Post Fukushima Safety Margins

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2 Post Fukushima Safety Margins Nuclear Codes and Standards Workshop Prague, Czech Republic July 7, 2014 Bryan Erler P.E. Chair Task Group on Design Basis and Response to Severe Accident and Vice President, ASME Conformity Assessment

3 Outline Global Initiative Following the Accident ASME Leadership Thoughts on Safety Margins 3

4 Global Support International Atomic Energy Agency IAEA World Association of Nuclear Operators WANO 4

5 IAEA Initiatives International Seismic Safety Center Response & Assistance Network RANET Site and External Events Design Services -SEED Emergency Preparedness Review IPREV 5

6 IAEA Seismic and Tsunamis Report 6

7 WANO Programs Peer Reviews Operating Experience Sharing Technical Support and Exchange Professional and Technical Development 7

8 United States Regulator s Action Issue Three NRC Orders Station Blackout Mitigation Strategies Containment Venting Spent Fuel Pool Instrumentation Issued Four Request for Information Seismic Reevaluation Flooding Reevaluations Seismic and Flooding Walkdowns Emergency Preparedness 8

9 United States Regulator s Action Issued Three Rulemaking Initiatives Station Blackout Mitigation Strategies Emergency Response Capabilities Filtration and Confinement Strategies 9

10 ASME Leadership BNCS Design Basis and Response to Severe Accident Task Group ASME s Presidential Task Force 10

11 Task Group Organization and Process Standards &Certification Council Efforts 1. Task Group with Proposed Title Design Basis and Response to Severe Accidents Purpose is to coordinate with nuclear committees and other internal / external S&C stakeholders, as required, on potential standards impacts Should include NEI, NRC, and JSME Should monitor internal and external developments 2. Council on Standards and Certification to coordinate needs and activities across S&C sectors and ASME enterprise working with above Task Force Process Need process & template for gathering input & keeping it current Should address Short term and long term actions Current reactor and new reactor applications All Stakeholders needs- SDOs, Suppliers, Regulators 11

12 Containment Integrity Focus Areas Pressure Boundary Integrity Hydrogen Control Severe Accident Management Guidance for Response and Recovery 12

13 Goals Develop a data base on the damage resulting from the incident in each of the focus areas Form teams of experts to review the data and make recommendations on potential code and standards development initiatives Provide the recommendation to the responsible ASME standards committees for their consideration Provide input to JSME on their guidelines 13

14 Task Group Structure Task Group Design Basis and Severe Accident Response Safety System and Component Integrity Severe Accident Mitigation and Response Design basis accident Hydrogen Control Severe Accident Response and Recovery Pressure Boundary Containment Integrity 14

15 ASME Standards Possibly Effected Task Group Design Basis and Severe Accident Response Safety System and Component Integrity Severe Accident Mitigation and Response Section III Section XI RA-S O&M CONAGT RA-S 15

16 ASME Presidential Task Force on Response to Fukushima Events Review events that occurred at the nuclear power plants at the Fukushima Daiichi station and events and subsequent activities in the U.S., Japan and elsewhere Identify ASME s role in addressing issues and developing lessons learned Disseminate ASME s perspective on the impact of these events on the future direction of the world-wide nuclear power industry 16

17 Deliverables Deliverables are anticipated to include disseminating conclusions and guidance in a comprehensive spectrum of media that may include: Interactive public workshops Congressional briefings Technical report 17

18 Thoughts on Future Safety Margins Design Basis Loadings ASME Vessel Integrity Assurance Actions to Assure Containment Integrity Containment Design Detail Changes Containment Structural Design Basis Reactor Vessel Design Basis 18

19 Design Basis Loadings Review of all nuclear plants external events design basis to verify the last data and approach has been used Establish appropriate risk levels are being used determine the design basis loadings International peer reviews should be performed 19

20 Action to Assure Containment Integrity Establish containment venting levels which preclude pressures which could cause leakage Implement emergency response procedures including offsite or protected backup power and cooling water supply 20

21 Containment Design Detail Changes Allow for containment movements when subjected to temperatures anticipated during a severe accident Detail gaskets, flanges and bolting to prevent leakage above DBA conditions Containment capable of performing under severe accident conditions no matter the risk of an accident 21

22 Containment Structural Design Basis Section III Division 1 NE and Division 2 CC design basis approach should remain unchanged 22

23 Reactor Vessel Design Until a assessment of the three damaged reactor vessels is complete no changes should be contemplated 23

24 Summary Global initiatives are going forward to evaluate appropriate changes in design basis ASME/JSME cooperation is ongoing with review data review and comments on guidelines being considered Assessment of nuclear plant external design basis is ongoing world wide and updated Containment design details should address conditions when reactor core is failing to prevent containment leakage Emergency procedures being developed to respond to loss of power and cooling water conditions 24

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