TEPCO has announced that the first of the three units of a significantly-enhanced ALPS water treatment system, which is designed to remove most remaining radioactive contaminants from water at the Fukushima Daiichi Nuclear Power Station, has been installed and began hot testing in early September.
The other two units are expected to be started in September and October. When all three units are operating, treatment capacity will be doubled from the current 750 tons a day to 1500 tons a day. This system incorporates 10 adsorption towers.
The existing ALPS system, which consists of Japanese and international technologies, was first installed at Fukushima Daiichi in October 2012 and has since treated approximately 130,000 tons of water to remove 62 nuclides, excepting two. Most caesium had been removed via the initial SARRY or Kurion systems; tritium is not removed.
Installation and testing of a unit of the new improved ALPS system, which has the same design as the existing system but has more rugged, higher adsorption and monitoring capabilities, marks an increase of capacity of the ALPS complex by 250 tons a day. The improvements built into the newer ALPS system reflect the lessons learned from the earlier ALPS design. They include new rubber linings to prevent erosion, improved monitoring of water flow, improved leak detection, enhanced backup equipment and enhanced physical barriers to contain any leaks. The new system also has more adsorption towers.
Meanwhile, a separate, even more advanced ALPS system, treatment capacity 500 tons/day, has also been installed and is due to start testing in October. This system, developed in a project subsidized by the Japanese government, consists of 20 towers that treat contaminated water with much lower waste volumes: as little as 5% of the current system’s levels.
TEPCO is also preparing to treat water with strontium removal facilities manufactured by such companies as Toshiba, Hitachi and Kurion.
Photo: Improved ALPS building adsorption tower (in August 2014)
