An aerial view shows Tokyo Electric Power Co.'s (TEPCO) tsunami-crippled Fukushima Daiichi nuclear power plant in Fukushima Prefecture (Reuters / Kyodo)
Source: Russia Today
http://rt.com/news/fukushima-fuel-cleanup-operation-522/
Scientists at Japan’s Fukushima nuclear power plant are
preparing for their toughest clean-up operation yet – two and a half years
after three of the plant’s reactors suffered a meltdown in Japan’s worst-ever
nuclear power disaster.
The operation, to remove 400 tons of highly irradiated
spent fuel beneath the plant’s damaged Reactor No. 4, could set off a
catastrophe greater than any we have ever seen, independent experts warn. An
operation of this scale, says plant operator Tokyo Electric Power Company, has
never been attempted before, and is wrought with danger.
An uncontrolled leak of nuclear fuel could cause more
radiation than the March 2011 disaster or the 1986 Chernobyl catastrophe, say
consultants Mycle Schneider and Antony Froggatt. "Full release from the
Unit-4 spent fuel pool, without any containment or control, could cause by far
the most serious radiological disaster to date," the scientists say in
their World Nuclear Industry Status Report 2013.
The operation has been tried before – but only with the
aid of computers. This time it will be a painstaking manual process.
Here’s what needs to be done: more than 1,300 used fuel
rod assemblies, packing radiation 14,000 times the equivalent of the Hiroshima
nuclear bomb, need to carefully be removed from their cooling pool.
Arnie Gunderson, a veteran US nuclear engineer and
director of Fairewinds Energy Education, told Reuters that "they are
going to have difficulty in removing a significant number of the rods,"
especially given their close proximity to each other, which risks breakage and
the release of radiation.
Gundersen told Reuters of an incredibly dangerous “criticality”
that would result if a chain reaction takes place at any point, if the rods
break or even so much as collide with each other in the wrong way. The
resulting radiation is too great for the cooling pool to absorb – it simply has
not been designed to do so.
"The problem with a fuel pool
criticality is that you can't stop it. There are no control rods to control
it,” Gundsersen said. “The spent fuel pool cooling system
is designed only to remove decay heat, not heat from an ongoing nuclear reaction."
The base of the pool where the fuel assemblies are
situated is 18 meters above the ground. The pool itself is 10 by 12 meters, and
the rods are seven meters under the surface of the water. One problem with that
pool is it has been exposed to air in the 2011 catastrophe, when its roof was
blown off by the explosion.
The operation is urgent – because even a minor earthquake
could trigger an uncontrolled fuel leak.
A general view of the cover installation for the spent
fuel removed from the cooling pool is pictured at the No.4 reactor building at
Tokyo Electric Power Company's (TEPCO) tsunami-crippled Fukushima Daiichi
nuclear power plant in Fukushima prefecture (Reuters / Noboru
Hashimoto / l)
The removal process is due to begin in November, with
TEPCO predicting it will take approximately a year. Although TEPCO is confident
the operation will be a success, some experts are more skeptical. TEPCO is
currently failing to contain radioactive water seepage in another part of the
facility.
Two empty fuel rods were removed as part of a test
operation some time ago, but "to jump to the conclusion that it is
going to work just fine for the rest of them is quite a leap of logic,"
Reuters quoted Gundersen, of Fairewinds Energy Education as saying.
A giant steel frame currently towers over Unit 4, soon to
be tasked with the extraction of the fuel assemblies. Each fuel rod weighs at
around 300 kilograms and is 4.5 meters long. They also contain plutonium, one
of the most radioactive substances known to man. The radiation builds up during
the later stages of a core’s operation.
Toshio Kimura, a former TEPCO technician, told Reuters
that the operation would normally be assisted by computers, but that luxury is
gone. "Previously it was a computer-controlled process that memorized
the exact locations of the rods down to the millimeter and now they don't have
that. It has to be done manually so there is a high risk that they will drop
and break one of the fuel rods," he said.
He is also expecting many issues for TEPCO ahead, as the
process is estimated to take years. The scientists’ task is not made easier by
the fact that the building is also prone to corrosion from salt water.
Removing the fuel rods is just one part of the cleanup
operation, itself expected to take around four decades - according to the IAEA
- during which any number of other problems could arise.
The fuel rod scare comes as TEPCO is currently failing to
contain radioactive water seepage in another part of the facility – itself a
growing issue with no concrete solution, apart from building a special
underground wall. But with water quantity building up at an alarming rate, the
most likely version of events is that the radioactive water will simply have to
be released into the Pacific at some point. According to TEPCO, there are still
“no perfect solutions.”
"If you build a wall, of course the
water is going to accumulate there. And there is no other way for the water to
go but up or sideways and eventually lead to the ocean,"
Masashi Goto, a nuclear engineer who has worked at several TEPCO plants, told
Reuters. "So now, the question is how long do we have?"
This situation is not made easier by the fact that Japan
is a seismically active island. Earthquakes keep striking at random, and even a
small tremor could set in motion a catastrophic chain of events.
Costs soaring – no end in sight
Clean-up costs at the nuclear plant are projected to be
in the billions of dollars, as the facility’s operator has failed to meet its
targets, leading to increased public distrust and forcing the government to
step in.
In the two years since the March 2011 meltdown, the costs
of the cleanup project could be spiraling out of control financially. If the
clean-up is not carried out, it could cause incalculable problems for Japan’s
economy, particularly in agriculture.
The Institute for Industrial Sciences at the University
of Tokyo has recently estimated that the levels of radiation along the
country’s coastline are way above the government target.
"We have detected over 20 spots around
Fukushima Daiichi nuclear plant with levels of radiation five to 10 times
higher than the surrounding areas, with diameters ranging from tens to hundreds
of meters," the institute said.
TEPCO had been left to its own devices two years ago to
deal with the clean-up and the compensation payments to people in the
contaminated region. Now, with recent news of over 300 tons of contaminated
water being leaked into the Pacific for more than two years, the Japanese
government has decided to step in.
In the immediate aftermath of the disaster, the
government ordered Fukushima plant operator TEPCO to bear the entire costs of
the clean-up, but also told it to get back to profitability as soon as possible
through cost-cutting, so that it could pay off its debts. The clean-up will
weigh very heavily on Japan’s energy consumption, however, on top of the
already stringent energy austerity measures.
But TEPCO has insisted it will not be able to handle the
clean-up bill, which is now projected at more than $10 billion. The company has
already spent $3 billion and will require a major injection of $10 billion by
March 2014, it says.
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