JAPAN | Researchers invent new substance for decontaminating radioactive water

Posted on July 28, 2011

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JAPAN | MAINICHI | 28 july 2011

This satellite image provided by DigitalGlobe shows the damaged Fukushima Dai-ichi nuclear facility in Japan on Monday, March 14, 2011. Authorities are strugging to prevent the catastrophic release of radiation in the area devastated by a tsunami. (AP Photo/DigitalGlobe)

This satellite image provided by DigitalGlobe shows the damaged Fukushima Dai-ichi nuclear facility in Japan on Monday, March 14, 2011. Authorities are strugging to prevent the catastrophic release of radiation in the area devastated by a tsunami. (AP Photo/DigitalGlobe)

Researchers have developed a new material highly effective in cleaning the radioactive substances strontium and radioiodine out of contaminated water, the National Institute for Materials Science (NIMS) announced on July 27.

The discovery comes as those trying to cleanse vast quantities of radioactive contaminated water at the crisis-stricken Fukushima No.1 Nuclear Power Plant seek to boost the decontamination rate. NIMS and the Japan Atomic Energy Agency will cooperate to put the new material to practical use as soon as possible.

The material is silica with countless holes in it just 2 to 20 nanometers in diameter, each hole coated on their inner walls with a special compound. Depending on the type of material used, it binds to either radioiodine or strontium, taking the radioactive substances out of the water.

According to NIMS, one gram of the silica material can absorb 20 milligrams of radioiodine or 13 milligrams of strontium, or about 65 billion becquerels worth of strontium 90, produced in nuclear reactors.

The materials currently being used for decontamination also tend to filter out chlorine — similar to iodine — magnesium and calcium — similar to strontium. As sea water — used to cool the Fukushima reactors — has high concentrations of chlorine and magnesium, much of the cleansing material’s capacity is taken up filtering these elements, pushing down the decontamination rate. The new silica-based material, however, does not have this problem, and in the case of radioiodine, can even be reused.

“If factory-made, you can create tons of this material a day, and even at the laboratory level it costs just 60-70 yen per gram to make,” says project Chief Engineer Sherif El Safty. “It is extremely effective for decontamination.”

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