ID :
201980
Wed, 08/17/2011 - 19:06
Auther :
Shortlink :
http://m.oananews.org//node/201980
The shortlink copeid
Fukushima plant leaking less radioactive material: TEPCO
TOKYO, Aug. 17 Kyodo - Tokyo Electric Power Co. said Wednesday the amount of radioactive substances leaking from the crippled reactors at the Fukushima Daiichi nuclear power plant has declined over the past month, but stopped short of declaring that one of the conditions to achieve a cold shutdown has been cleared.
The data was included in the latest version of a road map to contain the nuclear crisis. It left unchanged the time frame to stabilize the reactors by January and highlighted a need to train and deploy experts on radiation dose management.
According to the plant operator TEPCO, the amount of radioactive substances leaking from the Nos. 1, 2 and 3 reactors dropped to a maximum 200 million becquerels per hour, from 1 billion becquerels per hour a month earlier.
The figure means that a person could be exposed to up to 0.4 millisievert when standing around the plant for one year, below the government-set reference limit of 1 millisievert per year.
The public exposure dose, in addition to the temperature of the reactors, is a key factor for judging whether the crisis-hit plant has achieved a state of cold shutdown. But TEPCO and government nuclear safety agency officials said the accuracy of the estimates of exposure dose is ''rough.''
At a joint press conference with TEPCO, nuclear disaster minister Goshi Hosono said improving the functioning of water decontamination facilities at the plant is a ''major challenge'' toward achieving a cold shutdown.
Restoration efforts moved onto the ''step 2'' phase of the road map in July, after TEPCO and the government declared the ''step 1'' goals of stably cooling the damaged reactors and reducing the radiation dose around the site had been achieved.
Completing the step 2 phase was estimated to take a further three to six months.
A senior government official who attended the press conference did not narrow down the time range, leaving uncertain when residents of areas around the plant can put their lives back in order.
Hit by a magnitude-9.0 earthquake and massive tsunami on March 11, the Fukushima nuclear plant lost nearly all its power sources, and consequently the ability to cool the reactors and spent fuel pools at the Nos. 1 to 4 units. The buildup of heat and gas inside subsequently led to a series of explosions which badly damaged three of the reactors.
TEPCO has created a new system that removes radioactive substances from polluted water accumulating inside the plant and recycles the decontaminated water to cool the crippled reactors. But the water processing system has been plagued with problems and its operating rate has averaged just 69 percent since the system began operating in June, according to TEPCO.
As radioactive polluted water is created by injecting water into the damaged reactors, it is important to reduce the amount of water accumulating within the plant so that it does not overflow, Hosono said.
Hosono also said the government plans to start from September experimental projects on cleaning the radiation-contaminated areas outside the plant before implementing full-scale decontamination such as within a 20-kilometer radius of the plant designated as a no-entry zone.
During the press conference, TEPCO showed a video that delivered a message from Masao Yoshida, head of the Fukushima power plant, who apologized for causing great inconvenience amid the world's worst nuclear crisis since the 1986 Chernobyl disaster.
It was the first time that TEPCO made Yoshida's voice public since the nuclear crisis. In the video, available on TEPCO's website, he expressed gratitude for ''warm'' messages of support received from in and outside the country.
Yoshida drew media attention over his decision to continue injecting seawater into one of the troubled reactors in the early days of the crisis as an emergency step, despite an order to suspend the injection, at one point suspected to be coming from Prime Minister Naoto Kan.
The company issued a warning to him for falsely reporting the facts, although his decision was widely seen to be appropriate.
The data was included in the latest version of a road map to contain the nuclear crisis. It left unchanged the time frame to stabilize the reactors by January and highlighted a need to train and deploy experts on radiation dose management.
According to the plant operator TEPCO, the amount of radioactive substances leaking from the Nos. 1, 2 and 3 reactors dropped to a maximum 200 million becquerels per hour, from 1 billion becquerels per hour a month earlier.
The figure means that a person could be exposed to up to 0.4 millisievert when standing around the plant for one year, below the government-set reference limit of 1 millisievert per year.
The public exposure dose, in addition to the temperature of the reactors, is a key factor for judging whether the crisis-hit plant has achieved a state of cold shutdown. But TEPCO and government nuclear safety agency officials said the accuracy of the estimates of exposure dose is ''rough.''
At a joint press conference with TEPCO, nuclear disaster minister Goshi Hosono said improving the functioning of water decontamination facilities at the plant is a ''major challenge'' toward achieving a cold shutdown.
Restoration efforts moved onto the ''step 2'' phase of the road map in July, after TEPCO and the government declared the ''step 1'' goals of stably cooling the damaged reactors and reducing the radiation dose around the site had been achieved.
Completing the step 2 phase was estimated to take a further three to six months.
A senior government official who attended the press conference did not narrow down the time range, leaving uncertain when residents of areas around the plant can put their lives back in order.
Hit by a magnitude-9.0 earthquake and massive tsunami on March 11, the Fukushima nuclear plant lost nearly all its power sources, and consequently the ability to cool the reactors and spent fuel pools at the Nos. 1 to 4 units. The buildup of heat and gas inside subsequently led to a series of explosions which badly damaged three of the reactors.
TEPCO has created a new system that removes radioactive substances from polluted water accumulating inside the plant and recycles the decontaminated water to cool the crippled reactors. But the water processing system has been plagued with problems and its operating rate has averaged just 69 percent since the system began operating in June, according to TEPCO.
As radioactive polluted water is created by injecting water into the damaged reactors, it is important to reduce the amount of water accumulating within the plant so that it does not overflow, Hosono said.
Hosono also said the government plans to start from September experimental projects on cleaning the radiation-contaminated areas outside the plant before implementing full-scale decontamination such as within a 20-kilometer radius of the plant designated as a no-entry zone.
During the press conference, TEPCO showed a video that delivered a message from Masao Yoshida, head of the Fukushima power plant, who apologized for causing great inconvenience amid the world's worst nuclear crisis since the 1986 Chernobyl disaster.
It was the first time that TEPCO made Yoshida's voice public since the nuclear crisis. In the video, available on TEPCO's website, he expressed gratitude for ''warm'' messages of support received from in and outside the country.
Yoshida drew media attention over his decision to continue injecting seawater into one of the troubled reactors in the early days of the crisis as an emergency step, despite an order to suspend the injection, at one point suspected to be coming from Prime Minister Naoto Kan.
The company issued a warning to him for falsely reporting the facts, although his decision was widely seen to be appropriate.
