The Disaster in Japan: A brief timeline

- Tiana Bouma

On March 11, 2011 an 8.9 magnitude earthquake struck off the east coast of Honshu, Japan and has turned into the most expensive natural disaster in the world’s history. The earthquake, subsequent tsunami, and following nuclear power plant issues have created over $300 billion dollars in costs and stolen the lives of 27,000 individuals.

One of the largest issues Japan has faced is the prevention of potential nuclear power plant meltdowns. The overload of news reports and information on the disaster made it hard for me to sort through exactly what was happening, when, and where. So I decided to make a timeline so that maybe others who feel the same can have a better idea of the day-by-day events going on in Japan.

Timeline

March 11 - Four nuclear plants closest to the earthquake were safely shut down.

• Heightened state of alert declared for Fukushima-Daiichi plant.
• Tsunami flooding disabled diesel generators intended to provide back-up electricity to plant’s cooling system.
• Fire at Onagawa plant extinguished.

March 12 - Evacuation of residents living within 20 km of Fukushima Daiichi plant (about 170,000 people) and residents living within 10 km of Fukushima-Daini plant (about 30,000 people).

• Explosion at Unit 1 reactor of Fukushima-Daiichi primary containment vessel and four workers injured, outer shell of containment was lost.

March 13 - Fukushima-Daini units 1, 2, and 4 retain off-site power and unit 3 is in a safe, cold shutdown.

• Three workers injured in various ways at Fukushima-Daiichi.
• One worker is exposed to higher-than-normal radiation levels at Fukushima-Daiichi.

March 14 - Hydrogen explosion at Unit 3 reactor at Fukushima-Daiichi plant.

• Six people injured and the reactor building exploded but the PCV wasn’t damaged.

March 15 - Fukushima-Daini, Onagawa, and Tokai nuclear power plants are in safe and stable shutdown.

• Explosion at Unit 2 reactor at Fukushima-Daiichi.
• Spent fuel storage pond at Unit 4 was on fire and radioactivity was directly released into atmosphere.
• 6.1 earthquake in Eastern Honshu, Japan.

March 16 - Fire at reactor 4 at Fukushima-Daiichi.

March 17 -

• Radiological contamination – Nine TEPCO employees and eight subcontractor employees suffered from deposition of radioactive material to their faces.
• One worker suffered significant exposure during “vent work” and was transported to an off-site center.
• Two policemen exposed to radiation were decontaminated and firemen who were exposed are under investigation.
• At Fukushima-Daiichi unit 4 remains major safety concern.

March 18 - At Fukushima-Daiichi plant, workers opened holes in the roofs of Units 5 & 6 to prevent possible accumulation of hydrogen.

March 19 - Japanese Ministry of Health, Labor and Welfare confirmed presence of radioactive iodine contamination in food products in Fukushima Prefecture.

• Containment vessel pressure indication was restored for Unit 1 at Fukushima-Daiichi.

March 20 - Units 5 & 6 at Fukushima-Daiichi plant are in cold shutdown and stable.

March 22 - High levels of radioactivity in food, notably spinach, in samples taken from 37 places in five cities south of Fukushima site.

• Distribution of food restricted.
• TEPCO detected radioactive materials in seawater near southern discharge canal at the Fukushima-Daiichi plant.

March 23 - AC power available to Units 1, 2, and 4, power restored to instruments in all units except 3.

• Pressure in reactor pressure vessel and drywell if Unit 3 is stable.
• Radiation dose rate at Daiichi decreased.
• Ministry of Health, Labor, and Welfare encouraged Ibaraki and Chiba Prefecture to monitor seafood products.
• No significant risk to human health was verified.

March 24 - Three workers at the Fukushima-Daiichi plant were exposed to elevated levels of radiation.

• Two workers hospitalized for treatment of severely contaminated feet had been working for about 3 hours in contact with contaminated water.

March 25 - Unit 1 is reported as stable by Japanese authorities.

• Work is underway for the recovery of lightning and instrumental systems on the common spent pool.
• Milk is restricted in Fukushima and Ibaraki Prefectures.
• Certain vegetables are restricted in four prefectures (Fukushima, Ibaraki, Tochigi, and Gunma).

March 26 - Fresh water has replaced seawater to cool the reactor pressure vessels at Units 1, 2, and 3 at Fukushima plant.

March 27 - Earthquake of 6.5 magnitude of coast of Honshu.

March 28 - Radioactivity in environment, food, and water is a matter of concern and there is a need for further comprehensive monitoring.

March 29 - Accumulated contaminated water found in trenches close to turbine buildings of Units 1-3.

March 31 - Unit 1 condenser is full and pumping water from the turbine-building basement to the condenser has been stopped.

• The Russian Federation, Ireland, and Switzerland reported detection of very small amounts of radiation in the air, not of any radiological concern.

April 1 - Food restrictions placed.

• Fukushima: Distribution and consumption of leafy vegetables and unprocessed raw milk.
• Ibaraki: Distribution of spinach, kakina, parsley, and unprocessed raw milk.
• Gunma: Distribution of spinach and kakina.
• Tochigi: Distribution of spinach and kakina.

April 2 - Water in the condenser storage tank of Unit 1 was transferred to surge tank of the suppression pool and water in the trench was transferred to a water tank at central environmental facility main building.

• There was a crack in sidewall of pit of Unit 2 reactor and water was leaking directly into the sea.

April 3 - A second US Navy barge arrived carrying fresh water to be transferred to a “filtered water tank”.

• Concrete poured and polymer injected to prevent leak in wall of Unit 2 reactor.
• Units 1, 2, and 3 switched to external power supply.

April 4 - Leakage in Unit 2 Turbine building has not stopped.

• Discharged 11,500 tons of low level radioactive water from Fukushima-Daiichi plant into sea.
• Plan to release 10,000 tons of water from a waste treatment facility and 1,500 tons from drainage pits around reactors 5 & 6 and the operation was planned to last around 5 days.

April 5 - Leak of highly contaminated water from cable storage pit in Unit 2 was stopped due to measures taken by workers.

April 6 - Power is available to instrumentation in Unit 3 and TEPCO authorized to begin injection of nitrogen into PCV of Unit 1 at Fukushima plant.

April 7 - 7.1 magnitude earthquake in Japan, epicenter 20 km away from Onagawa nuclear power plant.

April 8 - Food restrictions in four prefectures (Fukushima, Ibaraki, Tochigi, and Gunma) and in certain locations in Chiba prefecture continue.

April 10 - In units 1, 2, and 3 of Fukushima Daiichi plant 60,000 tons of contaminated water was removed from turbine buildings and trenches.

• Temporary storage tanks ordered to provide additional capacity for water.

April 11 – 6.6 magnitude earthquake in Japan, epicenter 68 km from Daiichi nuclear power plant.

April 17 & 18 - An unmanned robot was used to conduct inspections of the Reactor Buildings in Units 1, 2 and 3.

April 22 – Area within 20 km of Fukushima Daiichi nuclear power plant is announced as a no entry zone.