Japan: Radiation leaks to groundwater under N-plant

High radiation has seeped into groundwater under the crisis-hit Fukushima nuclear plant, authorities said on Friday, as Japanese and United States troops launched an intensive air and sea search for thousands of people who remained unaccounted for after the March 11 quake and tsunami.

The plant's operator, Tokyo Electric Power Company, said that it has been checking underground water on the advice of the Nuclear Safety Commission of Japan. It said the radioactive water was detected beneath the ground near the turbine buildings of five of the six reactors.

The remaining reactor, no 4, could not be checked because it was blocked by debris, national broadcaster NHK reported. TEPCO said that highly radioactive substances dispersed into the atmosphere may have seeped into the soil through rain and sprayed water, three weeks after the magnitude-9 quake and tsunami damaged the plant and left nearly 30,000 people dead or unaccounted for in the country's northeast.

The company will further analyse underground water and release the result later.  However, the Nuclear and Industrial Safety Agency said some of the analysis data on the groundwater presented by TEPCO cannot be trusted, casting doubts on findings that the concentration of radioactive iodine in the water was 10,000 times the legal limit.

It said the density readings of radioactive substances in groundwater samples taken on Tuesday and Wednesday from around the no1 reactor's turbine building may be revised downward, as TEPCO's evaluation programmes for materials such as tellurium, molybdenum and zirconium were found to have errors.

But, it said the firm's analysis programmes for radioactive iodine were confirmed to be correct. "TEPCO faces a grave situation as it is failing to live up to the expectations of people who are very worried by the company. Its data should be trustworthy," Hidehiko Nishiyama, a spokesman for the agency, was quoted as saying by Kyodo.

Earlier this week, TEPCO corrected its analysis of radiation levels in water accumulating in the basement of the no 2 reactor's turbine building. It had first described the radiation levels as 10 million times higher than normal before correcting the figure to 100,000 times.

Meanwhile, Japan's Self-Defense Forces and the US military launched a three-day intensive search for those still missing following the massive quake and tsunami. Using dozens of ships and helicopters, about 18,000 SDF personnel and 7,000 US military troops were involved in the operation along with members of police, Japan Coast Guard and fire departments.

The areas covered included shores that were largely submerged or remained under water and mouths of major rivers in Iwate, Miyagi and Fukushima prefectures, which were hit hard by the March 11 disaster, within about 18 km from the coastline.

The tsunami and earthquake have claimed at least 11,578 lives in 12 prefectures and left 16,451 people officially unaccounted for. Many of those who remained missing are believed to have been carried offshore after the tsunami struck the Pacific coast.

The search drive was timed to coincide with a spring tide, while efforts hit a snag in coastal areas that remained flooded. The tide, with waters ranging between high and low maximum, would make it easier to find victims when it ebbs. About 100 aircraft and 50 ships from the SDF were engaged in the operation, while the US military was participating with 20 aircraft and 15 ships.

Divers from the SDF, police, the coast guard and fire departments were also being mobilised, Kyodo said. However, the search would not be conducted within a 30-km radius of the troubled nuclear plant in Fukushima Prefecture, which is leaking radioactive materials into the environment, according to the authorities.

Prime Minister Naoto Kan said the government would set up a new task force on reconstruction work by April 11. He invited opposition party lawmakers to be part of the panel to cooperate in drafting measures necessary to rebuild the quake-ravaged region.

The premier also said the government would scrap some of the policies under the budget for fiscal 2011 to generate more money for reconstruction work. He said the first batch of an extra budget will be submitted to the Diet or Parliament by the end of this month.

Kan also said it is difficult to predict at this point when the crisis at Fukushima may end. The nuclear regulatory agency said it had issued another warning to TEPCO over the management of workers' radiation exposure at the plant, after it was found that there were not enough dosimetres to cover all of them.

Some workers were sharing dosimetres while doing the same job because many of the devices were destroyed in the March 11 quake and tsunami, a situation that was not "desirable from the viewpoint of ensuring workers' safety," Nishiyama said.

According to the nuclear safety agency, a total of 21 workers have been exposed to radiation exceeding 100 millisieverts so far during the ongoing crisis at the plant.

Workers, however, continued operations to secure enough space at tanks to store radiation-contaminated water that has been soaking the basements of the reactors' buildings and filling up tunnel-like underground trenches connected to them.

TEPCO has been pouring tonnes of water into the reactors and spent nuclear fuel pools at the plant as a stopgap measure to cool them down, because serious damage to fuel rods from overheating could lead to the release of enormous amount of radioactive materials into the environment.