New readings show radiation levels continue to rise in the ocean outside a leaking nuclear plant in Japan’s north east, officials said today, as they debated whether to broaden the evacuation zone around the tsunami-damaged facility.
Japan’s Nuclear and Industrial Safety Agency (Nisa) said it was looking into a report from the United Nations atomic agency about high levels of radiation in the village of Iitate, 40km from the plant in Fukushima prefecture.
The International Atomic Energy Agency said the level in one spot tested in Iitate was twice its suggested threshold for evacuation.
Nisa spokesman Hidehiko Nishiyama said officials were checking radiation levels in the village, which lies outside even a voluntary evacuation area 31km from the plant. He said most residents had left, but about 100 chose to stay.
“We take it seriously,” he said. “We may consider asking these people to evacuate. But we need more time to study the situation.”
People in a 19km radius around the plant have already been ordered to leave their homes.
Experts say the spike does not pose an immediate danger to human health, but evacuation recommendations tend to be conservative to prevent long-term exposure to any elevation in radiation levels.
Operations continued today to cool down the dangerously overheated Fukushima Dai-ichi nuclear plant, which has leaked radiation after being damaged in the March 11 quake and tsunami.
The mission to stabilise the plant, 225km north east of Tokyo, has become more complicated since the discovery a week ago that radioactive water is pooling inside, restricting the areas in which crews can work.
It also puts emergency crews in the uncomfortable position of having to pump in more water to continue cooling the reactor while simultaneously pumping out contaminated water.
French nuclear officials who are experts of the removal of such radiation have recently arrived to help out, and the IAEA is also sending experts.
French president Nicolas Sarkozy was arriving in Tokyo today for talks with Japanese counterpart Naoto Kan. France currently holds the presidency of the Group of 20 leading world economies.
Contamination from the plant has been seeping into the sea, posing no threat to human health because fishing and swimming aren’t allowed in the vicinity but sparking concern about the continued leaks, Mr Nishiyama said.
However, radiation levels are rising. Seawater some 329m from the shore south of the plant measured 4,385 times the legal limit, up from 3,355 times the allowed amount the previous day, officials from plant operator Tokyo Electric Power Co (Tepco) said.
Experts say the radioactive particles are unlikely to build up significantly in fish, but the seafood concerns in the country that gave the world sushi are yet another blemish for Brand Japan.
Radioactive iodine is short-lived, with a half-life of just eight days, and in any case was expected to dissipate quickly in the vast Pacific Ocean. It does not tend to accumulate in shellfish.
Other radioactive particles have been detected in the waters near the plant, and some have made their way into fish. Trace amounts of radioactive cesium-137 have been found in anchovies as far afield as Chiba, near Tokyo, but at less than 1% of acceptable levels.