A week at Fukushima
The timeline of events that put Fukushima in the world's spotlight
As we reach a week since Japan's devastating earthquake and tsunami, Utilities Middle East takes a look at the timeline of events that led to one of the world's worst-ever nuclear disasters.
Friday, March 11
A 9.0 magnitude earthquake 130km off the coast of north east Japan shakes the country and sends a destructive 10-metre-high tsunami tearing through coastal towns within the hour.
Initial reports of a cooling problem at TEPCO’s Fukushima Daiichi nuclear plant saw the government declare an emergency, and shortly after reporting no radioactive leakage TEPCO confirmed that water levels inside the plant were falling, and teams were working to restore power to the emergency system to avoid fuel rods being exposed to the atmosphere.
Saturday, March 12
A blast at the plant’s No1 reactor sends white smoke into the sky, and TEPCO quickly allays fears of a radiation leak, saying that while the roof and some of the outer walls of the reactor’s containment vessel had been destroyed, the primary containment vessel was still intact. Four workers are injured, as the government begins to evacuate resident in the vicinity of the Fukushima plant, and TEPCO starts to release pressure from the No1 reactor, leaking small amounts of radioactive material into the atmosphere.
Late evening, it is announced that seawater is being used in an attempt to cool the reactor core in No1, and that the water level in a second reactor is also falling.
Sunday, March 13
TEPCO begins venting air from reactor No3 as pressure continues to increase, then begins injecting boric acid-laced water into the core through a fire pump.
Monday, March 14
A hydrogen explosion at reactor No 3 injures seven people, while coolant levels in No2 continue to decrease. TEPCO say that the reactor’s containment vessel is still intact, but reveal that the cooling system in the No2 reactor has failed but that levels are still above the fuel rods.
Tuesday, March 15
An explosion and fire at the No4 reactor reveals that spent fuel rods, contained in a storage pool, may be burning, releasing radiation into the atmosphere. Readings show that radiation in the area is up to 400 millisieverts/hour, and residents up to 30km away are advised to stay indoors. Radiation levels are found to be a risk to human health.
Wednesday, March 16
Officials consider spraying water onto the reactors from helicopters, but the attempt is aborted amid fears over radiation levels and an unwillingness to disturb the air around the plant. A second fire at the No4 reactor is reported by a worker, but TEPCO reports no fire was present. However, the temperature in the spent fuel pool continues to rise.
Having evacuated all workers due to radiation concerns, later in the day teams were allowed back on to the site to supervise further emergency measures.
Thursday, March 17
The cooling operation is stepped up in an attempt to cool overheating fuel. Helicopters dump tonnes of seawater on the plant to try and prevent a meltdown, but with varied success. High radiation levels make the attempts risky, and pilots dump only four loads before leaving to minimise crew exposure.
Officials hope to restore power supply to the plant as soon as possible in order to activate electric pumps which will pour water into the reactors, as countries across the world urge their nationals in Japan to leave the country.