Cold shutdown achieved at nuclear plant, Tokyo says

Dec 16, 2011, 11:51 GMT

Tokyo - A cold shutdown has been achieved at a Japanese nuclear plant damaged in an earthquake and tsunami after nine months of efforts to bring the facility under control, the government said Friday.

A cold shutdown means no nuclear reactions are occurring at the Fukushima Daiichi Nuclear Station, 250 kilometres north-east of Tokyo, and little radiation is leaking into the environment. It marks an end to the emergency phase of Japan's worst nuclear disaster and the start of the clean-up and scrapping of the reactors.

Prime Minister Yoshihiko Noda said that a 'major fear factor' had been eliminated with the cold shutdown.

The government said the announcement meant that the goal to achieve a cold shutdown by year's end had been achieved, but environmentalists criticized it as a deception of the public, saying the reactors were far from stable.

The March disaster caused the six-reactor plant's cooling systems to fail, allowing the fuel rods in reactors one and three to melt. Radioactive substances were released, leading to evacuations of residents living within 20 kilometres of the facility. They remained unable to return home.

To cool the reactors, workers sprayed them with water as they tried to get the cooling systems up and running again. The removal of that water, now contaminated, remains one of the biggest problems for the plants operator, the Tokyo Electric Power Co, or TEPCO.

Despite Friday's declaration, the government admitted this week that up to 40 years would be needed to decommission the power plant and clean up the area around it.

Government spokesman Osamu Fujimura said Friday that Tokyo planned to review the evacuation zones with local governments.

By the government's and TEPCO's definition, a cold shutdown occurs when the temperature of water used to cool nuclear fuel rods in the reactors' cores falls below boiling point.

Nuclear experts and environmental activists accused the government of erroneously using the technical term. 'To talk about a cold shutdown here borders on knowingly lying,' charged Reinhard Uhrig, a nuclear expert at the Austrian environmental group Global 2000.

Melted nuclear fuel rods have burned through the reactor floor and were lying in clumps at the bottom of the containment vessel, reaching estimated temperatures of more than 3,000 degrees, he said, adding that only by pumping in 22,000 litres of water per hour to cool the clumps was a meltdown being prevented.