001407_00005
Aging R&D Areas U.S.NRC United States Nuclear Regulatory Commission Protecting People and the Environment Primary System Secondary System Turbine Rotor: low alloy steel Condenser structural: Blades: 17-4PH, 403 SS Vessel : Alloy steel SG vessel wall : Blade attach: low alloy steel Low alloy steel Water side: carbon steel Clad: 308, 309 SS RPV RPV: Alloy steel RPV cladding:
308, 309 ss Control rod: Power SS clad B4 C + SS poison transformer Core structurals: 304 SS High strength: A 286, X 750f(~llii'F!F(Fjili\"\l Fuel cladding :
Zy-4 , advanced Zr alloys Fuel: U0 2 Cooling water:
River or sea water, cooling tower L....-- Core Internals Ex-vessel Systems and Balance of Plant vg 6 OAGI0001407_00006
Aging Effects for Existing NPPs "Bathtub" Curve 100 New Discoveries Aging Effects 80 Failurre Rate 60 40 20 Unknown T 0
-5 15 35 Time55 75 95 vg 7 OAGI0001407_00007
Materials Degradation History y = 7.1429x + 1951.3
- 1958 - Vibration Fatigue 2010
- 1970 - Corrosion Fatigue 1990
- 1984 - Erosion Corrosion 1980 D ate (yy ear)
- 1987 - Microbial-Induced C
Corrosion i 1970
- 1993 - IGSCC in TP347 1960 Stainless Steel
- 2001 - PWSCC 1950
- ????? 1940 1930 Vibration TP304 Corr.- Erosion- MIC TP347 PWSCC fatigue IGSCC fatigue corr. IGSCC vg 8 OAGI0001407_00008
Proactive Management of Materials Degradation
- Develop information
- Materials behavior
- Mitigation or repair
- Inspection or monitoring
- Proactively address Avoid Surprises e.g. V.C.
potential future degradation Summer And Davis Besse
- Avoid failures
- Maintain integrity g y and safety
- Increase cooperation
- Prioritize PMMD research with industry
- Pursue additional international collaborations
- Evaluate existing requirements
- Integrity of susceptible components
- Inspection and monitoring regulations vg 9 OAGI0001407_00009
Proactive Management of Materials Degradation 3/4 Extension of service life may cause new challenges for materials service
- Increased lifetime leads to increased exposures
- Time at temperature
- Stress
- Coolant
- Neutrons
- Extending reactor life to 40, 60 years or beyond will likely increase susceptibility and severity of known forms of degradation
- New mechanisms of materials degradation are possible The motivation of several Department of Energy, Nuclear Regulatory Commission and Electric Power Research Institute projects is to provide improved understanding of degradation under extended service and provide alternative mitigation strategies.
OAGI0001407_00010
Organized PMDA Approach h Research must also identify other or new topics before they become life-limiting Knowing the unknowns is a difficult problem that must be addressed.
Difficult issue for such a complex and varied material/environment system.
h Together with the DOE - LWRS program, USNRC is working to expand the initial PMDA activity (NUREG 6923) to encompass broader systems and longer lifetimes.
Core internals and primary piping Pressure Vessel Concrete Cabling h NRC updating and expanding PMDA to capture operating period beyond 60 years and to expand scope OAGI0001407_00011
Expanded PMDA h NRC Developed NUREG/CR-6923, Expert Panel Report on Proactive Materials Degradation Assessment
- Published February 2007
- Scope encompassed passive components in primary, secondary and some tertiary systems of BWRs and PWRs, the failure of which could lead to a release of radioactivity or affect functionality of safety systems h NRC updating p g and expanding p g PMDA scope p to capture p
operating period beyond 60 years
- EMDA will ascertain gaps in present level of understanding of materials degradation during subsequent license renewal periods EMDA will look at materials in passive, long-lived systems, structures and components (e.g., RPV steels, concrete, cables, underground piping, etc.)
- NRC and DOE LWRSP collaborating on developing EMDA vg 12 OAGI0001407_00012
Metal Fatigue h Analysis methodology could yield non-conservative results h Potential delay in implementation of planned corrective actions to address aging h Requiring license renewal applicants to demonstrate that their analysis results are conservative vg 13 OAGI0001407_00013
Submerged Electrical Cables h Cables not designed for continuous submerged service in electrical manholes h Cable failure can disable safety systems h Revised inspection procedures and program guidance to increase and expand inspection and test frequencies vg 14 OAGI0001407_00014
Electric Cable Insulation h Cable failures worldwide increasing with plant age h Cables provide power needed to operate equipment and transmit signals to and from the various controllers h Research to confirm whether requirements for electrical equipment are being met through an extended period vg 15 OAGI0001407_00015
Steel Containment and Liner Plate Degradation h Corrosion due to water leakage or contact with wood or foreign objects h Potential impacts on structural integrity and leak tightness h Obtained applicant commitments for additional inspections and increased maintenance; issuing advisory to other licensees vg 16 OAGI0001407_00016
Neutron Absorber Degradation h Long-term use of neutron absorbers in spent fuel pools leads to deformation and degradation of the materials h Potentially reduce safety margins and may violate sub-criticality b iti lit requirement i t h Developed new aging management program for neutron absorbing materials degradation vg 17 OAGI0001407_00017
Refueling Cavity/Spent Fuel Pool Leakage h Concerns regarding the impacts of historical water leakage from concrete walls and floors h Potential effect on structural integrity and leak tightness h Obtained commitments from license renewal applicants vg 18 OAGI0001407_00018
Buried Piping h Corrosion on soil side of piping h Potential effects on system safety and release of hazardous material h Enhanced agency guidance to increase inspections and focus on key preventive measures vg 19 OAGI0001407_00019
Prolonged Concrete Exposure to High Temperature and Radiation h Prolonged exposure to elevated temperatures and radiation facilitates chemical interactions and induces strains h Compromise concrete performance h Research on sufficiency of current methods to evaluate effects and the effects themselves vg 20 OAGI0001407_00020
Reactor Vessel and Internals h Irradiation embrittlement is the life-limiting factor for the reactor vessel and core internal components 3/4 NRC RES is actively pursuing to compile and prepare a comprehensive database of all the information on irradiation embrittlement of reactor vessel and core internal components to conduct confirmatory research on IASCC, neutron embrittlement and void swelling in LWR reactor core internals vg 21 OAGI0001407_00021
AMP Assessments h Staff is preparing to assess the ability of Licensees Aging Management Programs to successfully detect and manage aging degradation of safety-related safety related systems systems, structures and components vg 22 OAGI0001407_00022
International Forum for Reactor Aging Management h IFRAM promotes worldwide cooperation to address NPP aging management issues
- Cooperation includes sharing of data and specimens as well as facilitating joint research agendas and promoting work that addresses high priority issues and concerns.
h Participation in IFRAM provides an extended pool of resources and expertise to work on common problems
- Promote global cooperation on management of reactor aging
- IFRAM d does not replace l any existing i i cooperative i efforts ff h IFRAMs rationale is that:
- Organizations worldwide share common challenges
- Magnitude and scope of these challenges is beyond what any one organization can accomplish with their limited time and resources
- Cooperation is a powerful tool to economize resources, save time, and minimize needless duplication of efforts in addressing these challenges vg 23 OAGI0001407_00023
Concept Behind IFRAM h IFRAM will consolidate available information, coordinate cooperation on activities, facilitate information exchange and provide opportunities to bring together different national and regional views on topics and, where appropriate, harmonize agreed-upon best practices h IFRAM will cooperate with many parties and cut across numerous boundaries but it will not replace any cooperation efforts ff t that th t currently tl exist i t
- Its basic role is to facilitate research and information sharing h IFRAM is not intended to be an NRC-led (or regulatory-led, utility-led, university-led, or research organization-led) entity
- Since membership in IFRAM is open to all organizations, leadership roles will be given those members willing to support IFRAMs goals.
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Third International Conference on NPP Life Management for Long Term Operation 14-18 May 2012 Salt Lake City, Utah OAGI0001407_00025
Conclusion h Research is necessary to establish basis for long-term operation of existing nuclear plants beyond 60 years, and this research will:
- Answer safety questions on aging, reliability, and long-term operability of systems, structures and components h Industry has lead role to drive the process and identify issue resolutions
- Ultimately, Ultimately life extension is utility business decision h NRC ensures that safety-significant issues are identified and resolved in a timely manner
- It is not NRCs responsibility to resolve any potential aging issues that may impact continued safe operation of existing fleet
- NRC seeking to cooperate/collaborate with DOE, domestic industry and international partners in an integrated, holistic program to ensure long-term safety vg 26 OAGI0001407_00026