TEPCO says it is testing operation of the ALPS water treatment system at the plant. The system is a key part of decontamination measures and is said to be capable of removing almost all radioactive substances from wastewater.
But TEPCO officials say they found performance had sharply deteriorated in one of 3 lines in the ALPS system when operation was halted to clean filters.
An analysis on Monday of water after treatment showed amounts of beta ray-emitting radioactive substances were reduced to only about one-tenth the amount in the water before the treatment. The system normally reduces radioactive contaminants to about one-millionth the prior level.
TEPCO halted all 3 lines in the treatment system early on Tuesday afternoon to determine the cause of the deterioration.
It plans to resume full operation of the system after April.
The ALPS system has had a series of problems, raising questions about its stability.
And from the photo analysis of Ray Masalas