Japan's embattled Tokyo Electric Power Co (TEPCO) offered the timeline more than five weeks after a giant quake and tsunami knocked out cooling systems at its six-reactor Fukushima Daiichi atomic power station.
Radiation has since leaked into the air, soil and sea from the coastal plant northeast of Tokyo, as emergency crews have doused overheating reactors and fuel rod pools to prevent full meltdowns of volatile fuel rods.
TEPCO's chairman Tsunehisa Katsumata said at a press conference that the utility aims to cool reactors and start reducing radiation from the explosion-charred facilities within three months.
Within six to nine months, TEPCO said in a statement, it expects to achieve "cold shutdowns" of all the six reactors, a stable condition in which temperatures drop and radiation leaks fall dramatically.
|The number of foreign visitors to Japan suffered its biggest ever decline in March, falling by 50 percent, as a massive earthquake and tsunami scared travellers away, the government said Thursday.|
"As the short-term targets, we have set two steps," said Katsumata. "Step one is to steadily reduce the amount of radiation.
"In step two, we aim to control the release of radioactive substances and greatly control the amount of radiation."
"There are various risks ahead," he added. "But we aim to complete step one in about three months and step two in another three to six months."
TEPCO also said that an initial focus would be on preventing new hydrogen explosions in reactors by injecting nitrogen, and on avoiding further releases of radioactive water into the environment.
Trade and industry minister Banri Kaieda said: "TEPCO has just unveiled the roadmap, which is an important step."
Kaieda said that the roadmap would help move the nuclear crisis from the emergency phase into a stabilisation phase.
"The government urges TEPCO to carry out the roadmap steadily or carry it out faster than planned," he said.
Kaieda also said that in six to nine months the government would review the evacuation area around the plant, having set a 20 kilometre (12 mile) exclusion zone and urged people to also leave from a wider 30 km radius.