Japanese media simmered with doubts yesterday about a government announcement that the world’s worst nuclear accident in 25 years had been contained with the tsunami-stricken Fukushima Dai-ichi nuclear power plant in a state of cold shutdown.
Japanese Prime Minister Yoshihiko Noda announced on Friday that the cold shutdown meant the accident had been contained, though he added that the government faced a long and hard task in cleaning up radiation and dismantling the plant, which could take up to 40 years.
The plant, 240km northeast of Tokyo, was wrecked by towering tsunami waves, triggered by a magnitude 9.0 earthquake on March 11, which knocked out its cooling systems, triggering meltdowns and mass evacuations.
A cold shutdown is when the water used to cool nuclear fuel rods stays below boiling point, preventing the fuel from reheating.
The declaration of a cold shutdown is a government pre-condition for allowing about 80,000 residents evacuated from a 20km radius exclusion zone around the plant to return home.
One of the chief aims of the plant’s operator, Tokyo Electric Power Co (TEPCO), had been to bring the reactors to that state by the end of the year.
However, critics have raised concern that Friday’s announcement was premature.
“Wouldn’t it be reasonable to declare containment had been achieved when radiation leaks have been brought to a complete halt?” asked an editorial in the -Nikkei Business Daily.
It said radioactive water continued to leak from the plant and that reactors No. 3 and No. 4 had yet to be covered to prevent leaks into the atmosphere.
Other newspapers echoed the skepticism over the crippled plant.
“Too soon to announce a containment,” read the headline of an editorial in the Asahi Shimbum, which said cold shutdown was merely a stage on the way to a resolution.
The Nikkei and others also took issue with the government’s characterization of the reactor’s status as “cold shutdown,” given that there was no way to directly measure the temperature of the melted fuel inside the reactors.
“It is like guessing the shape of a foot from the outside of the shoe,” the Nikkei said.
The Mainichi Shimbun agreed, saying efforts should be made to ascertain the condition of the melted fuel.
“It’s true that the situation is more stable than at the time of the accident,” the paper said. “But the term ‘cold shutdown’ refers to the suspension of a sound reactor.”
The government and TEPCO will aim to begin removing undamaged nuclear rods from the plant’s spent fuel pools next year. However, retrieval of fuel that melted down in the reactors may not begin for another decade.
The environmental group Greenpeace on Friday dismissed the announcement of a cold shutdown as a publicity stunt.
“By triumphantly declaring a cold shutdown, the Japanese authorities are clearly anxious to give the impression that the crisis has come to an end, which is clearly not the case,” Greenpeace Japan said in a statement.
However, Jonathan Cobb, an expert at the British-based World Nuclear Association, said the authorities had put in additional conditions before “cold shutdown conditions” were reached, including ensuring the release of radioactive material was under control.
“This criteria was also reached some time ago, the government has delayed declaration of cold shutdown conditions, one reason being to ensure the situation at the plant was stable,” Cobb said.