Eleven of Japan's nuclear reactors have automatically shut down,
following an 8.9 magnitude earthquake off its northeast coast,
according to the Japanese government.
The majority of the reactors belong to the Tokyo Electric Power Company (Tepco), which services the
capital and surrounding areas. It said that seven of its nuclear
units had shut down, affecting electricity supplies to more than
four million homes.
Because of the failure of the cooling system at Tepco's
Fukushima No 1 power plant, Japan has initiated emergency protocol. Nuclear fuel requires continued
cooling even after a plant is shut down because, even after
deactivation, the fuel elements are physically and radioactively
hot and therefore present a safety risk. Around 3,000 Residents
living within a two mile radius of the station were told to
Meanwhile the Tohuku Electric Power Company, which services northern Japan,
said three of its nuclear units had been stopped and that there was
a fire in a building at its Onagawa plant (but not one containing a
nuclear turbine). It is not clear at this stage which other nuclear
reactor -- bringing the total to eleven -- is closed.
A notice issued by the Japan Atomic Information Forum (JAIF) was
keen to point out that the Nuclear and Industrial Safety Agency
(Nisa) had said that no damage to the power plants had been
reported and there was no indication of radioactive release.
Meanwhile Tepco added in a statement: "At all the nuclear power stations, monitoring posts, which monitor
radiation through exhaust stacks have shown normal values. In other
words, at the present, no radiation leaks have been confirmed."
Whenever there is an incident (such as the failure of a cooling
system) occurs at a nuclear power plant, there is a clear procedure
that energy companies need to follow. They must first notify the
national Nuclear and Industrial Safety Agency. A minister from the
Ministry of Economy, Trade and Industry must the notify the prime
minister's office. The central nuclear emergency response
headquarters of the national government then issues a nuclear
emergency declaration, which includes instructions about
The International Atomic Energy Association (IAEA) says that it
is "seeking details on the situation at Fukushima and other nuclear
power plants and research reactors, including information on
off-site and on-site electrical power supplies, cooling systems and
the condition of the reactor buildings".
The quake hit the country around 250 miles north-east of Tokyo
at 14.46 local time. According to WSJ.com, some Tokyo residents knew about the earthquake before
it reached the city, thanks to an early warning system developed by
the country's meteorological agency and launched in 2007.
The system comprises of seismometers that detect the first
shockwave of an earthquake. It analyses this information to assess
how big the second, more destructive wave will be. If it's going to
be powerful, it sends a warning that appears on TV, radio and on
most mobile phones.
Earthquakes are rated according to the Japanese scale of 0-7.
There are three levels at each integer (for example, lower 6, 6 and
upper 6). Any quake that is predicted to be lower 5 or stronger
triggers the warning message. This means that some people far
away from the epicentre can have as much as 30 seconds warning
before the earthquake reaches them. However the message often
arrives too late for those nearby.
If you are worried about friends or family in Japan, you can
person finder or contact the UK Foreign Office on 0207 008