Update of the Fukushima Accident

Physical Events and Radiation Effects

Jay A. LaVerne Radiation Laboratory and Department of Physics

Japan International Workshop

Nuclear Engineering and Management School of Engineering University of Tokyo

1st Workshop March 9 and 10, 2011 2nd Workshop February 28 and 29, 2012 Update by Professor Sekimura

Overview of the Accident in Fukushima Daiichi Plant

Prof. Naoto Sekimura, Ph.D Vice Dean, School of Engineering Department of Nuclear Engineering and Management The University of Tokyo Outline

• The Earthquake and Tsunami on March 11 • The Accident in Fukushima Daiichi Nuclear Power Plants after the Earthquake and Tsunami on March 11 • Short Term and Long Term Issues • Status and Future of Nuclear Power Plants in Japan Earthquake Epicenter

Name: Tohoku Earthquake Magnitude: 9.0 Date/Time: Friday, March 11, 2011; 02:46:23 PM at epicenter Japan Depth: 32 km (19.9 miles) Distances: 129 km (80 miles) E of , Honshu, Japan 373 km (231 miles) NE of TOKYO, Japan Main and After Shocks of the March 11 Earthquake

Earthquake Research Institute, The University of Tokyo Tsunami Following the March 11 Earthquake

Compiled by 80 members from 33 organizations including The University of Tokyo: http://www.coastal.jp/ttjt/ Hesburgh Library: 66 m Fukushima Daiichi Nuclear Power Plants operated by TEPCO BWR with Mark-I Type Containment Vessel (Units 1-5)

Spent fuel pool Primary Containment Vessel (PCV) Reactor Pressure Vessel (RPV) Concrete shell drywell

Reactor Building

Wetwell “torus” Summary of Fukushima Daiichi Power Plants

* Typical operating pressure of PCV is 5 kPa, 1 atm = 101.4 kPa ** One emergency diesel generator is air cooled. Japan Nuclear Plant Locations

54 total Fukushima Plants Daiichi and Daini

Unit Type First criticality Electric power Reactor supplier

Fukushima I – 1 BWR-3 October 1970 460 MW General Electric

Fukushima I – 2 BWR-4 May 1973 784 MW General Electric

Fukushima I – 3 BWR-4 September 1974 784 MW

Fukushima I – 4 BWR-4 January 1978 784 MW

Fukushima I – 5 BWR-4 August 1977 784 MW Toshiba

Fukushima I – 6 BWR-5 March 1979 1,100 MW General Electric

Unit Type First criticality Electric power Reactor supplier

Fukushima II – 1 BWR-5 July 1981 1100 MW Toshiba

Fukushima II – 2 BWR-5 June 1983 1100 MW Hitachi

Fukushima II – 3 BWR-5 December 1984 1100 MW Toshiba

Fukushima II – 4 BWR-5 December 1986 1100 MW Hitachi Fuel Assembly in Mark-I Vessel Tsunami at Fukushima Daiichi Tsunami at Fukushima Daiichi Tsunami at Fukushima Daiichi

15:42:40 15:42:46 15:43:26 15:43:36

15:43:54 15:44:18 15:44:44 15:44:58

15:46:10

15.5 m above sea level

Source: Tepco Tsunami Effects at Fukushima Daiichi and Daini Sequence to Blackout Photographs from Fukushima 50

Source: Tepco Power Loss to Units 1-4 Power Loss to Units 5 - 6 Cooling of Unit 1 Loss of Water in Unit 1 Unit 1 Time Line Summary of Fukushima Daiichi Power Plants

* Typical operating pressure of PCV is 5 kPa, 1 atm = 101.4 kPa ** One emergency diesel generator is air cooled. Hydrogen Explosion Unit 1

March 12, 15:36 Simulation of Reactor Water Level and Temperature of Unit 1 Simulation of Reactor Core in Unit 1

Source: Tepco Simulation Summary of Damage to Unit 1 Cooling System of Unit 3 Cooling System of Unit 3 Simulation Summary of Damage to Units 2 and 3 Hydrogen Explosion in Unit 4 on March 15

Two leading causes: ZrO2 + H2O reaction or radiolytic production of H2 BWR with Mark-I Type Containment Vessel (Units 1-5)

Spent fuel pool Primary Containment Vessel (PCV) Reactor Pressure Vessel (RPV) Concrete shell drywell

Reactor Building

Wetwell “torus” Waste Storage in US

dry casks water pools

Yucca mountain Hydrogen Production by Radiolysis

- + H2O Ò eaq , H3O , OH, H, H2, H2O2

H2O

ionization

+ e- + H2O water excitation thermalization p r oton transfer (H O)* solvation 2 hydration (250-300 fs) (100 fs)

- + eaq H2 + O H + OH OH + H3O

G = 4.2 G = 0.3 G = 0.6 G = 4.2 molecules/100 eV

radical reactions (0.1 ns - 1µs) Reactivity of Zirconium

Above 1,500 K (2,240 °F)

Zr + 2 H2O → ZrO2 + 2 H2 This exothermic reaction, although only occurring at high temperature, is similar to that of alkaline metals (Na, K). Hydrogen Production by Zirconium Reaction Gas Treatment Systems for Units 3 and 4 Transfer of Gas from Unit 3 to 4

Source: Tepco Radiation Effects

Return of Godzilla? Effects of Different Doses

3.1 mSv/yr average in North America 10 mSv/yr in Denver 0.06 mSv chest x-ray 1.1 mSv CT scan 100 mSv/yr limit for inducing cancer 500 mSv leukemia, breast, bladder, colon, liver, lung, esophagus, ovarian, multiple myeloma, and stomach cancers 1000 mSv full body leads to radiation sickness 3500-5000 mSv full body LD50 in 30 days 50 mSv/yr for 5 years maximum for radiation worker Effects of Different Doses

LD50 in 30 days: solar flare event on moon, unshielded 35-50 Sv

0 1 2 3 4 5 6 7 8 9 10 Sv

estimated 3 yr dose leukemia, breast, bladder, colon, liver, lung, on Mars mission esophagus, ovarian, multiple myeloma, and stomach cancers: 500 mSV

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Sv radiation sickness Ramsar, Iran interplanetary space 200 mSv/yr 1 Sv

0 10 20 30 40 50 60 70 80 90 100 mSv Guarapari, Brazil DOE, NRC radiation safety limit for cancer induction 30 mSv/yr worker: 50 mSv/yr 100 mSv/yr

0 1 2 3 4 5 6 7 8 9 10 mSv

CT scan nature background USA Denver: chest x-ray 1.1 mSv 3.1 mSv/yr 10 mSv/yr 0.06 mSv

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 mSv round-trip New York DOE, NRC dose limit to Los Angeles: 0.037 mSv to public: 1 mSv/yr Average Annual Human Exposure to

Radiation source World USA Japan Remark

Inhalation of air 1.26 2.28 0.40 mainly from radon Ingestion of food & water 0.29 0.28 0.40 (K-40, C-14, etc.) Terrestrial radiation 0.48 0.21 0.40 depends on soil and building material Cosmic radiation 0.39 0.33 0.30 depends on altitude

sub total (natural) 2.40 3.10 1.50

Medical 0.60 3.00 2.30 mostly CT scans and nuclear medicine Consumer items - 0.13 cigarettes, air travel, building materials, etc.

Atmospheric nuclear testing 0.005 - 0.01 peak of 0.11 mSv in 1963 and declining since

Occupational exposure 0.005 0.005 0.01 US is mostly due to medical and aviation workers.[2]

Chernobyl accident 0.002 - 0.01 peak of 0.04 mSv in 1986 and declining since

Nuclear fuel cycle 0.0002 0.001 up to 0.02mSv near sites; excludes occupational exposure

Other - 0.003 Industrial, security, medical, educational, and research

sub total (artificial) 0.61 3.14 2.33

Total 3.01 6.24 3.83 millisievert per year Onsite Radiation Monitoring March 11 to 18

1 mSv/hr = 8760 mSv/yr 100 mSv/yr limit for inducing cancer 3500-5000 mSv full body LD50 in 30 days Onsite Radiation Monitoring March 11 to April 10

1 µSv/hr = 8.7 mSv/yr 3.6 mSv/yr average in North America Onsite Radiation Monitoring March 11 to October 17

1 µSv/hr = 8.7 mSv/yr 3.6 mSv/yr average in North America Radiation Dose in

1 µSv/hr = 8.7 mSv/yr 3.6 mSv/yr average in North America Integrated External Dose

0.06 mSv chest x-ray 1.1 mSv CT scan 500 mSv cancers Cesium Deposition April 29, 2011

Total release of Cs-137 6.0 x 1015 Bq

Total release of I-131 1.3 x 1017 Bq

International Nuclear Event Scale (INES) maximum 7 / major release > 1016 Bq Evacuation of Residents Radiation Monitoring of Workers Short Term Issues Addressed in First Year Initial Measures to Stabilize Damage Long Term Issues at Fukushima Erosion of Concrete in Unit 1 Reduction of O2 to Inhibit Radiation Corrosion Desalting of Spent Fuel Pools Desalting of Unit 4 Spent Fuel Pool U. S. Nuclear Regulatory Commission Response

Commissioner William C. Ostendorff

Overview of US reactors Stress on accident preparation Working with Japan U. S. Health and Human Services Response

C. Norman Coleman, MD

Team from National Cancer Institute, Health and Human Services, State Department and Pentagon Stress on accident preparation Working with Japan and lessons learned Future of Nuclear Power Japan Regulatory System Status of Reactors in Japan in Spring 2012 Status of Nuclear Power Plants in Japan Present Status of Nuclear Power Plants in Japan

Two reactors started up near Osaka Nuclear Regulation Authority replaced Nuclear Safety Commission TEPCO under government control Political Consequences for

National Elections on December 16 First national elections since Fukushima Democratic Party of Japan: Nuclear Free by 2030 Liberal Democratic Party: look at problem Tomorrow Party of Japan: Nuclear Free by 2020

Polls show most Japanese against nuclear power Epilogue

Japan Imports 84% of Energy Resources Pre Fukushima: 30% (48.9 GW) Nuclear Experienced Nuclear Free Summer - 9% shortage Local opposition is fierce against reactors Big economic and social impact – extreme conservation measures What next? Thank You