How can we get rid of radioactivity that still exists in the Pacific Ocean, years after the Fukushima accident?
A steady increase in volume of the stored water (about 400 m3/d net) is due to groundwater finding its way into parts of the plant and needing removal and treatment. In October 2012 Tepco was reported to be struggling to store over 200,000 m3 of contaminated water while anticipating the start-up of a new Toshiba water treatment plant, in November, which was to allow discharge of clean water to the sea.
Early in 2013 Tepco started to test and commission this Advanced Liquid Processing System. Each of three trains is capable of processing 250 m3/day to remove 62 remaining radioisotopes. Initially Tepco planned to run two simultaneously while holding the third in reserve, but then it planned three-stream operation from April 2014 with a view to treating all the water by early 2015. The ALPS is a chemical system which will remove radionuclides to below legal limits for release.