Proposed TG Repair of Reinforced Concrete of Existing Nuclear Power Plants (RCTG) Chiara Ferraris, NIST Nate Sauer, Structural Technologies

Transcription

1 Proposed TG Repair of Reinforced Concrete of Existing Nuclear Power Plants (RCTG) Chiara Ferraris, NIST Nate Sauer, Structural Technologies

2 Status Over 100 NPP in service today and most of them have reached or are reaching the end of the licensing approval and in some cases service life. For continuing operation Application to NRC for an extension. Ideally for 80 yrs To obtain NRC approval, the owner needs to prove to NRC that all the passive structures are meeting the safety requirements and that they can continue to function as needed for the duration of the licensing process.

3 NRC/DOE Requirements The NRC/DOE states some of the development needed: Standardized degradation acceptance criteria Assessing long-term effects of exposure to radiation, heat, and the environment Developing environmental qualification standards and baseline degradation models of containment structures Development and testing of improved NDE techniques and targets for thick, heavily reinforced concrete

4 Challenges in NPP General Concrete Repair Cracking Spalling Strengthening Restoring Structural Capacity Seismic and Security Corrosion Aggressive Exposure Conditions Soil Conditions Below Grade Water Issues Infiltration Exfiltration Buried Pipe Initiative

5 Definition of Concrete Repair 1. Evaluation of the concrete structure 2. Development of the concrete repair strategy 3. Design and implementation of the repair 4. Monitor and document the repair

6 NPP License Extension Technologies requiring further research or certification Inspection/NDT Concrete Repair Cathodic Protection/Prevention Prestressing FRP Strengthening Pipe Repair and Strengthening Service-Life Prediction Moisture Control Fireproofing Security blast protection

7 Repair Industry standards American Concrete Institute Committee on Repair New Repair Code Developing International Concrete Repair Institute Concrete Repair Manual NACE Maintenance and Rehabilitation Cathodic Protection ISO standards

8 Initiative in Non-Nuclear ACI-SDC Vision 2020 Regular workshops Roadmap Goals: Statistical confidence of repair materials / technologies. Corrosion mitigation systems

9 Scope Establish coordination and consistency for safety and non-safety concrete repairs in existing nuclear power plants Identify repair requirements for safety related concrete components, and develop a plan to incorporate these new requirements into codes and standards. Collaboration with standard development organizations (SDO) will be required. Identify (NRC) Regulatory documents related to concrete repair for existing nuclear power plants and identify any needs.

10 Objectives Categorize codes and standards related to concrete repair in NRC documents Identify relevant repair concrete codes and standards missing from the NRC documents Identify technologies and new research that could translated in to new standards and codes to be adopted by an SDO Identify new technology and research needs to fill knowledge gaps in existing concrete repair codes and standards

11 Expected Results Inventory of relevant NRC standards with gaps and overlaps analysis. Recommendations for revision or new development of concrete repair standards Review of current citation of concrete codes and standards in NRC regulatory documents.

12 Task Group Membership Include representation from: relevant SDOs: e.g. ACI, ASME and AISC nuclear power plant industry (NSSS vendors, Engineering Design & Construction (EDC) firms, utilities) NRC staff (licensing and inspection) accredited/certifying concrete inspectors Other experts in specific fields as needed

13 Interested Members (35 so far) ACI, AMEC, Bechtel Power, Dominion Virginia Power, EPRI, Exelon, FMC Lithium Div., ICA Fluor, Southern Company, Univ. of Kansas, US-NRC, Advitam, Freyssinet, Wiss Janney Elstner Assoc Inc, ICRI, CVM Facilities Renewal, CTL group, Levelton Consultants Ltd, Electro Tech CP, STARS Group, Tourney Consulting, Palo Verde Nuclear Generating Station, U.S. DOE, Burns & McDonnell, Western Michigan University, Shaw Group, Walker Restoration Consultants, Sika Corporation, Moffat & Nichol, Constellation Energy Source, Ceratechnic, Concrete Reinforcing Steel Institute (CRSI), Water Reclamation Facility Technical Support, NFPA, Tec services, S&ME, NIST, Structural group

14 Proposed Schedule 4July 2011: Form a task group 4July 2012(?): 4Draft report on findings with recommendations 4Submit recommendation to NESCC

15 Questions? Comments?