ID :
180576
Sat, 05/07/2011 - 18:08
Auther :
Shortlink :
https://oananews.org//node/180576
The shortlink copeid
Radiation levels drop inside troubled No. 1 reactor building
TOKYO, May 7 Kyodo - Radiation levels have dropped inside the building housing the No. 1 reactor at the crippled Fukushima Daiichi nuclear power plant, the plant's operator said Saturday, a development that would pave the way for workers to reenter the site to stabilize the reactor.
The operator, Tokyo Electric Power Co., known as TEPCO, attributed the drop to a ventilator installed in the building on Thursday to filter out radioactive substances inside.
TEPCO has been struggling to bring the six-reactor complex in Fukushima Prefecture under control ever since the March 11 tsunami triggered by a major earthquake knocked out the plant's vital cooling functions and severely crippled the Nos. 1 to 3 reactors with nuclear fuel left inside their cores.
Radiation levels rose Friday, but TEPCO said it occurred because the ventilator stirred the air inside the building, leading a temporary spike.
The lower levels would reduce the risk of plant workers being exposed to elevated levels of radiation when they build a new cooling system for the reactor inside the building.
TEPCO is planning to open doors that connect the building and an adjacent turbine building soon, possibly on Sunday afternoon, to begin work on building the cooling system. But leaving them open for a long period of time would risk releasing radioactive substances into the air through a damaged part of the reactor building, the utility said.
The company will therefore assess the possible environmental impact of the move and seek an appraisal from the government before opening the doors.
Earlier Saturday, TEPCO officials said around 800 workers have spent more than a month dealing with the nuclear crisis at the power plant, but they have only recently started to undergo medical checkups.
It took nearly two months after the crisis erupted following the March 11 quake and tsunami to commence regular health checks as the health ministry had initially only required them to be performed after the crisis ends, assuming it would not be prolonged, according to the officials.
Of the workers, 30 have been exposed to over 100 millisieverts of cumulative radiation. However, with the exception of three workers exposed on March 25 to high-level radiation and those who have already ceased working at the plant, the workers only began to undergo their first examinations this month, the officials said.
The checks came after the Health, Labor and Welfare Ministry instructed employers on April 25 to immediately examine the health of workers who have been dealing with the crisis for more than a month or who have been exposed to more than 100 millisieverts of radiation.
Around 500 employees of the utility and about 300 workers from its affiliates and other companies have worked at the troubled plant for more than a month, with several hundred workers per day engaging in on-site efforts to contain Japan's worst ever nuclear accident, according to TEPCO.
However, they have only just begun to meet doctors commissioned by their employers as part of what will be monthly checkups as it took time to determine the number of such workers, the officials said.
Initially, the ministry told the employers on March 16, a day after it raised the legal limit for radiation exposure in an emergency to 250 millisieverts from 100 millisieverts to deal with the current crisis, to check the health of workers exposed to over 100 millisieverts after they finish their work.
Although six workers had been exposed to more than 100 millisieverts of radiation as of March 19, no checkups were performed amid the continuing crisis, prompting the ministry to issue its updated directive more than a month later, the officials said.
The number reached 30 on April 23, including the three who on March 25 stepped into a highly radioactive pool of water while laying cable in the basement of the No. 3 reactor's turbine building as part of efforts to restore the plant's cooling functions.
The operator, Tokyo Electric Power Co., known as TEPCO, attributed the drop to a ventilator installed in the building on Thursday to filter out radioactive substances inside.
TEPCO has been struggling to bring the six-reactor complex in Fukushima Prefecture under control ever since the March 11 tsunami triggered by a major earthquake knocked out the plant's vital cooling functions and severely crippled the Nos. 1 to 3 reactors with nuclear fuel left inside their cores.
Radiation levels rose Friday, but TEPCO said it occurred because the ventilator stirred the air inside the building, leading a temporary spike.
The lower levels would reduce the risk of plant workers being exposed to elevated levels of radiation when they build a new cooling system for the reactor inside the building.
TEPCO is planning to open doors that connect the building and an adjacent turbine building soon, possibly on Sunday afternoon, to begin work on building the cooling system. But leaving them open for a long period of time would risk releasing radioactive substances into the air through a damaged part of the reactor building, the utility said.
The company will therefore assess the possible environmental impact of the move and seek an appraisal from the government before opening the doors.
Earlier Saturday, TEPCO officials said around 800 workers have spent more than a month dealing with the nuclear crisis at the power plant, but they have only recently started to undergo medical checkups.
It took nearly two months after the crisis erupted following the March 11 quake and tsunami to commence regular health checks as the health ministry had initially only required them to be performed after the crisis ends, assuming it would not be prolonged, according to the officials.
Of the workers, 30 have been exposed to over 100 millisieverts of cumulative radiation. However, with the exception of three workers exposed on March 25 to high-level radiation and those who have already ceased working at the plant, the workers only began to undergo their first examinations this month, the officials said.
The checks came after the Health, Labor and Welfare Ministry instructed employers on April 25 to immediately examine the health of workers who have been dealing with the crisis for more than a month or who have been exposed to more than 100 millisieverts of radiation.
Around 500 employees of the utility and about 300 workers from its affiliates and other companies have worked at the troubled plant for more than a month, with several hundred workers per day engaging in on-site efforts to contain Japan's worst ever nuclear accident, according to TEPCO.
However, they have only just begun to meet doctors commissioned by their employers as part of what will be monthly checkups as it took time to determine the number of such workers, the officials said.
Initially, the ministry told the employers on March 16, a day after it raised the legal limit for radiation exposure in an emergency to 250 millisieverts from 100 millisieverts to deal with the current crisis, to check the health of workers exposed to over 100 millisieverts after they finish their work.
Although six workers had been exposed to more than 100 millisieverts of radiation as of March 19, no checkups were performed amid the continuing crisis, prompting the ministry to issue its updated directive more than a month later, the officials said.
The number reached 30 on April 23, including the three who on March 25 stepped into a highly radioactive pool of water while laying cable in the basement of the No. 3 reactor's turbine building as part of efforts to restore the plant's cooling functions.
