TOKYO, March 26 — Japan is stepping up its efforts to restore power and enhance cooling efficiency at the crisis-hit Fukushima Daiichi nuclear plant Saturday, but fears of contamination intensify as levels of radioactive materials are skyrocketing in the sea near the station.
Plant operator Tokyo Electric Power Co. has turned on the lights in the control room for the No. 2 reactor at the plant on the same day, while analyzing the water containing radioactive materials detected in the turbine building of the reactors and trying to remove the pools of water.
Meanwhile, abnormally high levels of radioactive materials have been found in the sea near the troubled plant, the government said, fanning concerns over fishery products in northeastern Japan.
The utility, known as TEPCO, said the radiation level at the No. 1 reactor of the plant has reached 200 microsieverts per hour, suspending work to pour seawater into its spent fuel pool. But its Fukushima office corrected the announcement later, saying no such high radiation level was detected.
Japan's top government spokesman Yukio Edano said at a press conference Saturday he finds it difficult to predict when the ongoing crisis at plant would end.
Asked about the prospects of the crisis, Edano said, "the current situation is that we are preventing it from worsening," adding that the situation still requires "an enormous amount of work" before it settles down.
Earlier in the day, radioactive iodine-131 at a concentration 1,250.8 times the legal limit was detected Friday morning in a seawater sample taken around 330 meters south of the plant, near the drain outlets of its troubled four reactors, the government's Nuclear and Industrial Safety Agency said.
The level rose to its highest so far in the survey begun this week, after staying around levels 100 times over the legal limit. It is highly likely that radioactive water in the plant has disembogued into the sea, the utility said.
Radioactive materials ''will significantly dilute'' by the time they are consumed by marine species, the agency said, adding that it will not have a significant impact on fishery products as fishing is not conducted in the area within 20 kilometers of the plant because the government has issued a directive for residents in the area to evacuate.
If people ingest 500 milliliters of water containing the same level of radioactive iodine, the radiation levels would reach the 1 millisievert limit which people can be safely exposed to in one year, the agency said.
TEPCO is planning to inject fresh water into pools storing the spent nuclear fuel at the plant to prevent crystallized salt from seawater already injected from forming a crust on the fuel rods and hampering the smooth circulation of water, thus diminishing the cooling effect. It has begun injecting fresh water into reactor containers of the No. 1 and No. 3 as well as No. 2.
At the same time, the firm is trying to remove the pools of water containing highly concentrated radioactive substances that may have seeped from either the reactor cores or the spent fuel pools.
On Thursday, three workers were exposed to water containing radioactive materials 10,000 times the normal level at the turbine building connected to the No. 3 reactor building. On Friday, a pool of water with similar high concentration of radioactive materials was found in the No. 1 reactor's turbine building, causing some restoration work to be suspended.
Similar pools of water were also found in the turbine buildings of the No. 2 and No. 4 reactors, measuring up to 1 meter and 80 centimeters deep, respectively. Those near the No. 1 and No. 3 reactors were up to 40 cm and 1.5 meters deep.
While it will try to analyze the radioactivity levels of the pools from the water found in the No. 2 and No. 4 reactors, TEPCO will remove such water in all four reactor units to reduce the risk of more workers being exposed to radioactive substances, said.
The risk hinders their efforts to restore the plant's crippled cooling functions, which are crucial to overcoming the crisis, the government's nuclear safety agency said. (PNA/Kyodo) scs/rsm