The operator of Japan's crippled Fukushima Daiichi nuclear plant has said it expects to bring the crisis under control by the end of the year.

日本福岛核电站运营商称，此次危机将于今年年底才能处于掌控之中。

Tokyo Electric Power Co (Tepco) aims to reduce radiation leaks in three months and to cool the reactors¹ within nine months.

The utility said it also plans to cover the reactor² building, which was hit by a huge quake and tsunami³ on 11 March.

Nearly 14,000 people died and another 14,000 are still unaccounted for（下落不明的） .

Tepco unveiled its roadmap as Hillary Clinton briefly⁴ visited Tokyo to pledge America's "steadfast⁵ support" for Japan's reconstruction⁶.

'Cold shutdown'

Radiation levels in the sea near reactor 2 rose to 6,500 times the legal limit on Friday, up from 1,100 times a day earlier, Tepco has said, raising fears of fresh radiation leaks.

Tsunehisa Katsumata, the chairman of Tepco, Asia's largest utility, told a news conference in Tokyo on Sunday they would need up to nine months to bring the power plant to ''cold shutdown''.

He said the plan would allow the tens of thousands of families evacuated⁷ from the area around the facility to return home as soon as possible.

"We sincerely apologise for causing troubles," Mr Katsumata said. "We are doing our utmost to prevent the crisis from further worsening."

Tepco said after cold shutdown it would focus on encasing the reactor buildings, cleaning up contaminated soil and removing nuclear fuel.

Japan's government had ordered Tepco to come up with a timetable to end the crisis, now rated on a par⁸ with the world's worst nuclear accident, the 1986 Chernobyl disaster.

But the BBC's Roland Buerk in Tokyo says it is still not certain that the nine-month deadline can be achieved.

He says the immediate⁹ priority for Tepco is to stop radioactive water leaking into the Pacific Ocean.

The utility said it was sending remote-controlled robots into one of the reactors on Sunday to gauge¹⁰ radiation and temperature levels.

UK defence contractor¹¹ QinetiQ said it had provided the machines, which are controlled using a standard games console.

The robots can carry out tasks such as rubble¹² clearance¹³, demolition¹⁴（拆除，破坏） and radiation testing.

Japan is a world leader in such technology, but its robots are not adapted for dirty work such as meltdowns at nuclear plants, experts say.