module 08 module 08fukushima dai-ichi accident 11.3.2011 1.3.2015 1.3.2015 vienna university of...
TRANSCRIPT
![Page 1: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/1.jpg)
Module 08Fukushima
Dai-ichi Accident 11.3.2011 1.3.2015
Vienna University of TechnologyAtominstituteStadionallee 2A-1020 Vienna, Austriaph: ++43-1-58801 [email protected]
![Page 2: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/2.jpg)
2
![Page 3: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/3.jpg)
Location of the NPPs near Earthquake Epicenter
(Tokai (I) is decommissioned)
Dai-ni
Dai-ichi
![Page 4: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/4.jpg)
Contribution of Dai-ichi NPPs to electric power production in Japan
• ~30% of Japanese electrical grid supplied by 54 reactor units: 30 BWRs / 24 Pressurized Water Reactors, (PWRs)
• ~17% of electrical grid supplied by the 30 BWRs
• ~2% of electrical grid was supplied by the 4 damaged BWRs at Fukushima Dai-ichi
![Page 5: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/5.jpg)
Fukushima Dai-ichi npp Status prior to Earthquake / Tsunami Event
Six Boiling Water Reactors (BWRs) at Fukushima Dai-ichi NPP
• Unit 1: 439 MWe, 1971 (in operation prior to event)
• Unit 2: 760 MWe, 1974 (in operation prior to event)
• Unit 3: 760 MWe, 1976 (in operation prior to event)
• Unit 4: 760 MWe, 1978 (shutdown prior to event)
• Unit 5: 760 MWe, 1978 (shutdown prior to event)
• Unit 6: 1067 MWe, 1979 (shutdown prior to event)
![Page 6: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/6.jpg)
Scram Levels
• Normal earthquake scram level: 0,15 g
• Design basis acceleration level: 0,45g, in this case all safety functions must stay operational
• Actual ground acceleration at site: 0,56 g - 20% above design basis
![Page 7: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/7.jpg)
Cross Section and Photo of GE Mark I(32 units world-wide, 23 in USA, 1 in Switzerland)
![Page 8: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/8.jpg)
Fukushima Dai-ichi NPPs
turbine buildings
cooling water discharge
![Page 9: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/9.jpg)
14.3.2011 9
![Page 10: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/10.jpg)
Loss of fuel tanks for emergency diesel generators
before tsunami
after tsunami
![Page 11: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/11.jpg)
Status upon Earthquake: March 11, 201111 operating reactors automatically shut‐down due to ground acceleration exceeding the reactor seismic trip settings
• Onagawa Units 1,2,3• Fukushima (I) Dai-ichi Units 1, 2, 3• Fukushima (II) Dai-ni Units 1, 2, 3, 4• Tokai (II) (Tokai (I) is decommissioned)
3 reactors were shutdown prior to earthquake for periodic inspection
• Fukushima Dai‐ichi Unit 4 (reactor was defuelled), Unit 5 and Unit 6
![Page 12: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/12.jpg)
Status upon Earthquake: March 11, 2011
• Many Japanese high rise elevators and the bullet trains also have seismic safety protection.
• No elevator accidents were reported.
• 27 bullet trains in north eastern Japan, reported to have activated emergency brakes, seconds before the earthquake hit, due to its early detection, preventing any derailing.
![Page 13: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/13.jpg)
Tsunami hits coast in Fukushima I
![Page 14: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/14.jpg)
Sea starts to overflow Tsunami wall at Dai-ni, (10 km from Dai-ichi site)
![Page 15: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/15.jpg)
Sea starts to overflow Tsunami wall at Dai-ni, (10 km from Dai-ichi site)
![Page 16: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/16.jpg)
1 minute later
16
![Page 17: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/17.jpg)
Non-nuclear facility damage: oil refinery fire, Ichihara, Chiba Prefecture
![Page 18: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/18.jpg)
Non-nuclear facility damage: oil refinery fire, Ichihara, Chiba Prefecture
Image credit dug spr — Home for Good
![Page 19: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/19.jpg)
Relative elevation of NPP systems
![Page 20: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/20.jpg)
Total loss of power
![Page 21: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/21.jpg)
Simplified view of BWR reactor vessel and containment design
DW: Drywell
WW: Wetwell
SFP: Spent Fuel Pool
SCSW: Secondary Concrete Sheild Wall
RPV: Reactor Pressure Vessel
Drywell: Bulb-shaped : 30 mm steel,
during operation filled with N2
Wetwell: Torus with about 3000 m3 cold
water
![Page 22: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/22.jpg)
![Page 23: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/23.jpg)
Normal Operation Emergency Cooling
![Page 24: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/24.jpg)
Fuel elements partially uncovered and start to heat up
Containement designed for 4 bars pressure exceeds 8 bars, pressure relief through relief valves
![Page 25: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/25.jpg)
Fuel storage pool damaged, water level decreases, fuel elements overheat are damaged and release fisson products
H2 explosion below reactor roof, release of fission products to the
environment
![Page 26: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/26.jpg)
Accident progression (summary only)
• Emergency battery power provided core cooling for about 8 hours (Unit 1), after which the batteries were discharged. Decay heat in the reactors and spent fuel ponds could no longer be removed
• Offsite power could not be restored, delays were encountered in obtaining and connecting portable generators
• Reactor temperatures increased, water levels in the reactor vessel decreased, eventually uncovering and overheating the Unit 1 core.
• Hydrogen was produced by oxidation of zirconium metal fuel cladding, zirconium-water reactions in core start above 1000ºC
![Page 27: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/27.jpg)
Accident progression (summary only)
• Spent fuel pool temperature rises in Unit 4 (containing all the reactor fuel), as water is lost from possible pool wall damage, 150 tons seawater pumped in, then fresh water pumped in.
• Unit 4 fire breaks out, April 11, that later extinguishes, with subsequent significant fire damage.
• April 2011 core damage status (subject to revision): Unit 1: 55%; Unit 2: 35%; Unit 3: 30%.
![Page 28: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/28.jpg)
Fuel assemblies: 4m long,About 60 rods per assembly
Block 1: ca 24 000 fuel rods(70 t Uran)
Block 2-4: ca 33 000 Fuel rods(95 t Uran)
![Page 29: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/29.jpg)
Spent Fuel PoolsDimensions in m
Num,ber ofFuel Assemblies
Heat input ifnotcooled
Depth in m
Unit 1 12 x 7 900
Unit 2 12 x 10 1240
Unit 3 12 x 10 1220
Unit 4 12 x 10 1590 appr. 3 MW
12*
* Above fuel top: 7m, after accident : - 5m** Evaporation: 100 m3 per dayNormal temperature: 30 C, max: 85 C
![Page 30: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/30.jpg)
GE-BWR Reactor Hall with Fuel Pool
![Page 31: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/31.jpg)
GE-BWR during revision
![Page 32: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/32.jpg)
![Page 33: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/33.jpg)
Decay Heat
3333
Nachzerfallswärme der Spaltprodukte
![Page 34: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/34.jpg)
Reactor decay heat problem
Decay heat after shutdown (Dai-ichi Units 2 and 3)
Unit 4 with over 1000 fuel rods in the spent fuel pool, the decay heat
could boil off about 100m3 of water per day, if the water was at boiling
point
Time Percentage of Full power Decay Heat MW_thermal
1 sec 7 % 167
1 day 1 – 2 % 47
1 year 0.2 % 5
![Page 35: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/35.jpg)
Reactor decay heat problem
• Radioactive isotopes (fission products) in the fuel produce radiation as they decay (gamma, beta, and alpha radiation)
• This decay radiation deposits most of its energy in the fuel (decay heat), about 7% of thermal power, immediately after a reactor is shutdown
• The decay heat must be removed at the same rate it is produced or the reactor fuel core will heat up and in the absence of any cooling the fuel may melt
• The removal of decay heat is performed by various cooling systems that provide water flow through the reactor core with the heat being transferred to heat exchangers and the ultimate heat sink of the sea.
• At Fukushima the integrity of the cooling systems was compromised by the tsunami and made it difficult for the operators to sustain decay heat removal
![Page 36: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/36.jpg)
Accident progression (summary only)
• Operators vented the reactor pressure vessel to relieve pressure, steam and hydrogen were discharged to primary containment (drywell), causing primary containment temperatures and pressures to rise
• Hydrogen explosions occurred (March 12, Unit 1: March 13, Unit 3: and March 15, Unit 2) while venting secondary containment, likely ignited by a sparks and hydrogen encountering free oxygen
• Hydrogen re-combiners, designed to burn vented hydrogen, did not operate probably because of power requirements
![Page 37: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/37.jpg)
Unit 1 Hydrogen explosion of outer secondary containment building
March 12, 2011
![Page 38: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/38.jpg)
March 14, 2011 Unit 3 Hydrogen explosion
![Page 39: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/39.jpg)
Hydrogen Explosion Unit 1 to 3, especially Unit 4
![Page 40: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/40.jpg)
![Page 41: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/41.jpg)
Emergency Actions
• Operating and emergency support staff used portable generators and portable pumps to inject seawater into the reactor vessels of and primary containments of Units 1, 2, and 3 via mobile fire trucks
• This had the effect of flooding the primary containment to cool the reactor vessel and any core debris that may have been released into primary containment.
• The seawater was the only cooling possibility but seawater effectively would render reactors unusable due to corrosion of fuel, coolant piping and reactor vessel, as well as leading to salt accumulation and clogging
![Page 42: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/42.jpg)
Emergency Actions
• A general emergency was declared in response to the initial events at Unit 1, with evacuation of public within 20-30 km of the plant: about 200,000 people evacuated
• Electrical power and cooling functions eventually restored, but much equipment is damaged and status unknown
• Offsite radiation and contamination, as a result of venting and the uncontrolled releases from hydrogen explosions and fires
• Potassium iodide pills distributed but not administered to public to minimize I-131 uptake in the thyroid
• Measures implemented to control affected contaminated food
![Page 43: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/43.jpg)
Summary of a Complex Accident
• All 13 effected Japanese NPP units withstood a massive earthquake, with likely minimal damage, but 4 units were overwhelmed by the tsunami
• Seawall was 5.7 m but the tsunami was 14 m (the design basis was underestimated)
• Significant reactor core fuel damage to 3 units (full meltdown predicted at Unit 1), damage to fuel in some fuel ponds (Unit 4 undamaged, Unit 3 damage due to explosions)
• Loss of site emergency diesel generators on site was key.
• 3 staff fatalities (explosion and heart attack), 15 injured by hydrogen explosions and tsunami
![Page 44: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/44.jpg)
Summary of a Complex Accident
• 1 indirect death, reportedly from suicide, of a local farmer after farming restrictions
• 4 hydrogen explosions in reactor buildings caused very significant structural and reactor equipment damage, fires in Unit 4
• 103 workers received doses over 100mSv, 6 of them between 309 and 678 mSv. The dose limit was first set to 250mSv, and reduced to 100mSv in August 2011
• 3 workers were hospitalized for severe burnings due to beta – radiation, they received doses around 180mSv
• A perspective on dose comparisons:
- 180 mSv is typical radiation dose to the bronchial tissue, from smoking 1.5 packs of cigarettes per day from polonium-210 inhalation, every two years, and
- One CT scan can give a dose of about 30 mSv
![Page 45: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/45.jpg)
Summary of a Complex Accident
• Over 200,000 people evacuated from the area, ground
contamination up to 50 km from site
• Huge Japanese economic and financial consequences
• Nuclear industry worldwide: future increased safety
vigilance and costs; international scrutiny (IAEA)
• Nuclear ‘renaissance’ projects worldwide now on hold or
being reviewed
• TEPCO has said it may take the rest of the year to bring the
plant back under control
• The world’s worst industrial accident (Bhopal) far exceeded
Fukushima in human toll, but likely not in economic
consequences
![Page 46: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/46.jpg)
Major Accident Contributors
• Underestimation of maximum earthquake
• Tsunami height• Location of safety related systems in
buildings (Diesel)• No backfitting of pressure relief pipes• No filters in pressure relief pipe• No H2 recombinators
![Page 47: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/47.jpg)
International Nuclear Event ScaleINES
![Page 48: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/48.jpg)
Contaminated Water in 2011
• 10 400m3 low active water released to the sea to increase capacity for high active water mainly from Unit 1+2
• Daily 1200m3 of high active water treated by filters ion-exchange and reverse osmosis
• Floating barge 136 m x 46 m to increase storage capacity
• 44 000m3 already treated, 100 000m3 still remains to be treated
![Page 49: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/49.jpg)
Contaminated Water in 2013Tepco Releases Contaminated Water Into Sea At Fukushima
• 1,130 tonnes of water below 30 (Bq/ℓ) of strontium-90 released, this is safety limit imposed by Japanese authorities
• Rainwater built up inside enclosure walls around clusters of tanks containing contaminated water that was used to cool damaged reactors.
• Recent leaks of contaminated water were reported on 19 August 2013, water was discovered inside and outside a dike surrounding one of the water tanks.
• The storage tanks were built following the March 2011 accident at the plant to hold radioactive water.
• An estimated 300 cubic metres of water escaped from one of the tanks, leaving “hot spots” of pools of radioactive water.
• The concentration of caesium-137 was 1.7 Bq/ℓ or less. The Ministry of Environment standard for public bathing is 10 Bq/ℓ.
• www.nsr.go.jp/english/data/F1_130917-1r.pdf
![Page 50: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/50.jpg)
Stresstests for NPPs
• Total loss of all power supply (extern, emergency diesel, batteries)
• Total loss of cooling capacity including spent fuel ponds
• Effects of earthquake on water environment (ocean, river, dams, hydrostations upstreams, mud slides)
• Human deficiencies• Aircraft crash and terrorist attacks considered
through other national security actions
![Page 51: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/51.jpg)
Stresstest Time Schedule
• Until Sept. 2011 all operators had to check their NPP according to the stresstest conditions
• They had to report to the National Regulatory Body which evaluated the results and reported to the EU commission by December 2011
• The EU Commission then recommended further steps to improve the safety of NPP‘s
• Web pages dedicated to public engagement: www.ensreg.eu/EU-Stress-Tests/Public-engagement
![Page 52: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/52.jpg)
Stress Tests: Participation
All 14 EUMember Statesthat operatenuclear powerplants, plus Lithuania,Switzerland,and Ukraine
![Page 53: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/53.jpg)
Stress Tests: Follow-up
• On October 4th 2012 the EC published its position on the stress tests
• Totally 145 NPPs have been analysed
• The risk analysis for earthquake and flooding should be based for all NPPs on the 10 000 year time frame
• On-site seismic instruments
• Containment filtered venting systems
![Page 54: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/54.jpg)
Stress Tests: Follow-up
• Equipment to fight severe accidents
• Backup emergency control room
• Nuclear insurance and liability should be harmonized in Europe
• The Commission intends to report on the implementation of the stress test recommendations in June 2014
• http://ec.europa.eu/energy/nuclear/safety/stress_tests_en.htm
![Page 55: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/55.jpg)
Conclusion
• Acivity release to the environment especially during explosions
• Depending on meteorology local short term increase of activity without reaching international emergency radiation limits outside NPP site
• Iodine pills distributed but not administered• Activity continuously measured by radiation network
both in air and seawater• No radiological short- or long term effects exspected • Cs-137 and I-131 were measured also in Austria with
high precision equipment (€ 150 000)
![Page 56: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/56.jpg)
What you should remember
• All operating NPPs were shut down by earthquake sensors without any damage
• The tsunami destroyed all possible power supply systems
• In this case core temperature increases rapidly and fuel elements were destroyed both in the core and in the spent fuel pool as no cooling was possible
• Mainly Iodine-131 and Cs-137 were released• Hydrogen explosion took place due to Zr-H2O reaction• No excessive overexposure of public• Four staff members were killed by mechanical accidents
![Page 57: Module 08 Module 08Fukushima Dai-ichi Accident 11.3.2011 1.3.2015 1.3.2015 Vienna University of Technology Atominstitute Stadionallee 2 A-1020 Vienna,](https://reader036.vdocuments.site/reader036/viewer/2022062407/56649d305503460f94a0873f/html5/thumbnails/57.jpg)
References
57
• http://online.itp.ucsb.edu/online/plecture/bmonreal11/ • http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300584349P.pdf• http://www.mext.go.jp.cache.yimg.jp/english/radioactivity_level/detail/
1303986.htm(=on-line radiation data in all provinces)• http://www.iaea.org/• M.Braun AREVA PPT vom 1.4.2011• R.Michel IRS, Leibnitz Universität Hannover• NucNet News in Brief No. 119 17th May 2011• NUCNET News in Brief• FORATOM NachrichtenOn-line Information• www.meti.go.jp/english/index.html• www.tepco.co.jp/en/index-e.html• www.grs.de• www.kit.edu