Technology:
Desperate efforts
are being made to develop a technology for effective and efficient treatment of
polluted water in the Fukushima Daiichi Nuclear Power Plant. A research team of
Showa Denko and Hitoshi Mimura of Tohoku University developed a technology to
bake and harden residues of highly concentrated radioactive effluent, making it
possible to harden unstable sludge residues into a stable substance. Ferrocyanide
adsorbs radioactive substances like cesium effectively. Although it has 10
times stronger adsorption power than zeolite, it deposits muddy substance
called waste sludge. The purification equipment from Areva of France running in
Fukushima uses ferrocyanide. In Fukushima, the waste tank installed underground
has a capacity of 700 cubic meters, but it is already filled with 600 cubic
meters of waste sludge at present.
The above research
team mixed ferrocyanide residues with special zeolite at a ratio of 1 to 1-2
and baked them at 800-1,000 degrees centigrade, and subsequently pressed the
resultant product under high pressure. This technology can seal radioactive
substances completely in a solid as stable as dried cement. Should this
technology be applied, it will be possible to establish a treatment cycle that
scoops the surface soil in the highly contaminated area, mixes the surface soil
with water and ferrocyanide to eliminate radioactive substances, and solidifies
the residue. The new technology has rather high removal efficiency because it
can separate cesium and strontium from the soil almost entirely. Showa Denko
plans to sell it to Tokyo Electric Power Company with the help of Atomic Energy Society of Japan.
Toshiba presented
the manufacturing process of the Advanced Liquid Processing System (ALPS) that
can eliminate 62 kinds of radioactive substances including strontium. It can
process 500 tons of polluted water per day. Because about 200,000 tons of
polluted water still exists on the premises of the Fukushima Daiichi Nuclear
Power Plant, it will supposedly take about 400 days to treat all the polluted
water. Toshiba’s ALPS will be installed late August, and the trial run will
start in September. Using the special resins and activated charcoal, it can
decrease the concentration of radioactive substances to lower than the legal
level.
The adsorption
tower of Toshiba’s Advanced Liquid Processing System (ALPS) that can eliminate
62 kinds of radioactive substances in water.
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