"We
are not optimistic but I think we can inject water once we can reopen
the valve and lower air pressure," the plant's operator stated.
Earlier, a hydrogen
blast at Japan's earthquake-stricken nuclear plant did not damage its
primary containment vessel, the UN nuclear agency said.
The
International Atomic Energy Agency (IAEA) said it was told by Japanese
nuclear authorities the control room of the unit No. 3 reactor at the
Fukushima Daiichi nuclear plant remained operational, following Friday's
massive earthquake and tsunami.
"The
reactor building exploded but the primary containment vessel was not
damaged. The control room of unit 3 remains operational," the IAEA said
in a statement.
"All personnel at the site are accounted for. Six people have been injured," it said in a statement on its website.
The core container of the No. 3 reactor was intact after the explosion,
the government said, but it warned those still in the 20-kilometer
(13-mile) evacuation zone to stay indoors.
A Japanese official said before the blast 22 people had been confirmed
to have suffered radiation contamination and up to 190 may have been
exposed. Workers in protective clothing used hand-held scanners to check
people arriving at evacuation centers.
US warships and planes helping with relief efforts moved away from the
coast temporarily because of low-level radiation. The US Seventh Fleet
described the move as precautionary.
US government officials told the NY Times
that sailors and other military personnel on-board were exposed to a
month's worth of radiation in an hour's time. They added that US
helicopters flying humanitarian missions some 60 miles north of damaged
Japanese reactors were coated with particulate radiation. The aircraft
were washed off.
The government had warned of a possible explosion at the No. 3 reactor
because of the buildup of hydrogen in the building housing the reactor.
TV images showed smoke rising from the Fukushima facility, 240 km (150
miles) north of Tokyo.

An explosion blew the roof off the No. 1 reactor building on Saturday.
Officials confirmed on Sunday that three nuclear reactors north of Tokyo
were at risk of overheating, raising fears of an uncontrolled radiation
leak.
Engineers worked desperately to cool the fuel rods. If they fail, the
containers that house the core could melt, or even explode, releasing
radioactive material into the atmosphere.
Humanitarian crisis growingMeanwhile,
Japan battled through the weekend to prevent a nuclear catastrophe and
to care for the millions without power or water in its worst crisis
since World War Two.
Kyodo news agency said 2,000 bodies had been
found on Monday on the shores of Miyagi prefecture, which took the
brunt of the tsunami.
A TV station also reported a new tsunami on Monday but the weather agency said it had not detected unusual wave movement.
A
badly wounded nation has seen whole villages and towns wiped off the
map by a wall of water, leaving in its wake an international
humanitarian effort of epic proportions.
Japanese Prime Minister
Naoto Kan said the situation at the crippled Fukushima nuclear plant
remained worrisome and that the authorities were doing their utmost to
stop damage from spreading.
"The earthquake, tsunami and the
nuclear incident have been the biggest crisis Japan has encountered in
the 65 years since the end of World War Two," a grim-faced Kan had told a
news conference on Sunday.
"We're under scrutiny on whether we, the Japanese people, can overcome this crisis."
Death toll 'above 10,000'Broadcaster
NHK, quoting a police official, said more than 10,000 people may have
been killed as the wall of water triggered by Friday's 8.9-magnitude
quake surged across the coastline, reducing whole towns to rubble. It
was the biggest to have hit the quake-prone country since it started
keeping records 140 years ago.
"I would like to believe that
there still are survivors," said Masaru Kudo, a soldier dispatched to
Rikuzentakata, a nearly flattened town of 24,500 people in far-northern
Iwate prefecture.
Kyodo said 80,000 people had been evacuated
from a 20-km (12-mile) radius around the stricken nuclear plant, joining
more than 450,000 other evacuees from quake and tsunami-hit areas in
the northeast of the main island Honshu.
Almost 2 million
households were without power in the freezing north, the government
said. There were about 1.4 million without running water.
"I am looking for my parents and my older brother," Yuko Abe, 54, said in tears at an emergency center in Rikuzentakata.
"Seeing
the way the area is, I thought that perhaps they did not make it. I
also cannot tell my siblings that live away that I am safe, as mobile
phones and telephones are not working."