Japan's embattled Tokyo Electric Power Co (TEPCO) offered the timeline in a press conference more than five weeks after a giant quake and tsunami knocked out cooling systems at its six-reactor Fukushima nuclear 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 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.
"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 hydrogen explosions in the reactors one, two and three by injecting nitrogen, and on avoiding further releases of radioactive water into the environment.