Fukushima-Daiichi, Hurricane Sandy: NRC Standards vs. NFIP Regulations June 9-14, 2013

Transcription

1 Fukushima-Daiichi, Hurricane Sandy: NRC Standards vs. NFIP Regulations June 9-14, 2013

2 TOPICS A brief comparison of Fukushima-Daiichi and Sandy Flooding Events at other Nuclear Power Plants NRC Actions post Fukushima Overview of Flood Hazard Analysis and U.S. Nuclear Power Plant Licensing Comparison of NFIP Standards vs. NRC Regulations 2

3 Fukushima-Daiichi

4 Fukushima-Daiichi 6 Reactor site one of 15 largest in the world designed and sited in 1960 s. Two additional reactors were planned 3/11/ Earthquake and Tsunami 3 units were shutdown for maintenance Remaining Reactors were shut down automatically after earthquake Off-site power was lost due to Earthquake - Emergency Generators were pumping cooling water 4

5 Fukushima-Daiichi So far so good but then Tsunami hit Protective Seawall designed to 5.7 Meters Tsunami Height reported at Meters This disabled Emergency Generators lost ability to cool reactors Partial meltdowns of 3 reactors subsequent explosions of hydrogen gas further damaging spent fuel pools. Other backup generators available on higher ground Switch-gear was flooded 5

6 Fukushima-Daiichi Nearby Fukushima Daini Plant 9 Meter Tsunami seawater pumps failed External Power maintained Reactors were shutdown Nearby Onagawa Plant Shut down at earthquake per procedure 14 meter seawall no Tsunami damage although nearby town destroyed Nearby Tokai Plant Shut down at earthquake per procedure 5 meter tsunami 6 meter seawall 6

7 Sandy

8 Sandy Sandy made Landfall approximately midnight 10/29 10/ $Billions in damages --- 8/12 ft. surge heights in NJ/NY Oyster Creek Nuclear Power Plant 30 miles north of Sandy Landfall Indian Point NPP 130 Miles north/ Salem and Hope Creek 60 miles west Oyster Creek 7 ft. surge Plant in maintenance Outage Intake Structure Flooded with 7 ft. storm surge/vs. 10 ft. design level Backup Generators activated to provide cooling water Indian Point 10 ft. surge 1 unit shut down due external Grid failure Others remained on line. Salem/Hope Creek no impact 8

9 Other Flooding Incidents

10 Flooding at other Nuclear Plants Fort Calhoun Nebraska Missouri River Flooding 2011 Plant was in a planned shutdown -Plant was protected Mishap with punctured rubber berm Nearby Cooper Nuclear Station had no issues higher ground 1999 Blayais Nuclear Power Plant flood France 3/4 unit operating Two were automatically shut down. Although no mishaps occurred issues with procedures were identified. Changes to Flooding evaluation standards 10

11 NRC Reaction to Fukushima

12 NRC Reaction to Fukushima-Daiichi Near-Term Task Force The NTTF Charter, dated March 30, 2011, tasked the NTTF with conducting a systematic and methodical review of NRC processes and regulations and determining if the agency should make additional improvements to its regulatory system. Developed comprehensive Recommendations addressing areas including: Flooding Seismic Flex Strategy Spent Fuel Pool Instrumentation Hardened Vents Emergency Planning 12

13 NRC Reaction to Fukushima-Daiichi NRC issued a Request for Information March, 2012 Required all Plant Operators to provide specific information relative to NTTF Recommendations for Flooding/Seismic/Emergency Planning Flooding Recommendations Recommendation 2.3: Conduct detailed plant inspections to determine if plant is adequately protected against the flood events used for the Current License Basis. Recommendation 2.1: Hazard Reevaluation Report Reevaluate all flooding hazards at the site using present day regulatory guidance. Most U.S. Plants were licensed pre-1985 Standards and methodologies have evolved Integrated Assessment If reevaluated hazard exceeds current license basis determine what actions should be taken to address the increased hazard 13

14 Regulatory Comparison

15 NRC and Flooding - Basics NRC regulations DO NOT require that plants be protected from flooding by elevation or structural means NRC regulations DO require that plants be able to achieve and maintain a safe shutdown during flooding conditions. NRC requires evaluation of many flooding sources Local Intense Precipitation Flooding from Rivers and Streams Dam Breaches and Failures Storm Surge and Seiche Tsunami Ice Jams Channel Migration or Diversion Combined Effects 15

16 NRC vs. NFIP - Flood Mechanisms Flooding Mechanism NRC NFIP Comments Local Intense Precipitation Yes? Similar to Shallow Flooding Flooding in Rivers and Streams Yes Yes Dam Breaches and Failures Yes No Storm Surge Yes Yes Seiche Yes Some NRC evaluates on more water bodies Tsunami Yes No Ice Jams Yes Yes Channel Migration Yes No Combined Effects Yes Some NFIP evaluates surge+wave, NRC evaluates more combinations 16

17 NRC vs. NFIP Design Event Flooding Mechanism NRC NFIP Local Intense Precipitation A PMP event on local site 100-year Flooding in Rivers and Streams A PMP event in watershed 100-year Dam Breaches and Failures Overtopping/Seismic/Sunny Day N/A Storm Surge Probable Maximum Hurricane 100-year Seiche Probable Maximum Seiche 100-year Tsunami Probable Maximum Tsunami N/A Ice Jams Probable Maximum Event 100-year Channel Migration Effects of most severe credible event No Combined Effects Varies but generally aimed at a 10-6 event 100-year 17

18 Summary

19 NRC Standards NRC looks at much lower probability events than NFIP Sounds like a good idea right? Potential Issues Science regarding low probability events not as well developed Conflicts with other regulatory agencies Dam Failure 19

20 Wrap up Should I worry about the Local Nuclear Power Plant? 20

21 Wrap up Should I worry about the Local Nuclear Power Plant? Design Standards are high Low probability events Multiple Hazards evaluated Protection features have been recently inspected 21

22 Wrap up Should I worry about the Local Nuclear Power Plant? 22

23 Wrap up Should I worry about the Local Nuclear Power Plant? How can I sleep at night when I know that: Plant design basis may be over 50-years old NRC feels the need to reevaluate flood hazards 23

24 Questions?