The operator of Japan's crippled, leaking nuclear plant says two of the six reactor units are now safely under control after their fuel storage pools cooled down.
Tokyo Electric Power Company (TEPCO) declared Units 5 and 6 safe on Sunday night after days of pumping water into the reactors pool brought temperatures down.
Bringing the two units under control marks a minor advance in the efforts to stop the Fukushima Daiichi nuclear complex from leaking radiation. The two units are the least problematic of the six reactor units at the plant, which began overheating after the earthquake-triggered tsunami disrupted the plant's cooling systems.
Three hundred engineers have been struggling inside the danger zone to salvage the six-reactor Fukushima plant in the world's worst nuclear crisis since Chernobyl 25 years ago.
"I think the situation is improving step by step," Deputy Chief Cabinet Secretary Tetsuro Fukuyama told a news conference.
At the nuclear plant, workers braving high radiation levels in suits sealed in duct tape managed to connect power to the No 2 reactor, crucial to their attempts to cool it down and limit the leak of deadly radiation.
TEPCO officials said the workers aimed to restore the control room function, lights and the cooling at the No 1 reactor, which is connected to the No 2 reactor by cable.
Police said they believed more than 15,000 people had been killed in Miyagi prefecture, one of four in Japan's northeast that took the brunt of the tsunami damage. In total, more than 20,000 are dead or missing, police said.
The unprecedented crisis will cost the world's third-largest economy up to quarter of a trillion dollars. Economics Minster Kaoru Yosano put the economic damage at above 20 trillion yen ($248 billion), which was his estimate of the total economic impact of the 1995 earthquake in Kobe.
Encouragingly for Japanese transfixed on work at the Fukushima complex, the most critical reactor - No 3, which contains highly toxic plutonium - stabilized after fire trucks doused it for hours with hundreds of tons of water.
"We believe the water is having a cooling effect," a TEPCO official said.
Workers aim to reach the troubled No 4 on Monday or Tuesday. If successful, that could be a turning point in a crisis rated as bad as United State's 1979 Three Mile Island accident.
If not, drastic measures may be required such as burying the plant in sand and concrete, as happened at Chernobyl in 1986, though experts warn that could take many months and the fuel had to be cooled first.
(中国日报网英语点津 Helen 编辑)
Todd Balazovic is a reporter for the Metro Section of China Daily. Born in Mineapolis Minnesota in the US, he graduated from Central Michigan University and has worked for the China Daily for one year.