Nuclear Accident at Fukushima Daiichi NPP

A collection of images and data by Toro Laszlo

Member of the Council of the RSRPNational Institute of Public HealthRegional Centre of Public Health

Timisoara

Accident cause

•11/03/2011, 2:46 p.m. local time (7 hours earlier Romanian time) near the Japanese island of Honshu was an earthquake of 9 on the Richter scale.

•The quake had an impact on section of north-east coast of Japan where they are located a series of nuclear power plants (NPP).

•Nuclear reactors have been shut down properly.

NPP DAIICHI before the earthquake

Schema reactorului cu apa in fiebere al NPP DAIICHI

Remanent heat in DAIICHI NPP

Aszodi, 2011

Event description 12.03.• Units 4-6 in shut down status for periodic maintenance

and refuelling• Units 1-3 were stopped automatically after the quake• Reactor buildings and the containment successfully resist

to the earthquake• All reactor were dissconnected from the external AC

supply • Backup sources (diesel generators) started• At approximately one hour after the earthquake tsunami

hit the site– destroyed fuel tanks of the diesel generators– flooded the diesel generator building

(10m protection wall was not sufficient)• Mobile generators were sent to the site in a short time

but they ran out of fuel• Hydrogen Explosion Unit 1• Evacuation of population from the area of 20km Daiichi

NPP and 10km Daina NPP (approx. 200 000 person• On-site radioactivity increased

Event description 13.03.

• Lowering the internal pressure led to hydrogen explosion at unit 3

• Injection of sea water into the reactor vessel without cooling units at unit 1-3

• Variable on-site radioactivity• Increased radioactivity at

Onagawa NPP (north of Daiichi) revealed that comes from Daiichi NPP

Event description 14-15.03.

• Cooling with seawater stopped at Unit 2 (unknown cause), variable water level in the reactor

• Hydrogen Explosion at Unit 2• Cooling with sea water stopped at all units due to lack of fule

and water source• Fire then explosion in the spent fuel storage pool at unit 4

(relatively fresh fuel)• Restart seawater injection in the reactor wessel at all units• Significant radioactive emission• Housing on the area of 20-30 km• Risk of melting the core and damage of the containment at

Unit 2

Daiichi NPP after hidrogen explosion 15.03.

Daiichi NPP after hidrogen explosion 15.03.

Event description 16.03.

• Fire in spent fuel storage pool at Unit 4, cooling water evaporation

• Water level decrease at Unit 5, taking water from Unit 6

• Unsuccessfull attempts to feed with cooling water and boric acid the spent fuel storage pool at Unit 4

• Possible melting (at least partially, 50%) of the core at Units 1 and 3

• Fill with water the reactor vessel of the Unit 2

• Lowering water levels in the spent fuel pool at Units 3 and 4

• Increasing temperature in the spent fuel pool at unit 5 and 6

• Cooling with water canons from the police departement

Daiichi NPP after hidrogen explosion(16.03.)

Event description 17.03.

• Radioactivity observed outside of the site– Fukushima: 3-170 μSv / h (30 km from the NPP)– In two places increasing dose 80 to 170, and 26 to 95 μSv/h– Other directions 1-5 μSv/h

• Begining actions to connect a cable for AC supply to unit 2

• Continue attempts for cooling Unit 4 with water from helicopters (without succes) then with water canons

• One of the diesel generators from Unit 6 supplies Unit 5 for cooling spent fuel storage pool and the reactor wessel

Event description 18-19.03.

• An auxiliary transformer connected to external power source

• Actions to connect units 3 and 4 to AC power

• Actions to connect units 5 and 6 to AC power

• A backup generator from unit 6 repaired

• Continue seawater injection into the reactor vessel at Units 1-3

• Cooling unit 3 with water canons provided by police and fire departement units (civil defense, fire rescu units from Tokioand U.S. army), unit 3 is considered cooling enough

• Considering additional cooling the spent fuel pools from Unit 4

• At 5 AM, 19.03 starting pump C of the shutdown cooling system of unit 3, used to cool the spent fuel storage pool.

• Restart cooling Unit 4 with water cannons, in collaboration with civil defense.

Event description 20.03.

• Continue works connect to the power supply units 3 and 4.

• Continue cooling units 3 and 4with water cannons

• Continue filling the spent fuel storage pools

• Water injection is continued in reactor vessels of units 1-3

Event description 20-21.03

• Three holes are driven in the roof of reactor building units 5 and 6 to prevent hydrogen accumulation

• At around 15.55 light gray smoke is observed from the southpart of the 5th floor of Unit 3

• Parameters of the reactor vessel and containment are not change significantly

• Increase of radioactivity is subsequently found that returns to lower levels later

• For security reasons work is stoped and personnel withdraw from unit 3

• Smoke changing color to white and slowly disappears

• Ends connecting a cable from the main transformer of the temporary substation.

• It begins to restore power supply of units 3, 4, 5 and 6

• It restores the power supply from diesel generator of Unit 5

• March 21 the presence of radioactivity in seawater is detected near southern discharge channel near of the Daiichi NPP

• Cobalt, iodine and cesium is identified in seawater

Concentration in sea water (Bq/l)

  21.mar 22.mar

Co-58 59,5 16,7

I-131 5010 1190

I-132 2100 1360

Cs-134 149 150

Cs-136 213 235

Cs-137 148 153

Event description 22.03.

• Ends cable connecting the power supply to unit 2, the supply of of the entry side starts

• White smoke seen in Unit 2, until the morning of 22.03 it disappears

• White smoke at unit 3, disappears• Continue water cooling units 2, 3 and 4, at unit 4 a

concrete pumping device is used to fill the spent fuel storage pool

• Iodine and cesium is detected in the air at the site sampling points

Event description 23.03.

• Begins the injection of sea water in unit 2 using the normal cooling system

• Continue injecting sea water into unit 1 and 3

• The power supply of units 1-6 is restored, the main control rooms are connected to the AC supply

• It began work on restoring power supply of the systems of all units

• Continue injecting seawater in the spent fuel storage pool of units 3 and 4

• At 16.20, 23.03 a gray smoke is observed at unit 3, for security workers from the control room and around Unit 3 are evacuated

• Smoke changes in white and disappears slowly

• Subsequently found that radioactivity is increasing and decrease more slowly to the initial values

• End of water feed of the spent fuel storage pool of Unit 4

Green smoke at Unit 3 (23.03.)

Dose rates on the NPP site– sampling point MP6 (μSv/h)

Dose rates on the NPP site– sampling point MP4 (μSv/h)

Dose rates on the NPP site– sampling point MP1 (nSv/h)

Dose rates in Ibaraki prefecture (μSv/h)

0

1

2

3

4

5

6

7

1 15 29 43 57 71 85 99 113 127 141 155 169 183 197 211 225 239 253 267 281 295 309 323 337 351 365 379 393 407

Do

se

ra

te (

mic

roS

v/h

)

JAEA NS JAEA NF Tokyo University

Dose rates in prefectures (μSv/h)

0

0,1

0,2

0,3

0,4

0,5

0,6

17-1

8

0-1

7_8

14-1

5

21-2

2

4_5

11_1

2

18-1

9

1_2

8_9

15-1

6

22-2

3

5_6

12_1

3

19-2

0

2_3

9_10

16-1

7

23-2

4

6_7

13-1

4

20-2

1

3_4

10_1

1

Do

se r

ate

(mic

roS

v/h

)

Hokkaido(Sappro） Aomori（Aomori） Iw ate（Morioka） MIyagi（Sendai）Akita（Akita） Yamagata（Yamagata） Fukushima（Futaba） Ibaraki（Mito）Toshigi（Utsunomiya） Gunma（Maebashi） Saitama（Saitama） Chiba（Ishihara）Tokyo（Chinjyuku） kanagaw a（Chigasaki） Niigata（Niigata） Toyama（Imizu）Ichikaw a（kanazaw a） Fukui（Fukui） Yamanashi（Kohu） Nagano（Nagano）Gifu（Kakumuhara） Shizuoka（Shizuoka） Aichi（Nagoya） Mie（Yokkaichi）Shiga（Otsu） Kyoto（Kyoto） Osaka（Osaka） Hyogo（Kobe）nara（Nara） Wakayama（Wakayama） Tottori（Tohhaku） Shimane（Matsue）Okayama（Okayama） Hiroshima（Hiroshima） Yamaguchi（Yamaguchi） Tokushima（TokushimaKagaw a（Takamastu） Ehime（Matsuyama） Kochi（Kochi） Fukuoka（Dazaifu）Shiga（Shiga） Nagasaki（Ohmura） Kumamoto（Uto） Oita（Oita）Miyazaki（Miyazaki） Kagoshima（Kagoshima） Okinaw a（Uruma）

I-131 and Cs-137 in tape water (mBq/kg)

1

10

100

1000

10000

100000

18.03.2011 19.03.2011 20.03.2011 21.03.2011

Dri

nki

ng

wat

er (

mB

q/k

g)

Hokkaido I-131 Hokkaido Cs-137 Aomori I-131Aomori Cs-137 Iw ate I-131 Iw ate Cs-137Miyagi I-131 Miyagi Cs-137 Akita I-131Akita Cs-137 Yamagata I-131 Yamagata Cs-137Fukushima I-131 Fukushima Cs-137 Ibaraki I-131Ibaraki Cs-137 Tochigi I-131 Tochigi Cs-137Gunma I-131 Gunma Cs-137 Saitama I-131Saitama Cs-137 Chiba I-131 Chiba Cs-137Tokyo I-131 Tokyo Cs-137 Kanagaw a I-131Kanagaw a Cs-137 Niigata I-131 Niigata Cs-137Toyama I-131 Toyama Cs-137 Ishikaw a I-131Ishikaw a Cs-137 Fukui I-131 Fukui Cs-137Yamanashi I-131 Yamanashi Cs-137 Nagano I-131Nagano Cs-137 Gifu I-131 Gifu Cs-137Shizuoka I-131 Shizuoka Aichi I-131Aichi Cs-137 Mie I-131 Mie Cs-137Shiga I-131 Shiga Cs-137 Kyoto I-131Kyoto Cs-137 Osaka I-131 Osaka Cs-137Hyogo I-131 Hyogo Cs-137 Nara I-131Nara Cs-137 Wakayama I-131 Wakayama Cs-137Tottori I-131 Tottori Cs-137 Shimane I-131Shimane Cs-137 Okayama I-131 Okayama Cs-137Hiroshima I-131 Hiroshima Cs-137 Yamaguchi I-131Yamaguchi Cs-137 Tokushima I-131 Tokushima Cs-137Kagaw a I-131 Kagaw a Cs-137 Ehime I-131Ehime Cs-137 Kochi I-131 Kochi Cs-137Fukuoka I-131 Fukuoka Cs-137 Shiga I-131Shiga Cs-137 Nagasaki I-131 Nagasaki Cs-137Kumamoto I-131 Kumamoto Cs-137 Oita I-131Oita Cs-137 Miyazaki I-131 Miyazaki Cs-137Kagoshima I-131 Kagoshima Cs-137 Okinaw a I-131Okinaw a Cs-137

Fall out (kBq/m2)

0,00

20,00

40,00

60,00

80,00

100,00

18.08-19.03 19.08-20.03 20.08-21.03 21.08-22.03 22.08-23.03

fall

out (

kBq/

m2)

Hokkaido I-131 Hokkaido Cs-137 Aomori I-131 Aomori Cs-137 Iw ate I-131 Iw ate Cs-137

Miyagi I-131 Miyagi Cs-137 Akita I-131 Akita Cs-137 Yamagata I-131 Yamagata Cs-137

Fukushima I-131 Fukushima Cs-137 Ibaraki I-131 Ibaraki Cs-137 Tochigi I-131 Tochigi Cs-137

Gunma I-131 Gunma Cs-137 Saitama I-131 Saitama Cs-137 Chiba I-131 Chiba Cs-137

Tokyo I-131 Tokyo Cs-137 Kanagaw a I-131 Kanagaw a Cs-137 Niigata I-131 Niigata Cs-137

Toyama I-131 Toyama Cs-137 Ishikaw a I-131 Ishikaw a Cs-137 Fukui I-131 Fukui Cs-137

Yamanashi I-131 Yamanashi Cs-137 Nagano I-131 Nagano Cs-137 Gifu I-131 Gifu Cs-137

Shizuoka I-131 Shizuoka Aichi I-131 Aichi Cs-137 Mie I-131 Mie Cs-137

Shiga I-131 Shiga Cs-137 Kyoto I-131 Kyoto Cs-137 Osaka I-131 Osaka Cs-137

Hyogo I-131 Hyogo Cs-137 Nara I-131 Nara Cs-137 Wakayama I-131 Wakayama Cs-137

Tottori I-131 Tottori Cs-137 Shimane I-131 Shimane Cs-137 Okayama I-131 Okayama Cs-137

Hiroshima I-131 Hiroshima Cs-137 Yamaguchi I-131 Yamaguchi Cs-137 Tokushima I-131 Tokushima Cs-137

Kagaw a I-131 Kagaw a Cs-137 Ehime I-131 Ehime Cs-137 Kochi I-131 Kochi Cs-137

Fukuoka I-131 Fukuoka Cs-137 Shiga I-131 Shiga Cs-137 Nagasaki I-131 Nagasaki Cs-137

Kumamoto I-131 Kumamoto Cs-137 Oita I-131 Oita Cs-137 Miyazaki I-131 Miyazaki Cs-137

Kagoshima I-131 Kagoshima Cs-137 Okinaw a I-131 Okinaw a Cs-137

Possible dispersion of the cloud

Dose rates on the NPP site

Romanian situation• Radioactive cloud will not reach or will reach a very low concentration (m

or μBq/m3) due to long distance (high dilution)• From the event will not result a Chernobyl type contamination:

– Much lower emission time and intensity– Emission composition totally different, less a few orders of magnitude– Much greater distance

• There is a "crisis cell" at the regulator, CNCAN• Press release on the website of the Ministry of Health and the Romanian

Society of Radioprotection• The population is warning:

– Stable iodine administration is not necessary – Risks of stable iodine administration without medical suprevision

• There are no radiological risk for potential tourists to the Far East• Urgent measures are not necessary

Daiichi NPP one minute before explosion at Unit 3

Daiichi NPP three minutes after explosion at Unit 3

Infrared photos of Daiichi NPP