Groundwater near the crippled Fukushima No. 1 nuclear power plant was confirmed contaminated with radiation for the first time.
Officials of Tokyo Electric Power Co., the plant operator, said Thursday that water taken from a groundwater discharge facility near the building housing the No. 1 reactor contained iodine-131 about 10,000 times the acceptable levels.
Referring to the detection of contaminated groundwater, Chief Cabinet Secretary Yukio Edano said on Friday, "We will have to conduct proper monitoring of the effects on seawater and the surrounding regions."
Government officials were also planning to strengthen checks for radiation contamination of groundwater and the ocean.
Highly contaminated water believed to have leaked from the reactor cores has already been detected in concrete trenches within the plant grounds.
While a connection is still not clear, the detection of contaminated groundwater could mean that highly radioactive water from the reactor cores has leaked outside of the plant site.
TEPCO officials said the contaminated water was taken from a facility that discharges water to a ditch after groundwater has been pumped up from a depth of about 15 meters.
The pumps are located around the reactor building and designed to prevent the building from moving due to the buoyancy of the groundwater.
A water sample taken Wednesday from the discharge facility detected iodine-131 with a radiation level of 430 becquerels per cubic centimeter.
Officials of the Nuclear and Industrial Safety Agency asked TEPCO to check into the type and amount of radioactive material found in the water. TEPCO is now reanalyzing the water samples.
TEPCO officials did not deny the possibility of a connection between the groundwater and the contaminated water found in the basements of the turbine buildings of the reactors.
However, it is possible that radioactive substances emitted from the Fukushima plant dispersed into the atmosphere and returned to the ground as rainfall.
After the March 11 Great East Japan Earthquake, the pumps removing groundwater stopped operating so groundwater has not been flowing directly into the ocean through the discharge ditch.
Sources said the possibility was low that the groundwater would leak into the ocean and raise radiation levels in seawater to the level detected Thursday.
Seawater near the Fukushima No. 1 nuclear plant has been found contaminated with iodine-131 at 4,385 times greater than the acceptable levels.
The science ministry has expanded measurement points to up to about 30 kilometers off the coast from the Fukushima No. 1 plant and continues to check the water at the surface and seabed.
On March 23, surface water was found to have iodine-131 about twice the acceptable levels at a point about 30 km off the coast. On Wednesday afternoon, water from about 10 km off the coast was also found to have iodine-131 at twice the acceptable levels.
While iodine-131 is normally not found near the seabed, levels about one-fourth the acceptable standards have been detected.
Meanwhile, TEPCO officials on Friday began spraying synthetic resins using a sprinkler truck within the Fukushima plant grounds to prevent the spread of dust containing radioactive materials. The water-soluble resin is used in civil engineering work and creates a film when it dries.
Officials said the resin could contain the dust for between six months to a year.
Work also began on Friday to pump in fresh water to tanks within the Fukushima plant from U.S. military ships.
Officials of Tokyo Electric Power Co., the plant operator, said Thursday that water taken from a groundwater discharge facility near the building housing the No. 1 reactor contained iodine-131 about 10,000 times the acceptable levels.
Referring to the detection of contaminated groundwater, Chief Cabinet Secretary Yukio Edano said on Friday, "We will have to conduct proper monitoring of the effects on seawater and the surrounding regions."
Government officials were also planning to strengthen checks for radiation contamination of groundwater and the ocean.
Highly contaminated water believed to have leaked from the reactor cores has already been detected in concrete trenches within the plant grounds.
While a connection is still not clear, the detection of contaminated groundwater could mean that highly radioactive water from the reactor cores has leaked outside of the plant site.
TEPCO officials said the contaminated water was taken from a facility that discharges water to a ditch after groundwater has been pumped up from a depth of about 15 meters.
The pumps are located around the reactor building and designed to prevent the building from moving due to the buoyancy of the groundwater.
A water sample taken Wednesday from the discharge facility detected iodine-131 with a radiation level of 430 becquerels per cubic centimeter.
Officials of the Nuclear and Industrial Safety Agency asked TEPCO to check into the type and amount of radioactive material found in the water. TEPCO is now reanalyzing the water samples.
TEPCO officials did not deny the possibility of a connection between the groundwater and the contaminated water found in the basements of the turbine buildings of the reactors.
However, it is possible that radioactive substances emitted from the Fukushima plant dispersed into the atmosphere and returned to the ground as rainfall.
After the March 11 Great East Japan Earthquake, the pumps removing groundwater stopped operating so groundwater has not been flowing directly into the ocean through the discharge ditch.
Sources said the possibility was low that the groundwater would leak into the ocean and raise radiation levels in seawater to the level detected Thursday.
Seawater near the Fukushima No. 1 nuclear plant has been found contaminated with iodine-131 at 4,385 times greater than the acceptable levels.
The science ministry has expanded measurement points to up to about 30 kilometers off the coast from the Fukushima No. 1 plant and continues to check the water at the surface and seabed.
On March 23, surface water was found to have iodine-131 about twice the acceptable levels at a point about 30 km off the coast. On Wednesday afternoon, water from about 10 km off the coast was also found to have iodine-131 at twice the acceptable levels.
While iodine-131 is normally not found near the seabed, levels about one-fourth the acceptable standards have been detected.
Meanwhile, TEPCO officials on Friday began spraying synthetic resins using a sprinkler truck within the Fukushima plant grounds to prevent the spread of dust containing radioactive materials. The water-soluble resin is used in civil engineering work and creates a film when it dries.
Officials said the resin could contain the dust for between six months to a year.
Work also began on Friday to pump in fresh water to tanks within the Fukushima plant from U.S. military ships.
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