Cooling functions fail at Fukushima No. 2 reactorCooling functions at the quake-hit Fukushima No. 1 nuclear power plant's
No. 2 reactor have failed, the plant operator said Monday,
raising fears that the problem will lead to another explosion at the plant following a blast that occurred earlier in the day at its No. 3 reactor.Tokyo Electric Power Co. said it will inject seawater into the No. 2 reactor to cool it down and prevent the melting of its core due to overheating. Similar measures have been taken at the plant's No. 1 and No. 3 reactors and explosions occurred at both reactors during the process.
Chief Cabinet Secretary Yukio Edano said water levels had fallen but the fuel rods in the No. 2 reactor remained submerged. He also said radiation levels had not risen sharply at the plant.
A hydrogen explosion occurred Monday morning at the troubled No. 3 reactor, injuring 11 people and blowing away the roof and walls of the building that houses the reactor, but the reactor's containment vessel was not damaged.
Edano denied the possibility of a large amount of radioactive material being dispersed due to the blast. The government's nuclear safety agency said radiation levels did not jump after the explosion, indicating it did not trigger a nuclear catastrophe.
The 11:01 a.m. incident followed a hydrogen explosion at the No. 1 reactor at the same plant on Saturday.
The latest explosion prompted the Nuclear and Industrial Safety Agency to urge around 500 residents within a 20-kilometer radius to take shelter inside buildings.
TEPCO said 11 people -- workers at the site and members of the Self-Defense Forces -- sustained injuries. The Defense Ministry said one SDF member suffered broken bones.
At 11:44 a.m., the radiation level monitored at the plant was as low as 20 micro sievert per hour.
Edano said the injection of seawater to cool down the No. 3 reactor had been stopped after the blast and TEPCO is making efforts to resume the operation.
Since a magnitude 9.0 quake hit northeastern Japan last Friday, some reactors at the Fukushima No. 1 plant have lost their cooling functions, leading to brief rises in radiation levels over the weekend. As a result, the cores of the No. 1 and No. 3 reactors have partially melted.
Since the government ordered residents within a 20-km radius of the plant to evacuate Saturday in the wake of the initial blast at the plant's No. 1 reactor, around 500 people remain in hospitals and nursing care facilities within the radius, plus some residents, according to the agency.
The agency ruled out the possibility of broadening the area subject to the evacuation order for now.
The blast followed a report by the power company to the government earlier in the day that the radiation levels at the plant had again exceeded the legal limit and that pressure in the containment vessel of the No. 3 reactor had increased.
On Monday, radiation at the plant's premises rose over the benchmark limit of 500 micro sievert per hour at two locations, measuring 751 micro sievert at the first location at 2:20 a.m. and 650 at the second at 2:40 a.m., according to the report.
The hourly amounts are more than half the 1,000 micro sievert level to which people are usually exposed in one year.
The maximum level detected so far around the plant is 1,557.5 micro sievert logged Sunday.
The utility had been injecting seawater into the plant's No. 1 and No. 3 reactors to help cool their cores, where sections of the fuel rods are no longer covered by coolant water following a fall in water levels after the quake.
The seawater injection stopped at around 1 a.m. Monday due to a shortage of water left in tanks but resumed for the No. 3 reactor at 3:20 a.m., according to the nuclear safety agency.
The halt of coolant water injection apparently caused rising pressure in the reactor containment vessel and an increase in the radiation levels at the plant, the agency said.
Edano said the pressure in the No. 1 reactor's containment vessel has been stable and that seawater injection for the reactor will resume later.
==Kyodo
![[boing]](/images/smilies/nuevos/pelota_ani1.gif "pelota")
. Asi estan las cosas ahora mismo:
, pero bueno, como ponen una ventanita abajo con la TV publica japonesa, pensaràn que ya es suficiente. 
![[buaaj]](/images/smilies/nuevos2/vomitivo.gif "mas potas")
![[mad]](/images/smilies/nuevos/miedo.gif "loco")
