Nuclear Accident at Fukushima Daiichi NPP A collection of images and data by Toro Laszlo Member of the Council of the RSRP National Institute of Public Health Regional 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 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 person On-site radioactivity increased

Event description 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 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 km Risk of melting the core and damage of the containment at Unit 2

Daiichi NPP after hidrogen explosion

Event description 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 Radioactivity observed outside of the site –Fukushima: 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 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, 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 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 Three holes are driven in the roof of reactor building units 5 and 6 to prevent hydrogen accumulation At around 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.mar22.mar Co-5859,516,7 I I Cs Cs Cs

Event description 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 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 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, 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)

Dose rates in prefectures (μSv/h)

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

Fall out (kBq/m 2 )

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