TOKYO (AP) — The operator of Japan's tsunami-hit nuclear plant made final preparations Thursday to launch a crucial system to treat highly radioactive water that has hampered efforts to achieve the primary goal of cooling and stabilizing the damaged reactors.
More than 100,000 tons of radioactive water have pooled across the Fukushima Dai-ichi power plant, and it could overflow within a couple of weeks if action is not taken.
Operator Tokyo Electric Power Co. said workers Thursday made final tests on a treatment system ahead of full operation planned for Friday.
In test runs earlier this week using highly radioactive water kept temporarily in tanks, the machines successfully reduced cesium to about one-10,000th of the earlier levels, TEPCO said.
Three reactor cores had melted after the March 11 tsunami destroyed both power and backup generators, knocking out critical cooling systems.
Fresh water pumped into the reactors becomes contaminated and goes right through the damaged cores, seeping into reactor and turbine basements, utility pits and other parts of the plant.
Some radioactive water has leaked into the ocean, causing concerns about contamination of seafood.
The leakage stopped after the operator sealed cracks, built oil fences around the coastal plant and took other steps.
The water treatment system employs key components provided by Kurion Inc. of the United States and French nuclear fuel company Areva SA to reduce cesium and other radioactive materials.
The treatment system is expected to cost at least 53 billion yen ($660 million) through December.
TEPCO aims to process up to 1,200 tons of water per day and plans to eventually reuse the water as core coolant, spokesman Junichi Matsumoto said.
TEPCO is also taking steps to improve the environment inside and outside the plant.
Tents to cover reactor buildings to contain radiation are being built, and the operator is also setting up tents for workers to rest and avoid heat-induced problems during the summer.
Last week, the health ministry said 12 people came down with heatstroke, while eight workers may have exceeded the radiation exposure limit.
TEPCO and the government have said they aim to bring the reactors to "a stable and cold shutdown" by January.
But some experts say the plan is too optimistic because high radiation, contaminated water, debris and other obstacles have already caused delays.
