Meltdown may have occurred also at Nos. 2, 3 reactors+

TOKYO, May 16 Kyodo -
An adviser to Prime Minister Naoto Kan said Monday that the operator of the Fukushima Daiichi nuclear power plant had failed to inject water into the Nos. 2 and 3 reactors for more than six hours after the March 11 massive earthquake and ensuing tsunami.
Goshi Hosono, tasked with handling the nuclear crisis, said at a press conference that Tokyo Electric Power Co. had not been able to cool down the reactors' cores due to loss of external power for a long time after the quake, acknowledging that fuel in the vessels might have largely melted ''in the worst-case scenario.''
But he added the utility, known as TEPCO, has been succeeding in preventing the reactor's fuel from overheating so far and reiterated the government will stick to the timetable set by the firm, which announced April 17 it aims to bring the crisis there under control in six to nine months.
His remarks came a day after TEPCO said a nuclear fuel meltdown at the No. 1 reactor is believed to have occurred around 16 hours after the devastating quake and tsunami crippled the plant's critical cooling systems.
TEPCO is slated to release on Tuesday an updated roadmap for bringing under control Japan's worst nuclear accident based on new information about the plant's condition.
Hosono has said that it has no choice but to abandon an initial plan to flood and cool the No. 1 reactor's containment vessel as holes have been created in the pressure vessel by the melted fuel.
The government will also unveil the same day its own version of a roadmap that will outline measures on how to deal comprehensively with the crisis amid growing discontent by lawmakers and the public over the government's handling of it.
TEPCO, meanwhile, said Monday it will start transferring highly radioactive water at the No. 3 reactor of the atomic power complex to a waste-disposing facility the following day to prevent it from leaking into the environment.
The move is believed to be essential to contain radiation leaks from the power station as well as to allow workers to get access to the damaged vessel, from which the contaminated water may be leaking to its adjacent turbine building and other places.
While such water previously found at the No. 2 reactor has been already stored in the facility, the utility has stepped up its efforts to set up equipment at the water-disposing facility to decontaminate the radioactive water so it can be reused to cool fuel in the vessels in the near future, company officials said.
Under a plan by TEPCO, a total of 4,000 tons of water is expected to be pumped out of the No. 3 reactor turbine building to the nuclear waste disposal facility by using hoses.
The utility has been injecting more water into the reactor than in the past to cool down its vessel as its temperature has been rising recently, pushing the level of water up there, the officials said.
The government's Nuclear and Industrial Safety Agency said it has already given the green light to TEPCO's plan.
The tainted water, the level of which has been rising by around 2 centimeters a day in the No. 3 reactor's turbine building, may be leaking into the sea, prodding the plant operator to remove it as soon as possible.
But TEPCO is also being forced to keep injecting sufficient quantities of water into the reactor as workers have been struggling to cool down its vessel stably.
The temperature inside the No. 3 reactor has been rising since the beginning of the month, topping 200 C on May 7, compared with around 90 C on May 1, TEPCO said.
While the temperature fell to 141.3 C on Monday morning, TEPCO remains vigilant as there is some skepticism about whether water has remained in the reactor, company officials said.