20 Novembre 2013
November 19, 2013
Tokyo Electric Power Co. has finally moved into the decommissioning process at the Fukushima No. 1 nuclear plant, despite doubt over its ability to manage a highly dangerous effort that will take decades.
The start Monday of removing fuel from the cooling pool high up in the damaged reactor 4 building was one of the few bright pieces of news to come out recently from the plant, which has been plagued with frequent radioactive water leaks and other troubles over the past year.
But the work poses another challenge to the utility, with its success or failure expected to affect the following process of retrieving the fuel from the pools for reactors 1, 2 and 3, as well as the melted fuel inside the damaged cores.
“Spent fuel has potentially a very large risk. . . . I am personally more worried about (handling) it than the radioactive water problem,” Nuclear Regulation Authority Chairman Shunichi Tanaka said in late October.
Tepco President Naomi Hirose has vowed to take “all possible measures” to ensure safety, while another senior official said it is “very unlikely” that an incident will occur that could rekindle a sustained nuclear chain reaction, or criticality.
But some experts don’t feel reassured.
“It is quite certain that various kinds of troubles will occur, but I don’t think Tepco has prepared enough safety measures,” said Hideyuki Ban, co-director of the Citizens’ Nuclear Information Center, a group against nuclear power.
Among his concerns is an accident occurring after workers place fuel assemblies into transport casks inside the spent fuel pool on the shattered building’s fifth floor. As each of these 90-ton containers are filled, they will be lowered about 32 meters to the floor below so they can be trucked to another building.
Tepco claims its analyses show that the impact on the radiation level at the complex’s perimeter would be small even if a container were to be dropped and broken open.
Ban, however, said Tepco should look for options other than lowering the containers directly to the first floor, and that he is worried workers wouldn’t even be able to approach a container that has been damaged to the point where it is releasing high levels of radiation.
In addition to the decommissioning work, Tepco’s fight to manage the massive amount of radioactive water accumulating at the plant continues, with no quick remedy in sight.
Tepco has set up some 1,000 tanks to store the toxic water, which is increasing at a rate of about 400 tons a day as groundwater seeps into the basements of the reactor buildings and mixes with the water used to cool the three crippled units.
Its plans for water storage have turned out to be poor, with a series of leaks afflicting tanks that were quickly put together by bolting steel plates together amid the urgent need to expand capacity.
The structural weakness of these tanks is not the only flaw. A string of human errors that led some tanks to overflow and workers to be splashed with radioactive water alarmed regulators who saw it as a sign that Tepco’s ability to manage on-site activities was deteriorating and that morale was weakening.
With the utility apparently overwhelmed by the huge workload, Prime Minister Shinzo Abe’s administration has been stepping up its involvement in the cleanup activities, saying the matter “should not be left up to Tepco alone.”
The Abe team’s first move was to set aside ¥47 billion in public funds for projects to lessen the “technically challenging” radioactive water problem, including an unprecedented attempt to build a huge sunken ice wall to stop the groundwater from reaching the reactor buildings.
Based on a key proposal endorsed by the ruling parties earlier this month, the government is also considering shouldering some of the costs for decontaminating areas outside the plant, which could reach ¥5 trillion and is to be paid by Tepco.
The move would be a relief to the utility, which is in need of massive piles of cash to deal with compensation payments, the plant decommissioning and decontaminating off-site areas.
The utility has barely been kept afloat under a financial assistance scheme involving a government-backed fund created since the March 2011 start of the nuclear crisis. It also received a ¥1 trillion capital injection from the fund last year.
But in return for what could be seen as another bailout, pressure is growing on Tepco to revise its organizational structure so it can better manage the radioactive water and decommissioning operations.
“We can’t ask the public to shoulder the financial burden without securing public support. So we want Tepco to substantially reform itself,” said Tadamori Oshima, a lawmaker in the ruling Liberal Democratic Party who was involved in devising the proposal.
Sources have said Tepco is considering creating an in-house company to take charge of the decommissioning, but some experts speculate the utility’s true intention is to stave off possible calls for more drastic steps that could even threaten its existence.
While the government has been against forcing Tepco to declare bankruptcy because it would disrupt the compensation payments and cleanup missions, some ruling and opposition camp lawmakers continue to insist that stakeholders and creditor banks be held liable before using public funds to settle the crisis.
Tetsunari Iida, head of the Institute for Sustainable Energy Policies, said, “In my view, plans that do not involve legal liquidation are nothing more than a deception.”