High radiation has seeped into groundwater under the crisis-hit Fukushima nuclear plant, authorities said today, as Japanese and US 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 (TEPCO), said it has been checking underground water on the advice of the Nuclear Safety Commission of Japan.
It is 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 No.1 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 (SDF) 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.
