Fukushima & Three Mile Island Reactor Accidents: Recovery, Cleanup, Lessons, & Future Foundation For Nuclear Studies Congressional Briefing May 18, 2012 Lake H. Barrett [email protected]Disclaimer: Fukushima Information is preliminary especially regarding interpretation of events; opinions expressed are mine and mine alone. Most Photos Courtesy of TEPCO 1 L. Barrett Consulting LLC
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Fukushima Three Mile Island Reactor Accidents: Recovery ......Fukushima & Three Mile Island Reactor Accidents: Recovery, Cleanup, Lessons, & Future Foundation For Nuclear Studies Congressional
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Fukushima & Three Mile Island Reactor Accidents: Recovery, Cleanup, Lessons, & Future
• Pre‐accident Water Processed and Released to Make Room For Accident Water
• Accident Water Never Released to River
• Airborne Iodine Releases From Auxiliary Building Mitigated
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Recovery Cleanup Actions
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Building Remediation to Gain Core Access (Barrett Entry)
Phased Unique Air and Water Cleanup Systems Created Based on Best Available
Technology
TMI Damaged Core Removal~1985‐1990
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TMI Defueling Sequence
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Core Bore Machine Defuel Can Loading Can Transfers
Core Debris StorageTransportShipping Cask
TMI Unit 1 Restarted• Restarted September 18, 1985
– Six and Half Year Process
– Extensive Operator Training
– Plant Modifications
– Extensive Public Regulatory Hearing Process
• One of Best Operating Reactors Today in US
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Three Mile Island History• Reactor Scram: 04:00 3/28/79• Core melt and relocation: ~ 05:00 – 07:30 3/28/79• Hydrogen Deflagration: 13:00 3/28/79 • Recirculation Cooling: Late 3/28/79• Phased Water Processing: 1979‐1993:Removed ~1.2MCi Cs137• Containment Venting 43KCi Kr‐85: July 1980• Containment Entry: July 1980• Reactor Head removed and core melt found: July 1984• Start Defuel: October 1985• Shipping Spent Fuel: 1988‐1990• Finish Defuel: Jan 1990• Evaporate ~10 M Liters Processed Water: 1991‐93• Cost: ~$1 Billion (YOE)
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Peace On The RiverMost Painful Experiences Are the Most Teachable
We Learned & We Changed
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20081978
Most Stress is Gone- All are WiserNuclear Power is SaferNuclear Power is More Productive
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Fukushima Daiichi Nuclear Power Station
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Units 5 &6
Dry SNF Storage
CommonSpent Fuel Pool
Units 1‐4
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Event Initiation
March 11, 2011•About 14:46, a 9.0 magnitude earthquake struck (Plant design basis earthquake: 8.2)‐ Plant safety systems reportedly function satisfactorily.
•Units 1,2 & 3 Scram & Unit 4 has 100 day old core offloaded into Unit 4 Spent Fuel Pool
•~ 15:45, Seven tsunami waves up to 14 meters high inundated the site, whose design basis was 5.7 meters – the reactors and backup diesel power sit roughly 10 to 13 meters above sea level
•The tsunami & earthquake impacts up and down the northeast coast resulted in tragic loss of 20,000+ lives, damage, and destruction of infrastructure.
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Subduction Fault
No Known Seismic Safety DamageDespite Huge Earthquake, Seismic Loads Close to Design
Safety Systems Appeared Functional
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Tsunami Waves
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Incoming Wave Behind Reactor Building 15:42
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Wave Behind Reactor Building 15:43:26
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Wave Behind Reactor Building 15:43:54
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Wave Behind Reactor Building 15:44:58
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Wave Behind Reactor Building 15:47
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Tank Top 15M
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Tsunami Size: Main Safety Factor 3/11 15:45
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GE Mark I Reactor Building
Spent Fuel Pool
Reactor Vessel
Suppression Pool (Torus)
Primary Containment
Steel Containment Vessel
Secondary Containment
Boiling Water Reactor DesignAt Fukushima Daiichi
Refueling Floor
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Browns Ferry Primary Containment
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Post Tsunami U 1‐4 Conditions (~15:45)
• No AC Power
• No Unit 1 & 2 DC & Partial Unit 3 DC Power
• No Control room Lighting (flashlights)
• Salt Water Flooded EDGs & Switchgear
• Salt Water Destroyed Service Water Pumps & Switchgear
Sampling Indicates Little If Any Fuel DamageLow Cesium Levels in 90Bq/mlWater Level Lowered For Seismic Safety
Unit 4 Explosion: H2 From Unit 3
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Unit 4
Unit 3
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Dry Storage Cask Facility
air inlet
overhead travelling crane
storage cask
transport vehicle
cask trolley
RelativeLow Elevation
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Body: γ-ray shield (carbon steel)
outer shellprimary lid
secondary lid
basket(borated-aluminum alloy)
cask frame
neutron shield(boron-added resin)
bottom plate
Main featuresCylindrical forged carbon-steel casksSimilarity with transport casks5-115T 52 Assy Casks & 4-96T 37 Assy CasksHelium filledSteel for γ-ray shield/ resin for neutron shieldBorated-aluminum alloy basket for sub-criticality
Storage Only Metal Cask
Dry Storage Facility Was Flooded But All 9 Casks Intact
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Fukushima Stabilized
• Established Recirculation Core Cooling– Damaged Pressure Vessel(s) & Containments
• Mitigating Airborne Releases
• Mitigating Water Releases
• Gaining Building Access to Start Recovery Activities
• Managing Solid Wastes
• Maintain Personnel Safety: High Rad Areas
• Addressing Evacuation Zone Situation L. Barrett Consulting LLC 59
Units 1‐4 After U4 Building Explosion 3/16
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Unit 4 Fuel Pool‐Side
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Unit 3 & Unit 4
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Water Spray to Unit 3 Pool Area
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Unit 4 Reactor Building Water Injection Boom To Spent Fuel Pool