A troubled water purification system at the Fukushima No. 1 nuclear power plant has processed about 1,825 tons of radioactive water, Tokyo Electric Power Co. said on June 22.
A troubled water purification system at the Fukushima No. 1 nuclear power plant has processed about 1,825 tons of radioactive water, Tokyo Electric Power Co. said on June 22.
A series of malfunctions have plagued the system since it was installed at the start of June, but TEPCO said continued testing of the equipment had brought radiation levels in the processed water to about 1/100,000th of original levels.
The total volume of contaminated water on the plant's site has been reduced.
TEPCO officials said there would be another one to two days of testing before workers tried a full start. The system is being tested on highly radioactive water being stored at a central waste processing facility on the plant's grounds.
Between the night of June 17 and 10 a.m. on June 22, when the purifying system was stopped so a container could be replaced, the system processed a total of about 1,825 tons of contaminated water.
After passing through the system, the water was moved to a temporary tank, and a provisional measurement found that radioactivity had been reduced by about 100,000 times.
After the operation, the water level in the central waste processing facility was nearly 40 centimeters lower.
On June 21, contaminated water from the basement of the turbine building of the No. 3 reactor started to be moved to the central waste processing facility because of the extra capacity created. As a result, the water level of a trench shaft at the No. 3 reactor that is connected to the basement was held level at 12 centimeters from the surface. Before that, the water level was rising at a rate of about two centimeters a day.
There is still the possibility that contaminated water could overflow, even with the water purification system operating. The rainy season started in the Fukushima area on June 21. Heavy rain still threatens to increase the volume of contaminated water on the site to levels that might challenge TEPCO's ability to contain it.
TEPCO officials have already completed preparations to store about 1,000 tons of contaminated water in equipment at the central waste processing facility that is not currently in use. If levels rise dangerously, they are considering temporarily storing water in tanks for water contaminated with low levels of radiation.
The company has also decreased the volume of water being pumped into the three reactors at the Fukushima No. 1 plant for cooling purposes.
From 10 a.m. on June 22, the volume of water pumped into the No. 1 and No. 2 reactors was reduced by 1 ton.
After the volume of water pumped into the No. 3 reactor was reduced on June 21, temperatures increased by 3.4 degrees. The company is pumping about 10 tons per hour into that reactor and monitoring its state.
(This article was written by Hiroshi Ishizuka and Hidenori Tsuboya.)