Engineers at the stricken Fukushima nuclear plant in north eastern Japan have brought the reactors into a “cold shutdown condition”, the Japanese prime minister Yoshihiko Noda confirmed today.
Reactors 1, 2 and 3 have been brought into a “cold shutdown condition” nine months following the massive earthquake and devastating tsunami, which caused a nuclear meltdown at the plant. Plant operator Tokyo Electric Power Company defined “cold shutdown” as lowering the coolant water temperature in the reactor to below 100°C while reducing pressure inside the reactor vessel to the same as the outside air pressue of 1kN/m².
Engineers have also brought the release of radioactive materials from the primary containment vessel within the nuclear reactor under control and radiation dose should not exceed 1 millisieverts (mSv) per year. Radiation dose reached 1,000mSv per hour at reactor 2 following the meltdown in March.
However, there remains a 20km exclusion zone around the plant and there are still no details on when engineers will be able to remove the nuclear fuel rods from the reactors.