Radiation Fatally High at
Japanese Nuclear Reactor
Japan Nuclear
Reactor
EMF Computer Protection
Magnetic Field Detector
Mar 28 2012
One of Japan’s crippled nuclear reactors still
has fatally high radiation levels and hardly any water to
cool it, according to an internal examination Tuesday that
renews doubts about the plant’s stability.
A tool equipped with a tiny video camera, a
thermometer and a water gauge was used to assess damage
inside the No 2 reactor’s containment chamber for the second
time since a tsunami swept into the Fukushima Dai-ichi plant
a year ago.
The data showed the damage from the disaster was
so severe the plant operator will have to develop special
equipment and technology to tolerate the harsh environment
and decommission the plant, a process expected to last
decades.
The other two reactors that had meltdowns could
be in worse shape. The No 2 reactor is the only one
officials have been able to closely examine so far.
The examination with an industrial endoscope
detected radiation levels up to 10 times the fatal dose
inside the chamber. Plant officials previously said more
than half of the melted fuel had breached the core and
dropped to the floor of the primary containment vessel, some
of it splashing against the wall or the floor.
Particles from melted fuel have probably sent
radiation levels up to a dangerously high 70 sieverts per
hour inside the container, said Junichi
Matsumoto, spokesman for Tokyo Electric Power Co.
The figure far exceeds the highest level
previously detected, 10 sieverts per hour, which was
detected around an exhaust duct shared by No 1 and 2 units
last year.
“It’s extremely high,” he said, adding that an
endoscope would last only 14 hours in those conditions. “We
have to develop equipment that can tolerate high radiation”
when locating and removing melted fuel during the
decommissioning.
The probe also found that the containment vessel
– a beaker-shaped container enclosing the core – had cooling
water up to only 60cm from the bottom, far below the 10
metres estimated when the government declared the plant
stable in December. The plant is continuing to pump water
into the reactor.
Video footage taken by the probe showed the
water inside was clear but contained dark yellow sediments,
believed to be fragments of rust, paint that had been peeled
off or dust.
A probe in January failed to find the water
surface and provided only images showing steam, unidentified
parts and rusty metal surfaces scarred by exposure to
radiation, heat and humidity. Finding the water level was
important to help locate damaged areas where radioactive
water is escaping.
Mr Matsumoto said the actual water level inside
the chamber was way off the estimate, which had used data
that turned out to be unreliable. But the results don’t
affect the plant’s “cold shutdown status” because the water
temperature was about 50C, indicating the melted fuel is
cooled.
Three Dai-ichi reactors had meltdowns, but the
No 2 reactor is the only one that has been examined because
radiation levels inside the reactor building are relatively
low and its container is designed with a convenient slot to
send in the endoscope.
The exact conditions of the other two reactors,
where hydrogen explosions damaged their buildings, are still
unknown. Simulations have indicated that more fuel inside No
1 has breached the core than the other two, but radiation at
No 3 remains the highest.
The high
radiation levels inside the No 2 reactor’s chamber mean it
is inaccessible to the workers, but parts of the reactor
building are accessible for a few minutes at a time – with
the workers wearing full protection.
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