Tokyo, March 13 (DPA) Radiation levels have surpassed legal limits at a quake-damaged nuclear power plant in northeastern Japan, officials said Sunday, raising concerns over radiation leaks.
Radiation at the Fukushima I plant was at 882 microsievert per hour and briefly topped 1,204 microsievert, top government spokesman Yukio Edano said. Japan allows an hourly exposure of 500 microsievert, which measures the biological effects of radiation.
Nuclear reactors at the Fukushima I and II plants lost their cooling functions after power and backup generators were cut off by a magnitude-8.9 earthquake Friday, operator Tokyo Electric Power Co. (TEPCO) said.
Engineers were in the process Sunday of releasing another dose of radioactive steam from a second reactor into the atmosphere, Edano said.
The technicians were working to prevent a meltdown of the reactor. According to Japanese news reports, the cooling water in the reactor has decreased so much that up to three metres of the fuel rods were exposed.
Fresh water has been injected into the cooling system of the number 3 reactor, Edano said. Radiation levels at that reactor were "very small and under control", he said.
TEPCO notified Japan's Nuclear and Industrial Safety Agency early Sunday that reactor number 3 had lost its cooling functions, making it the sixth reactor to do so since the quake hit.
On Saturday, an explosion destroyed part of the containment structure around reactor number 1 at the plant. TEPCO said the explosion was caused by water vapour. Technicians had begun to use seawater and boron to reduce pressure, releasing a cloud of steam containing radioactive elements such as caesium-137.
TEPCO said earlier Sunday on its website that the government had instructed it to reduce the pressure in the containment vessels of both reactors number 2 and 3 at the Fukushima I plant.
Some 200,000 people have been evacuated from a 20-km safety zone around the two plants, located 240 km north of Tokyo.
At least 19 people have been exposed to radiation, Kyodo said.