ID :
175703
Fri, 04/15/2011 - 19:29
Auther :
Shortlink :
https://oananews.org//node/175703
The shortlink copeid
Radioactivity in water dumped from Fukushima plant lower than thought
TOKYO, April 15 Kyodo - The total level of radioactive materials in water dumped in the sea from the crippled nuclear power plant in Fukushima Prefecture earlier this month was lower than previously estimated, the nuclear safety agency said Friday.
But the Nuclear and Industrial Safety Agency instructed the operator of the plant, Tokyo Electric Power Co., to study in more detail the impact on the marine environment of the move, which sparked concern among neighboring countries.
As the nation's worst nuclear crisis drags on more than a month after it was triggered by the March 11 earthquake and tsunami, small amounts of plutonium have been detected for the third time in soil samples taken at the six-reactor Fukushima Daiichi complex, the plant operator said.
Also Friday, the operator, known as TEPCO, said it will pay up to 1 million yen to each of the roughly 50,000 households within 30 kilometers of the plant whose residents have been forced to evacuate their homes or remain indoors, as provisional compensation for the damage caused by the crisis.
According to the safety agency, TEPCO released 10,393 tons of water containing a total of 150 billion bequerels of radioactive materials from the plant into the Pacific Ocean between April 4 and 10.
The operator, which earlier projected that the readings could reach 170 billion bequerels, said it had not detected any substantial changes in the levels of radioactive materials in seawater sampled off the plant's shore and farther offshore since the release.
The release of contaminated water sparked concern among China, South Korea and Russia over the possible impact on marine life and the environment, with Seoul complaining that it had not been notified in advance.
Meanwhile, the Atomic Energy Society of Japan said it believes that nuclear fuel inside troubled reactors at the plant has partially melted and settled in granular form at the bottom of pressure vessels.
But the academic body's panel on nuclear energy safety has said data suggest the melted fuel at the plant's damaged Nos. 1 to 3 reactors has been kept at a relatively low temperature.
The panel also said that the fuel grains with a diameter of between several millimeters and 1 centimeter are believed to have settled evenly at the bottom of the vessels, leaving almost no possibility of a nuclear chain reaction called ''recriticality.''
A large buildup of melted nuclear fuel could transform into a molten mass so hot that it could damage the critical containers and eventually leak huge amounts of radioactive materials.
TEPCO reported its third detection of plutonium in soil samples taken March 31 and April 4 at the nuclear complex in Fukushima Prefecture. The samples had levels of plutonium around the same as those observed in Japan following past nuclear bomb tests abroad.
Workers continued their efforts to bring the reactors under control and stop radioactive leaks from the coastal plant, continuing the injection of nitrogen gas into the No. 1 reactor to prevent hydrogen explosion and installing more steel plates near a seawater intake for the No. 2 reactor.
TEPCO threw three sandbags each containing 100 kilograms of zeolite, a mineral that absorbs radioactive materials, into the sea near the plant on Friday to reduce the levels of contamination.
Spokesman Hidehiko Nishiyama said his agency is also considering injecting nitrogen into the two other troubled reactors soon.
The agency also said the top level of water in the vertical part of a tunnel connected to the No. 2 reactor had risen back Friday morning even though the utility pumped out around 660 tons of highly radioactive water from the tunnel.
Removing the highly contaminated water that has flooded the basements of the Nos. 1 to 3 reactor turbine buildings and adjacent tunnels is seen as key to restoring critical cooling systems for the damaged reactors, which were lost in last month's disasters.
But the Nuclear and Industrial Safety Agency instructed the operator of the plant, Tokyo Electric Power Co., to study in more detail the impact on the marine environment of the move, which sparked concern among neighboring countries.
As the nation's worst nuclear crisis drags on more than a month after it was triggered by the March 11 earthquake and tsunami, small amounts of plutonium have been detected for the third time in soil samples taken at the six-reactor Fukushima Daiichi complex, the plant operator said.
Also Friday, the operator, known as TEPCO, said it will pay up to 1 million yen to each of the roughly 50,000 households within 30 kilometers of the plant whose residents have been forced to evacuate their homes or remain indoors, as provisional compensation for the damage caused by the crisis.
According to the safety agency, TEPCO released 10,393 tons of water containing a total of 150 billion bequerels of radioactive materials from the plant into the Pacific Ocean between April 4 and 10.
The operator, which earlier projected that the readings could reach 170 billion bequerels, said it had not detected any substantial changes in the levels of radioactive materials in seawater sampled off the plant's shore and farther offshore since the release.
The release of contaminated water sparked concern among China, South Korea and Russia over the possible impact on marine life and the environment, with Seoul complaining that it had not been notified in advance.
Meanwhile, the Atomic Energy Society of Japan said it believes that nuclear fuel inside troubled reactors at the plant has partially melted and settled in granular form at the bottom of pressure vessels.
But the academic body's panel on nuclear energy safety has said data suggest the melted fuel at the plant's damaged Nos. 1 to 3 reactors has been kept at a relatively low temperature.
The panel also said that the fuel grains with a diameter of between several millimeters and 1 centimeter are believed to have settled evenly at the bottom of the vessels, leaving almost no possibility of a nuclear chain reaction called ''recriticality.''
A large buildup of melted nuclear fuel could transform into a molten mass so hot that it could damage the critical containers and eventually leak huge amounts of radioactive materials.
TEPCO reported its third detection of plutonium in soil samples taken March 31 and April 4 at the nuclear complex in Fukushima Prefecture. The samples had levels of plutonium around the same as those observed in Japan following past nuclear bomb tests abroad.
Workers continued their efforts to bring the reactors under control and stop radioactive leaks from the coastal plant, continuing the injection of nitrogen gas into the No. 1 reactor to prevent hydrogen explosion and installing more steel plates near a seawater intake for the No. 2 reactor.
TEPCO threw three sandbags each containing 100 kilograms of zeolite, a mineral that absorbs radioactive materials, into the sea near the plant on Friday to reduce the levels of contamination.
Spokesman Hidehiko Nishiyama said his agency is also considering injecting nitrogen into the two other troubled reactors soon.
The agency also said the top level of water in the vertical part of a tunnel connected to the No. 2 reactor had risen back Friday morning even though the utility pumped out around 660 tons of highly radioactive water from the tunnel.
Removing the highly contaminated water that has flooded the basements of the Nos. 1 to 3 reactor turbine buildings and adjacent tunnels is seen as key to restoring critical cooling systems for the damaged reactors, which were lost in last month's disasters.
