Speaking on a NHK
Sunday news program, Kyoto University assistant professor Hiroaki
Koide commented that the Fukushima Daiichi nuclear power plant has
become like a swamp filled with radioactive material.
Koide was referring
to the fact that, ever since the meltdowns triggered by a March 2011
earthquake and tsunami, the Tokyo Electric Power Company (TEPCO) has
been relying on a constant influx of water to keep the plant cool.
The process of flowing past the reactors renders the water
radioactive, however, so radioactive water has been accumulating at
the plant for years. In that time, multiple leaks have caused the
contaminated water to spill into the surrounding area, creating a
sort of radioactive swamp.
Koide said that he
has been calling on TEPCO for a year to shift from using water for
cooling to using air. The company insists that that is impossible, as
it does not know the exact locations of the melted down fuel rods
inside the plant.
Water has been at
the heart of TEPCO's problems keeping the failed plant shut down
since day one. During the initial meltdown, the company funneled
large amounts of seawater past the melting down reactors as an
emergency cooling mechanism. This corroded sensitive equipment and
many of the valves and pipes used for cooling the plant. Leaks have
been springing up ever since.
In addition to the
radioactive cooling water, groundwater has also started seeping into
the basements of the reactors, where it, too, becomes radioactive.
TEPCO has been pumping the contaminated water out of these basements
and storing it in giant tanks, or simply ejecting it into the Pacific
Ocean. Although TEPCO claims that the radiation levels in the water
are low enough that dumping it in the ocean will not cause any harm,
the company's own tests have shown radiation levels above the safe
exposure threshold set by TEPCO.
The vast quantities
of radioactive water accumulating on-site are a significant threat to
the health of workers attempting to clean up the plant. They are also
interfering with the cleanup operation itself. For example, a series
of underground trenches connecting the turbine buildings for reactors
2 and 3 have been filling up with contaminated water leaking into
them from nearby containment vessels. Eventually, these trenches will
fill up, and the water will spill into the surrounding environment.
The Nuclear Regulation Authority called this possibility the "most
serious source of concern" and has ordered TEPCO to remove all
the water from these trenches.
But 11,000 tons of
radioactive water are not easy to move, and the amount of water in
the trenches is growing every day. To address both of these problems,
TEPCO has attempted to construct an "ice wall": a network
of pipes surrounding the trenches, through which a subzero coolant
will be piped, in order to freeze the trenches solid.
Coolant began
flowing on April 28 and was supposed to freeze the trenches within a
month. As of Saturday, August 2, no ice walls had yet formed only
a slushy goo. TEPCO claims that the procedure is failing because too
much water is flowing around the connecting joints of the pipes.
The failure to
freeze the trenches is widely viewed as an ominous sign for TEPCO's
much more ambitious plans for a 1.5 km (0.93 mile) -long, 30 m (100
ft) -deep ice wall completely encircling the number 1 and 4 reactors,
to prevent any more groundwater from flowing down into the buildings'
basements.
The larger ice wall
is intended to be operational in March, but work is proceeding
slowly. Due to their heavy radiation-proof clothing, workers can only
be out between 5 pm and 11 pm without risking heat stroke.
Kyodo
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