,
the Fukushima Daiichi power plant “resembled a field hospital”,
according to the man who is now in charge of the most daunting task the
nuclear industry has ever faced:
removing hundreds of tons of melted
fuel from the plant’s stricken reactors.
“Now it really does feel like the situation is settling down and we
can look ahead,” said Naohiro Masuda, head of decommissioning at the
plant’s operator, Tokyo Electric Power Company (Tepco).
and caused a triple meltdown at Fukushima, the plant has been
transformed from the scene of a major disaster into a sprawling building
site.
Masuda can point to lower radiation levels in and around the plant, better conditions for its 1,200 Tepco staff and 6,000 other
– including the recent provision of hot meals and a rest area – and
progress in containing huge quantities of radioactive groundwater.
In late 2014, the utility overcame arguably the most dangerous challenge since the meltdown, with the
from a storage pool inside a damaged reactor building.
But work on removing the melted fuel – something no nuclear operator has ever attempted – has barely begun.
– is that fuel in three reactors melted down after the tsunami knocked out the plant’s cooling system on 11 March 2011.
Of greatest concern, though, is reactor 1, where the fuel may have
burned through the pressure vessel, fallen to the bottom of the
containment vessel and into the concrete pedestal below – perhaps even
outside it – according to a report by the
International Research Institute for Nuclear Decommissioning . Reactors 2 and 3 are thought to have suffered partial meltdowns.
Masuda and Tepco engineers who spoke to the Guardian conceded that
they still didn’t know where the fuel is located. “To be honest, we
don’t know exactly where the fuel is and have to carry out more
studies,” Masuda said at a recent briefing. “But we do know that the
fuel is in a solid state of cold shutdown.
“No one has ever done what we’re doing, but 30 to 40 years is a
target that we can work towards. There are so many people involved that
it would be wrong to alter that deadline on a whim. We’ve established a
goal and need to show ingenuity to reach it, not take the easy way out.”
The technology needed to send robots deep into the reactors’ bowels –
where radiation levels are dangerously high – has yet to be developed.
Two robots specially tailored to negotiate debris inside damaged tunnels
and pipes
stalled last year when they closed in on the reactors’ highly radioactive innards.
Yet Tepco is persisting with the government’s roadmap for the
Fukushima
cleanup, which envisions fuel removal to begin in 2021 and end between
30 and 40 years later, at an estimated cost of almost $20bn (£14bn).
But Shaun Burnie, senior nuclear specialist at Greenpeace Germany,
said the decommissioning schedule was an attempt to convince the public
that
Japan was recovering from a major nuclear disaster.
“The idea that fuel debris removal will begin in 2021 is not
realistic – it’s just not going to happen,” he said. “The roadmap is
based on political considerations, not technical ones.
“This applies to the government’s and industry’s approach to the
whole Fukushima crisis – to give the impression that things are retuning
to normal and to weaken public opposition to the
restart of nuclear reactors .
“No one really knows how long it will take, but it will be decades and decades and decades.”
As the deadline for the start of fuel removal edges closer, even
industry regulators are beginning to question the methods set out in the
current decommissioning plan.
Last month, Toyoshi Fuketa, a nuclear regulatory authority
commissioner, suggested removing all of the melted fuel could take much
longer than four decades. “I wonder if it is desirable for work to
extract fuel debris to still be going on 70 or 80 years from now,”
Fuketa told reporters. “There are a number of other options, including
removing as much fuel as possible and solidifying the rest.”
Fukushima Daiichi’s stability is wholly dependent on water constantly
being directed into the reactor basements to prevent the fuel inside
from heating up. While the method has proved effective, it has led to a
buildup of enormous quantities of contaminated water – a mixture of the
coolant and groundwater that becomes radioactive when it flows from
hills behind the plant into the reactor buildings.
The contaminated water is then pumped out and stored in tanks that
cover large areas of the Fukushima Daiichi site. Tepco is able to remove
62 radionuclides from contaminated water – but not
tritium – and has so far been unable to get permission from local fishermen to release the treated water into the Pacific Ocean.
While pumping out groundwater upstream and redirecting it into the
sea has reduced the amount flowing into the reactor basements from 400
tonnes to 150 tonnes a day, the technology that was supposed to deliver a
coup de grace to Tepco’s perennial water problem has encountered
problems.
The utility’s plans to activate a 32bn yen (£198m) impermeable
frozen wall ,
which was completed earlier this year, have been frustrated by delays
and questions about its effectiveness. It hopes to start filling the
underground wall’s maze of pipes with water later this year.
The site is nearing its current water storage capacity of 850,000
tonnes, and there are plans to add to the existing 1,000 tanks, bringing
the amount of contaminated water at the plant close to one million
tonnes.
Tepco expects to have collected and treated all contaminated water
pooled around the reactors by 2020, and will need to continue processing
only coolant water for the reactors, according to Sadanobu Kanno, a
general manager in the firm’s nuclear power and plant siting division.
The slow progress at Fukushima is mirrored in the painstaking effort
to make nearby towns and villages, abandoned five years ago, fit for
human habitation.
Thousands of large black plastic bags containing radioactive soil and
debris removed from towns and villages near the Fukushima nuclear power
plant. Photograph: Franck Robichon/EPA
The disaster forced 160,000 people to flee their homes, 100,000 of whom are still
displaced .
About 10,000 children whose families fled after the nuclear disaster
have yet to return to Fukushima prefecture, amid parental concern over
the possible
health effects of long-term exposure to relatively low doses of radiation.
Their former hometowns have since been turned into temporary dumping
grounds for more than 10m black bags containing soil and other low level
radioactive waste cleared from areas around homes, schools and other
public buildings.
Here, too, progress is slow, with local authorities reporting that more than 40 communities have yet to be
decontaminated .
The unprecedented cleanup, involving 26,000 workers, aims to reduce
outdoor radiation exposure to one millisievert a year – a target Japan’s
environment minister recently criticised as
unrealistically low .
But in a blow to the government’s push to
lift more evacuation orders in Fukushima
communities over the next 12 months, a poll published on the eve of the
fifth anniversary of the disaster showed that two out of three nuclear
evacuees had given up hope of ever returning to their homes.
“It is wrong for the central government to say return home and to
lift evacuation orders, even though its own declaration of an emergency
situation for the nuclear accident is still in place,” said
Miyako Kumamoto, a 73-year-old evacuee , at a rally in Tokyo last week.
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