TOKYO (Kyodo) -- Around 1.1 tons of radioactive water overflowed Wednesday from a container during cleansing of a water treatment system at the crippled Fukushima Daiichi nuclear power complex, plant operator Tokyo Electric Power Co. said.
The water did not leak outside due to a barrier and remained inside the building housing the so-called Advanced Liquid Processing System, a facility that has been in trial operation since March last year.
The incident occurred as workers were flushing material that has absorbed radioactive substances into a waste container. But they noticed the container was overflowing at about 12:20 p.m.
The water contained around 3.8 million becquerels per liter of beta radiation emitting radioactive materials such as strontium-90. Workers were not contaminated with the radioactive materials, according to TEPCO.
TEPCO had to clean ALPS because it found one of the three lines was not removing radioactive substances to the level required.
The utility has developed the system to drastically reduce the radiation level of highly contaminated water that is accumulating at the plant as a result of continuing water injection into the three cripple reactors. But the system has been plagued with trouble.