Radiation in water dumped on Fukushima plant may be rising

Japan’s government said the nuclear crisis at a quake-damaged power plant isn’t getting worse as radiation levels rise in sea water used to cool over-heating fuel rods.

“There’s no doubt we have been able to prevent the situation at the Fukushima Dai-Ichi plant from getting worse,” Chief Cabinet Secretary Yukio Edano said in Tokyo today. “The situation doesn’t permit us to loosen our grip.”

Tokyo Electric Power Co, the plant’s operator, started using pumps to drain water from the turbine building in the No 1 reactor and store it in tanks. Radiation readings of between 200 and 300 millisieverts per hour were found in water at the No 2 unit, Hidehiko Nishiyama, a spokesman at Japan’s Nuclear and Industrial Safety Agency, said today. That is equivalent to the maximum-permitted exposure for workers battling to contain the crisis. Repair work at the site of the worst nuclear disaster since Chernobyl has been hampered by explosions and radiation leaks. Tepco, as the utility is called, is studying how much water is in the No 2 and No 3 reactors before attempting to drain them.

Tepco switched on the lights in the control room of its No 2 reactor today, Vice President Sakae Muto said at a press conference in Tokyo. The utility turned on lights at its No 1 and No 3 reactors earlier this week.

Power cable
“We are not ready to comment on the schedule to turn on other facilities,” Muto said. “We need to connect a power cable to a cooling pump, which is located in the turbine housing where the water pool was found. We need to drain the water on the basement floor first.”

Muto said he can’t confirm that water from Tepco’s reactors is flowing into the sea.

The company is also starting to switch to fresh water for its cooling efforts of spent fuel rods and the reactor core to prevent further salt corrosion. Tepco stopped dousing sea water on a pool containing spent fuel rods in the No 1 reactor after radiation levels rose to 200 millisieverts per hour, Kyodo News reported, without citing anyone.

Tepco switched to using fresh water to cool the No 2 reactor at 10:10 am local time, and began draining excess water from turbine building of the No 1 unit, Muto said. The company is considering a similar operation on the No 2 and No 3 turbine houses, he said.

Radioactive nuclides including cesium-136 and yttrium-91 were found in water at the turbine building of No 1 reactor, the nuclear agency said in a statement on its website. Three workers were exposed to radiation on March 24 after stepping in water at the No 3 unit, which indicated a possible leakage from the reactor core, the agency said.

Iodine levels
Iodine levels measured in sea water close to the plant on March 25 were 1,251 times the legal limit, Nishiyama said. Those levels are not harmful to health, he said. Prime Minister Naoto Kan will appoint Sumio Mabuchi, a former land and transport minister, as an adviser on the nuclear crisis, Edano said. Mabuchi, 50, is a former engineer at Mitsui Construction Co.

Tepco plans to drain residual sea water after dumping almost 4,500 tons on the No 3 unit and 835 tonnes on No 4, according to government data. Fresh water may be used to cool the pool containing spent fuel rods at the No 3 and No 4 reactors tomorrow, Nishiyama said.