A water purification system at Fukushima Daiichi was taken offline this week after it contaminated 21 tanks holding previously treated water.
Recent developments at the Tokyo Electric Power Co. plant blacked out and severely damaged three years ago include:
ALPS System Malfunctions
Engineers shut down the ALPS system that removes multiple radionuclides from water at Fukushima Tuesday after crews discovered it had not fully treated a portion of water flowing into storage tanks. Water from one of the system's three channels contained radionuclides at levels one-10th of their original concentrations, the Asahi Shimbun reported. The system is supposed to reduce those levels by a factor of 100,000, with TEPCO suspecting the problem stems from filter replacements earlier this month.
As a result, TEPCO estimated that up to 900 metric tons of partially treated water entered 21 tanks between March 14 and Tuesday. Associated piping and the tanks themselves must be cleaned before they can be reused, while 15,000 tons of water within them will need to be retreated. A plant manager quoted by the Asahi said he did not know whether the plant would attempt to clean them or how long that would take.
Once fixed, ALPS will be needed for treatment of another 340,000 tons of contaminated groundwater pumped from plant buildings and stored in tanks. International Atomic Energy Agency Director General Yukiya Amano reiterated this week that the sheer volume of water stored on site will necessitate the eventual release of treated water that contains small amounts of tritium.