Aging Management of Buried and Underground Piping and Tanks for Nuclear Power Plants in Canada

Transcription

1 Aging Management of Buried and Underground Piping and Tanks for Nuclear Power Plants in Canada IAEA/EPRI International Technical Meeting on Aging Management of Buried and Underground Piping and Tanks for Nuclear Power Plants Seyun Eom and Blair Carroll Technical Specialist John Jin Director Canadian Nuclear Safety Commission The views expressed herein are those of the authors and do not represent official positions of the Canadian Nuclear Safety Commission e-doc (PPT)

2 Presentation Outline Introduction Canadian Nuclear Safety Commission (CNSC) Status of Buried Pipe and Tanks in Canadian Nuclear Plants Regulatory Framework Overview of CNSC Core Processes CNSC Safety Control Areas (SCAs) Aging Management Overview of CNSC Regulatory Document, REGDOG Integrated Approach 9 Key Attributes in CNSC REGDOC Canadian Standards Association (CSA) N285.4 Overview CSA N285.7 Overview Risk Informed In-Service Inspection (RI-ISI) Risk Evaluation Concluding Remarks 2

3 Canadian Nuclear Safety Commission (CNSC) - Overview Canada s nuclear watchdog Quasi-judicial body Independent of, but not isolated from, government Our Mission Is Clear Regulate the use of nuclear energy and materials to protect the health, safety and security of persons and the environment Respect Canada s international commitments on the peaceful use of nuclear energy Disseminate objective scientific, technical and regulatory information to the public.

4 Status of Buried Pipe and Tanks in Canadian Nuclear Plants Power Reactor Operating License (PROL) requires that licensees have programs to ensure Fitness for Service of Structures, Systems and Components (SSCs) in accordance with referenced CNSC regulatory documents and Canadian Standards Association (CSA) standards REGDOG-2.6.3* on aging management is currently available. *supersedes RD-334 (2011) CSA Standard N285.4, periodic inspection of nuclear power plant components, referenced in operating licences Draft of CSA Standard N285.7 periodic inspection of CANDU nuclear power plant balance of plant pressure boundary systems and components currently issued for public review and comment No buried or underground piping transporting radioactive substances in Canadian nuclear plants under normal operating conditions Possible impact on nuclear safety due to degradation of buried pipe and tanks (i.e., some sections of Emergency Core Cooling (ECC) piping, main service water, fire protection piping, etc.)

5 Overview of Regulatory Framework Regulatory Framework Safety & Control Areas (SCAs), Licence Conditions Regulatory Requirements & Guidance CNSC Regulatory Documents (REGDOCs) & Canadian Standards Association (CSA) Standards 5

6 CNSC Safety and Control Areas (SCAs) 14 SCAs used by CNSC staff across all regulated facilities and activities in a comprehensive framework to assess, evaluate, review, verify and report on performance of regulatory requirements Functional Area Management Facility and Equipment Core Control Processes Safety and Control Area 1. Management Systems 2. Human Performance Management 3. Operating Performance 4. Safety Analysis 5. Physical Design 6. Fitness for Service SCAs particularly relevant to Aging Management 7. Radiation Protection 8. Conventional Health and Safety 9. Environmental Protection 10. Emergency Management and Fire Protection 11. Waste Management 12. Security 13. Safeguards and Non-Proliferation 14. Packaging and Transport 6

7 Aging Management Overview of REGDOC (2014*) CNSC s adoption and adaptation of IAEA NS-G-2.12 Aging Management of Nuclear Power Plants (2009) Covers all stages of NPP lifetime, including design, construction, operation, Long Term Operation (LTO), safe storage and decommissioning Requirements for: Integrated Aging Management Program (Plant Level framework / governance) Aging / Life Cycle Management Plans for specific SSCs or specific aging degradation mechanisms Safety Analysis and Risk Assessments to account for cumulative effects of aging Data and information collection for aging management and to confirm safety analysis assumptions and acceptance criteria continue to be met *supersedes RD-334 (2011) 7

8 Aging Management Integrated Approach Improve effectiveness of aging management programs Plan 2. Development and optimization of activities for aging management of a structure/component Preparing, coordinating, maintaining and improving activities for aging management Document regulatory requirements and safety criteria Document relevant activities Describe coordination mechanisms Improve effectiveness of aging management based on current understanding, self-assessment and peer reviews Minimize expected degradation Act 5. Maintenance of a structure/component Managing Aging Effects Preventive maintenance Corrective maintenance Spare parts management Replacement Maintenance history Mitigate degradation ` 1. Understanding aging of a structure/ component Key to effective aging management based on the following information: Materials and material properties, fabrication methods Stressors and operating conditions Aging mechanisms Sites of degradation Consequence of aging degradation and failures R&D results Operational experience Inspection/monitoring/maintenance history Mitigation methods Current status Reliability Check 4. Inspection, monitoring and assessments of a structure/component Detecting and assessing aging effects Testing and calibration Pre-service and In-Service Inspection Leak detection, vibration monitoring, etc. Assessment of functional capability/fitness for service Record keeping Do 3. Operation/use of a Structure/Component Managing Aging Mechanisms Operation according to procedures and technical specifications Chemistry Control Environmental Control Operating History, including transient records Check for degradation 8

9 Aging Management 9 Key Attributes in REGDOG Aging Management Plans (AMPs) and Life Cycle Management Plans (LCMPs) must comply with the requirements of CNSC REGDOC must be implemented in accordance with the overall Integrated Aging Management Program framework, and Must address the 9 attributes of an effective aging management program (same attributes as in IAEA NS-G-2.12 and International Generic Ageing Lessons Learned (IGALL)). 9 Attributes of an Effective Aging Management Program (e.g., monitoring/detection/acceptance criteria, etc.) Provide Sample Methodology* for Aging Evaluation in REGDOG (Sample Methodology*: Adapted from the IAEA NS-G 2.12 on Ageing Management of Nuclear Power Plants) 9

10 CSA N285.4: Periodic Inspection of CANDU nuclear power plant components - Overview CSA Standard N285.4 addresses periodic inspection requirements for pressure boundary systems - systems containing fluid that directly transports heat from nuclear fuel; - systems essential for the safe shutdown of the reactor of the safe cooling of the fuel, or both, in the event of a process system failure; and - other systems or components whose failure could jeopardize the integrity of the systems described in Item (a) or (b) or both. Clause establishes requirements for the inspection of systems potentially susceptible to corrosion and erosion - covers any buried piping 10

11 CSA N285.7: Periodic Inspection of CANDU nuclear power plant balance of plant pressure boundary systems and components - Overview Draft of CSA N285.7 currently issued for public review and comment CSA N285.7 will provide the minimum inspection requirements for periodic inspection program for balance of plant pressure boundary systems Buried piping in the scope of this standard Selection of the systems and components in the scope of the program based upon Risk-Informed In-Service Inspection (RI-ISI) methodology Expect to incorporate standard into operating licences when it is published 11

12 CSA N285.7: Periodic Inspection of CANDU nuclear power plant balance of plant pressure boundary systems and components RI-ISI 12

13 DEGRADATION CATEGORY Pipe Rupture Potential CSA N285.7: Periodic Inspection of CANDU nuclear power plant balance of plant pressure boundary systems and components Risk Evaluation Consequence Evaluation Failure Potential Assessment (Degradation Mechanism) HIGH NONE LOW MEDIUM HIGH LOW (Cat. 7) CONSEQUENCE CATEGORY CCDP and CLERP Potential MEDIUM (Cat. 5) HIGH (Cat. 3) HIGH (Cat. 1) MEDIUM LOW (Cat. 7) LOW (Cat. 6) MEDIUM (Cat. 5) HIGH (Cat. 2) LOW LOW (Cat. 7) LOW (Cat. 7) LOW (Cat. 6) MEDIUM (Cat. 4) 13

14 Closing Remarks CNSC Requires that licensees have programs to ensure Fitness for Service of Structures, Systems and Components (SSCs) in accordance with Power Reactor Operating License (PROL) Aging Management Plan (AMP) must be implemented in accordance with the overall Integrated Aging Management Program framework addressed in CNSC regulatory document, REGDOC CSA N285.4 referenced in operating licences CSA N285.7 is under development incorporating Risk Informed In-Service Inspection (RI-ISI) concept 14

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