NISA says Fukushima-1 No. 3 reactor may be damaged
Tokyo (Platts)--25Mar2011/752 am EDT/1152 GMT
Japan's Nuclear and Industrial Safety Agency said Friday that the
government now does not rule out the possibility that Tokyo Electric Power
Company's Fukushima-1 No 3 reactor container may be damaged, after it
detected higher radiation levels than normal inside the reactor building.
A NISA official said the government was looking at whether the No. 3
reactor container or pipelines inside the reactor building have been damaged
after three workers were exposed to high radiation late Thursday.
NISA has measured the radiation inside the No. 3 building at 400
millisieverts/hour, the official said. Radiation detected in water inside the
reactor building where the workers were exposed was measured at 10,000 times
the usual level, he added.
"When we look at the composition of the water, the source of the water
seems to be the reactor core," said the official. However, he added that "core
reactor damage such as cracks has not been conclusively discovered."
He said it was also possible that the contaminated water could have come
from the spent fuel storage pool.
On Thursday, at least two workers suffered radiation exposure while
working in the basement of the building to connect power cables to restore the
cooling system. A third may have been exposed and all three have been taken to
the National Institute of Radiological Sciences for testing and treatment, he
The workers were exposed to about 170 millisieverts/hour of radiation, a
Tepco official told public broadcaster NHK Thursday.
Meanwhile, although work inside of the No. 3 reactor has been suspended,
spraying and water injection operations have been conducted again at reactors
No. 2, 3 and 4 using seawater.
Some preparations are underway, however, to start switching to freshwater
to limit the corrosive effect of seawater on reactor equipment, and the US
military is providing support.
"A US military ship is presently on its way to the plant full of [fresh]
water that we will use as a backup," said Defense Minister Toshimi Kitazawa.
Also, the national government has started warning local governments in
the areas surrounding the Fukushima-1 plant to prepare for a possible
expansion of the evacuation zone.
An evacuation zone of a 20-km radius has been established around the
stricken nuclear plant, while resident living between 20 km and 30 km of the
plant have been advised to remain indoors.
Many people have already evacuated from the 20-30-km zone already, said
Chief Cabinet Secretary Yukio Edano because "life in the community has become
He said it has become increasing difficult to deliver food and other
goods to the area.
He added that local governments should start preparing in case radiation
levels increase and evacuation from the larger area becomes necessary.
"There is no immediate likelihood that the plant will stop emitting
radiation," he said.
Separately, Tepco told news agency AFP that it may take a month to
achieve cold shutdown of the Fukushima-1 plant.
AFP also said NISA was considering raising the nuclear event level higher
than the current 5 out of 7, which is the same level as the 1979 accident at
Three Mile Island, Pennsylvania, in the US.
Japan's nuclear power regulator indicated Friday, said the AFP, that it
may raise its assessment of the crisis at the nuclear plant to level six, or
An NISA official was quoted as saying: "We can't rule out the possibility
of raising the disaster level to six. Depending on how the situation unfolds,
it's still possible for the level to be raised."
The Fukushima-1 plant's power and cooling systems were knocked out by the
massive earthquake and tsunami which devastated northeastern Japan on March
11. That led to a series of fires and explosions that crippled the plant and
resulted in radiation being emitted.
Elevated radiation levels have been detected in vegetables and milk
produced in areas surrounding Fukushima-1, and radioactive substances have
been detected in tap water as far away as Tokyo.
--Takeo Kumagai, firstname.lastname@example.org
--Christine Forster, email@example.com
--Thomas Hogue, firstname.lastname@example.org
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