How effective is ALPS?

September 2, 2013

News Navigator: What is ALPS, and can it solve the radioactive water crisis?

http://mainichi.jp/english/english/perspectives/news/20130902p2a00m0na009000c.html

The Mainichi answers some common questions readers may have about the Advanced Liquid Processing System (ALPS) for decontaminating radioactive water at the Fukushima No. 1 nuclear power plant.

Question: There's a big problem now at the Fukushima No. 1 nuclear plant with highly radioactively contaminated water leaking from an above-ground storage tank, right? So how was plant operator Tokyo Electric Power Co. (TEPCO) planning to deal with the water in the tanks in the first place?

Answer: The space on the plant grounds is limited, meaning TEPCO can't keep building storage tanks forever. The utility is considering running the toxic water through the Advanced Liquid Processing System (ALPS) before dumping it in the Pacific Ocean. Test operations of the ALPS equipment began at the end of March this year.

Q: How does ALPS purify the water?

A: In the case of ALPS, the toxic water is passed through seven special materials that absorb target radioactive substances. It's basically the same concept as cleaning molecules behind nasty smells out of the air with charcoal filters. A total of 63 radioactive contaminants including plutonium and strontium have been found in the water at the Fukushima plant. TEPCO has said the ALPS system can get concentrations of 62 of those substances -- tritium is the lone exception -- below the government maximum for dumping waste water into the environment, and do it at a rate of 500 metric tons a day.

In June, however, corroded parts and other problems were found in the ALPS equipment, and the system is now off-line for inspections. As such, TEPCO has been unable to move forward with water decontamination, and the water has built up in the tanks on-site. TEPCO is planning to restart its ALPS test run by the end of September.

Q: What does "Advanced Liquid Processing System" really mean?

A: Exactly what it says; it processes contaminated liquids, water in this case, quickly. We hope that ALPS gets repaired quickly, so this cutting-edge technology can be put to practical use.

Q: And what about the tritium?

A: The beta radiation emitted by tritium is so weak it cannot penetrate human skin, meaning it also cannot reach inside the body. Even if tritium is taken internally, it does not accumulate and passes out of the body in urine. The amount of the element in the body is reduced by half by the tenth day after ingesting it. Compared to strontium and plutonium, which builds up in the lungs and bones and can cause tumors, the health effects of tritium are thought to be minor.

If the concentration of radioactive materials in the treated water still exceeds the government standard of 60 becquerels per cubic centimeter after it's been passed through ALPS, TEPCO is considering adding more, clean water to bring down the concentration. (Answers by Tomoki Okuyama, Science & Environment News Department)