TOKYO, May 17 (Reuters) - The following is what Tokyo Electric Power (Tepco), the operator of the nuclear power plant crippled by a devastating earthquake and tsunami in March, aims to achieve during a self-imposed timeline as it tries to bring the plant under control.
WHAT IT WANTS TO ACHIEVE
Tepco said a month ago it wants to stabilise the damaged reactors at the Fukushima Daiichi nuclear plant, 240 km (150 miles) north of Tokyo, by mid-July and bring them to a "cold shutdown" by January. It said on Tuesday that it will stick to its timeline although it will revise some of its methods.
Tepco is also aiming to prevent the spread of radioactive substances and treat or store the tens of thousands of tonnes of radioactive water that have accumulated at the plant.
COOLING THE REACTORS
Of the six reactors at the Daiichi plant, two are considered relatively stable while four remain volatile.
Tepco's goal is to bring reactors No.1, No.2 and No.3, which were in operation when the disaster struck, to a cold shutdown.
A cold shutdown describes a state in which the water containing the fuel is below 100 degrees Celsius and is considered stable.
Tepco tried to submerge the nuclear fuel in reactor No.1 with water, in a method known as water entombment. But that plan was derailed when Tepco discovered the fuel had overheated and melted early in the crisis, puncturing the vessel containing the fuel.
Tepco said on Tuesday that it will now try to bring the reactor to a cold shutdown by treating and circulating the water that has already accumulated in the concrete reactor and turbine buildings while attempting to seal the leaks.
"Our aim is still to cool the reactors, we are simply changing methods," said Tepco Vice President Sakae Muto told reporters.
PREVENTING THE SPREAD OF RADIATION
Tepco said it will continue to spray the compound with resins to prevent contaminated dust from floating into the atmosphere. It is also working to cover the No.1, No.2 and No.3 reactors with giant tents.
It is also considering driving wedges around the reactor buildings to prevent pools of radioactive water from seeping out and contaminating groundwater.
TREATMENT, STORAGE OF CONTAMINATED WATER
Tepco estimates that 87,500 tonnes of radioactive water has pooled up at Daiichi, with another 500 tonnes per day being added as it hoses down the reactors.
It is running short of places at Daiichi to store the water and is building extra tanks to make more room. Tepco will also tow in a giant barge for storage.
The utility said on Tuesday that it hopes to eventually treat the contaminated water on site. It added that it aims to treat all the contaminated water at Daiichi by the year-end by building a plant that can treat 1,200 tonnes of water a day.
GOVERNMENT STEPS TO DEAL WITH VICTIMS
Separately, the government, under fire for its handling of the crisis, presented its own timetable on how to deal with the victims of the nuclear disaster. It said 42,000 people had been evacuated from the vicinity of the plant as of early May.
The government will build 15,200 temporary housing units by mid-August, with more to be constructed if needed.
The plan also included steps such as radiation checks for the evacuees, monitoring of radiation levels in the air, soil and sea, and measures to help create jobs.
The government plans to improve conditions for the workers at Daiichi, including better conditions for eating, bathing and sleeping. The government has ordered Tokyo Electric to make sure workers receive thorough radiation checks and health check-ups. In the long-term, it will create a data base to track radiation levels for all workers and monitor their health even after they have stopped working at the plant. (Reporting by Shinichi Saoshiro and Kiyoshi Takenaka; Editing by Chris Gallagher)
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