ID :
171404
Mon, 03/28/2011 - 21:34
Auther :
Shortlink :
https://oananews.org//node/171404
The shortlink copeid
Plutonium detected in soil at Fukushima nuke plant
TOKYO, March 29 Kyodo - Plutonium has been detected in soil at five locations at the crippled Fukushima Daiichi atomic power plant, Tokyo Electric Power Co. said Monday, adding to woes over radiation contamination in the country's worst nuclear crisis.
The operator of the six-reactor complex said that the plutonium, the presence of which was confirmed for the first time in the ongoing nuclear emergency, could have been discharged from nuclear fuel at the plant hit by the devastating March 11 earthquake and tsunami, but does not pose a major risk to human health.
Plutonium is more toxic than other radioactive substances such as iodine and cesium, but the levels confirmed from soil samples taken at the plant on March 21 and 22 were almost the same as those from the fallout detected in Japan following past nuclear tests by the United States and Russia, said the utility known as TEPCO.
The government's Nuclear and Industrial Safety Agency said it remains unknown which reactor plutonium came from and that TEPCO and the science ministry will strengthen monitoring on the environment both in the plant and outside of a 20-kilometer exclusion zone set by the government.
Hidehiko Nishiyama, a spokesman for the nuclear regulatory body, said the detection of plutonium suggests ''certain damage to fuel rods'' and said it is ''deplorable'' that the toxic radioactive material was found despite various containment functions at the reactors.
Meanwhile, TEPCO and the agency said Monday that high levels of radiation exceeding 1,000 millisieverts per hour were spotted Sunday in water in a trench outside the No. 2 reactor's building at the nuclear plant. They said the contaminated water is suspected to have come from the reactor's core, where fuel rods have partially melted.
The agency said TEPCO is expected to pump out similarly highly radioactive water that has been building up in the basement of the No. 2 reactor's turbine building, which is connected to the trench, in a bid to eventually remove the water.
TEPCO has found the concentration of radioactive substances in a pool at the No. 2 reactor's basement was 100,000 times higher than usual for water in a reactor core.
The company added the radiation level in the air in the trench stood at 100 to 300 millisieverts.
At a radiation level of 1,000 millisieverts per hour, people could suffer a decrease in the number of lymphocytes -- a type of white blood cell -- in just 30 minutes, and half could die within 30 days by remaining in such conditions for four hours.
Although it remains unknown whether the contaminated water has flowed into the sea from the trench that is 55 meters away from the shore, TEPCO suspects the high concentration of radioactive substances found in seawater near the plant reactors' drainage outlets may be linked to the trench water.
Earlier Monday, the nuclear agency said radioactive iodine-131 at a concentration 1,150 times the maximum allowable level was detected Sunday in a seawater sample taken around 1.5 kilometers north of the drainage outlets of the troubled Nos. 1-4 reactors.
Haruki Madarame, chairman of the Nuclear Safety Commission of Japan, a government panel, told reporters he is ''very worried'' about the high-level radiation found in water in the trench, which is outside the radiation-controlled area set by TEPCO.
Maradame said he cannot predict when the ongoing nuclear emergency will end and pointed to the possibility that fuel rods in the No. 2 reactor, which were temporarily exposed to the atmosphere, have been significantly damaged.
''We must control the water well so it won't ever go outside'' the complex, said Sakae Muto, vice president of TEPCO, at a news conference.
On Monday, TEPCO continued to remove highly radioactive water from inside reactor buildings at the crisis-hit plant, in an effort to enable engineers to restore the power station's crippled cooling functions. The turbine buildings are equipped with electric equipment necessary to cool down the reactors.
Nishiyama denied the possibility that the No. 2 reactor's vessel has cracks or holes, saying there is no data to suggest this. It is rather likely that radioactive water has leaked from pipes or valves, he said.
He said it is now necessary to strike a balance between two missions -- injecting coolant water into the reactor cores and spent nuclear fuel pools to prevent them from overheating, and removing radioactive water in the turbine buildings and trenches.
The spokesman said the water contamination may have been caused by operations to pour massive amounts of coolant water into the reactors and pools.
The operator of the six-reactor complex said that the plutonium, the presence of which was confirmed for the first time in the ongoing nuclear emergency, could have been discharged from nuclear fuel at the plant hit by the devastating March 11 earthquake and tsunami, but does not pose a major risk to human health.
Plutonium is more toxic than other radioactive substances such as iodine and cesium, but the levels confirmed from soil samples taken at the plant on March 21 and 22 were almost the same as those from the fallout detected in Japan following past nuclear tests by the United States and Russia, said the utility known as TEPCO.
The government's Nuclear and Industrial Safety Agency said it remains unknown which reactor plutonium came from and that TEPCO and the science ministry will strengthen monitoring on the environment both in the plant and outside of a 20-kilometer exclusion zone set by the government.
Hidehiko Nishiyama, a spokesman for the nuclear regulatory body, said the detection of plutonium suggests ''certain damage to fuel rods'' and said it is ''deplorable'' that the toxic radioactive material was found despite various containment functions at the reactors.
Meanwhile, TEPCO and the agency said Monday that high levels of radiation exceeding 1,000 millisieverts per hour were spotted Sunday in water in a trench outside the No. 2 reactor's building at the nuclear plant. They said the contaminated water is suspected to have come from the reactor's core, where fuel rods have partially melted.
The agency said TEPCO is expected to pump out similarly highly radioactive water that has been building up in the basement of the No. 2 reactor's turbine building, which is connected to the trench, in a bid to eventually remove the water.
TEPCO has found the concentration of radioactive substances in a pool at the No. 2 reactor's basement was 100,000 times higher than usual for water in a reactor core.
The company added the radiation level in the air in the trench stood at 100 to 300 millisieverts.
At a radiation level of 1,000 millisieverts per hour, people could suffer a decrease in the number of lymphocytes -- a type of white blood cell -- in just 30 minutes, and half could die within 30 days by remaining in such conditions for four hours.
Although it remains unknown whether the contaminated water has flowed into the sea from the trench that is 55 meters away from the shore, TEPCO suspects the high concentration of radioactive substances found in seawater near the plant reactors' drainage outlets may be linked to the trench water.
Earlier Monday, the nuclear agency said radioactive iodine-131 at a concentration 1,150 times the maximum allowable level was detected Sunday in a seawater sample taken around 1.5 kilometers north of the drainage outlets of the troubled Nos. 1-4 reactors.
Haruki Madarame, chairman of the Nuclear Safety Commission of Japan, a government panel, told reporters he is ''very worried'' about the high-level radiation found in water in the trench, which is outside the radiation-controlled area set by TEPCO.
Maradame said he cannot predict when the ongoing nuclear emergency will end and pointed to the possibility that fuel rods in the No. 2 reactor, which were temporarily exposed to the atmosphere, have been significantly damaged.
''We must control the water well so it won't ever go outside'' the complex, said Sakae Muto, vice president of TEPCO, at a news conference.
On Monday, TEPCO continued to remove highly radioactive water from inside reactor buildings at the crisis-hit plant, in an effort to enable engineers to restore the power station's crippled cooling functions. The turbine buildings are equipped with electric equipment necessary to cool down the reactors.
Nishiyama denied the possibility that the No. 2 reactor's vessel has cracks or holes, saying there is no data to suggest this. It is rather likely that radioactive water has leaked from pipes or valves, he said.
He said it is now necessary to strike a balance between two missions -- injecting coolant water into the reactor cores and spent nuclear fuel pools to prevent them from overheating, and removing radioactive water in the turbine buildings and trenches.
The spokesman said the water contamination may have been caused by operations to pour massive amounts of coolant water into the reactors and pools.
