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172286
Thu, 03/31/2011 - 18:36
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https://oananews.org//node/172286
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Radiation level in seawater hits new high near Fukushima plant
TOKYO (Kyodo) - In a sign that radiation is continuing to leak from the troubled Fukushima Daiichi nuclear power plant, radioactive iodine-131 at a concentration of 4,385 times the maximum level permitted under law has been detected in seawater near the plant, according to the latest data made available Thursday morning.
Japanese authorities were also urged to consider taking action over radioactive contamination outside the 20-kilometer evacuation zone around the plant, as the International Atomic Energy Agency said readings from soil samples collected in the village of Iitate, about 40 km from the plant, exceeded its criteria for evacuation.
The authorities denied that either situation posed an immediate threat to human health, but the government said it plans to enhance radiation data monitoring around the plant on the Pacific coast, about 220 kilometers northeast of Tokyo.
According to the government's nuclear safety agency, the concentration level of radioactive iodine-131 in a seawater sample collected Wednesday afternoon around 330 meters south of the plant exceeded the previous high recorded the day before. In Tuesday's sample, the concentration level was 3,355 times the maximum legal limit.
Hidehiko Nishiyama, a spokesman for the Nuclear and Industrial Safety Agency, acknowledged there is a possibility that radiation is continuing to leak into the sea, adding, ''We must check that (possibility) well.''
He reiterated that there are no immediate health concerns as fishing is not being conducted in the designated evacuation zone stretching 20 kilometers from the plant and radioactive materials will be diluted by the time seafood is consumed by people.
Still, the nuclear regulatory body said it has decided to add another three areas located 15 kilometers offshore for monitoring. It also plans to check underground water at the site.
An official of plant operator Tokyo Electric Power Co. said it is likely that the high level of contamination in seawater has been caused by water that has been in contact with nuclear fuels or reactors, but how it flowed to the sea remains unknown.
The No. 1, No. 2 and No. 3 reactors at the plant are believed to have suffered damage to their cores, possibly releasing radioactive substances, while the fuel rods of the No. 4 reactor kept in a spent fuel pool are also believed to have been exposed at one point, as the reactors lost cooling functions after the March 11 quake and tsunami.
In Vienna on Wednesday, Denis Flory, IAEA deputy director general and head of the agency's nuclear safety and security department, said readings from soil samples collected in Iitate ''indicate that one of the IAEA operational criteria for evacuation is exceeded'' there.
In response to the IAEA, Japan's Chief Cabinet Secretary Yukio Edano said Thursday the government may implement measures, if necessary, such as urging people living in the area to evacuate, if it is found that the contaminated soil will have a long-term effect on human health.
Nishiyama told a press conference in the afternoon that the agency's rough estimates have shown there is no need for people in Iitate to evacuate immediately under criteria set by the Nuclear Safety Commission of Japan.
''The radiation dose of a person who was indoors for 16 hours and outdoors for eight hours (and continued such a lifestyle) would be about 25 millisieverts, which is about half the level which requires evacuation based on the commission's criteria,'' he said.
In another effort to prevent radioactive dust from being dispersed from the plant, where masses of debris are strewn as a result of explosions, Tokyo Electric initially planned to conduct a test spraying of a water-soluble resin on Thursday, but postponed the plan due to rain.
An official said that rain would have slowed down the work and made it difficult to gauge the effects of the resin spraying.
The utility firm is considering when to conduct the work, at the south and west sides of the No. 4 reactor. A total of 60,000 liters will be sprayed over a period of two weeks.
Tokyo Electric also tried to remove contaminated water filling up some of the reactors' turbine buildings and tunnel-like trenches connected to them. But given the large amount of water, authorities are having difficulty finding places to store it.
The plant operator has been pouring massive amounts 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 amounts of radioactive materials into the environment.
However, the measure is believed to be linked to the possible leak of radiation-contaminated water from the reactors, where fuel rods have partially melted.
Removal of the water at the turbine buildings is believed to be essential to restoring the vital functions to stably cool down the reactors and the spent nuclear fuel pools.
On Thursday afternoon, a ship provided by U.S. forces carrying fresh water to cool down the reactors docked on the coast of the plant site to help the mission of water injection.
Japanese authorities were also urged to consider taking action over radioactive contamination outside the 20-kilometer evacuation zone around the plant, as the International Atomic Energy Agency said readings from soil samples collected in the village of Iitate, about 40 km from the plant, exceeded its criteria for evacuation.
The authorities denied that either situation posed an immediate threat to human health, but the government said it plans to enhance radiation data monitoring around the plant on the Pacific coast, about 220 kilometers northeast of Tokyo.
According to the government's nuclear safety agency, the concentration level of radioactive iodine-131 in a seawater sample collected Wednesday afternoon around 330 meters south of the plant exceeded the previous high recorded the day before. In Tuesday's sample, the concentration level was 3,355 times the maximum legal limit.
Hidehiko Nishiyama, a spokesman for the Nuclear and Industrial Safety Agency, acknowledged there is a possibility that radiation is continuing to leak into the sea, adding, ''We must check that (possibility) well.''
He reiterated that there are no immediate health concerns as fishing is not being conducted in the designated evacuation zone stretching 20 kilometers from the plant and radioactive materials will be diluted by the time seafood is consumed by people.
Still, the nuclear regulatory body said it has decided to add another three areas located 15 kilometers offshore for monitoring. It also plans to check underground water at the site.
An official of plant operator Tokyo Electric Power Co. said it is likely that the high level of contamination in seawater has been caused by water that has been in contact with nuclear fuels or reactors, but how it flowed to the sea remains unknown.
The No. 1, No. 2 and No. 3 reactors at the plant are believed to have suffered damage to their cores, possibly releasing radioactive substances, while the fuel rods of the No. 4 reactor kept in a spent fuel pool are also believed to have been exposed at one point, as the reactors lost cooling functions after the March 11 quake and tsunami.
In Vienna on Wednesday, Denis Flory, IAEA deputy director general and head of the agency's nuclear safety and security department, said readings from soil samples collected in Iitate ''indicate that one of the IAEA operational criteria for evacuation is exceeded'' there.
In response to the IAEA, Japan's Chief Cabinet Secretary Yukio Edano said Thursday the government may implement measures, if necessary, such as urging people living in the area to evacuate, if it is found that the contaminated soil will have a long-term effect on human health.
Nishiyama told a press conference in the afternoon that the agency's rough estimates have shown there is no need for people in Iitate to evacuate immediately under criteria set by the Nuclear Safety Commission of Japan.
''The radiation dose of a person who was indoors for 16 hours and outdoors for eight hours (and continued such a lifestyle) would be about 25 millisieverts, which is about half the level which requires evacuation based on the commission's criteria,'' he said.
In another effort to prevent radioactive dust from being dispersed from the plant, where masses of debris are strewn as a result of explosions, Tokyo Electric initially planned to conduct a test spraying of a water-soluble resin on Thursday, but postponed the plan due to rain.
An official said that rain would have slowed down the work and made it difficult to gauge the effects of the resin spraying.
The utility firm is considering when to conduct the work, at the south and west sides of the No. 4 reactor. A total of 60,000 liters will be sprayed over a period of two weeks.
Tokyo Electric also tried to remove contaminated water filling up some of the reactors' turbine buildings and tunnel-like trenches connected to them. But given the large amount of water, authorities are having difficulty finding places to store it.
The plant operator has been pouring massive amounts 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 amounts of radioactive materials into the environment.
However, the measure is believed to be linked to the possible leak of radiation-contaminated water from the reactors, where fuel rods have partially melted.
Removal of the water at the turbine buildings is believed to be essential to restoring the vital functions to stably cool down the reactors and the spent nuclear fuel pools.
On Thursday afternoon, a ship provided by U.S. forces carrying fresh water to cool down the reactors docked on the coast of the plant site to help the mission of water injection.
