ID :
168797
Wed, 03/16/2011 - 22:48
Auther :
Shortlink :
https://www.oananews.org//node/168797
The shortlink copeid
Steam at Fukushima No. 3 reactor, massive water injection planned
TOKYO, March 17 Kyodo - Japan's nuclear crisis at the Fukushima No. 1 power station showed no signs of abating Wednesday, five days after a mega earthquake crippled it, with the focus shifting to how to cool the possibly overheating pools that store spent fuel rods at the already troubled No. 3 and No. 4 reactors.
What appeared to be smoke coming from the No. 3 reactor in the morning led the top government spokesman to point to the possibility of damage to the reactor's steel containment vessel, but it seemed more likely later in the day that the smoke was radioactive steam coming from the No. 3 reactor's spent fuel pool.
Cooling down the spent fuel pools is a difficult task amid the high radiation level in the area, while fears of radiation among the public appeared to escalate as some companies refused to deliver relief materials to Fukushima Prefecture even outside of the government-designated warning zone.
The government's Nuclear and Industrial Safety Agency said the first priority should be pouring coolant water into the pools at the No. 3 and No. 4 reactors, which are apparently boiling. Unless the spent fuel rods are cooled down, they could suffer damage and emit radioactive substances.
If cooling operations do not proceed well, the situation will ''reach a critical stage in a couple of days,'' an agency official said.
To address the crisis at the No. 4 reactor, plant operator Tokyo Electric Power Co. asked for the help of a special water cannon truck used by the Metropolitan Police Department to douse water on the reactor's spent fuel rod pool. The truck arrived at the Fukushima power station early Thursday.
The U.S. military will also operate a Global Hawk unmanned high-altitude reconnaissance aircraft, possibly on Thursday, to take images of the inside of the building that houses the No. 4 reactor, according to Japanese government sources.
The building housing the No. 4 reactor suffered what appeared to be a hydrogen explosion on Tuesday. A satellite image provided by TEPCO on Wednesday showed the crumbling concrete walls.
Chief Cabinet Secretary Yukio Edano said Wednesday morning that the smoke from the nuclear plant was identified from about 8:30 a.m. and it was possible that ''steam has been released from the (No. 3) reactor's containment vessel.''
But the government announced later that the possibility of serious damage to the containment vessel is ''low,'' as radiation levels did not continue rising.
At 12:30 p.m. Wednesday, the radiation level reached 10,850 microsievert per hour at the plant's entrance, but it later dropped below 1,500 microsievert at 4:20 p.m.
The highest level on Wednesday was lower than the 400,000 microsievert per hour -- equivalent to 400 times the level to which people can be safely exposed in one year -- recorded Tuesday, the highest level so far reported at the plant.
The nuclear agency said later Wednesday that the reason for the brief surge in the radiation level remains unknown.
Edano said in the morning that the government has no plans at the moment to expand the evacuation zone which currently covers areas within a 20 kilometer radius of the plant.
The government at one point studied a plan to deploy Ground Self-Defense Force choppers to spray water over the spent fuel pools but the Defense Ministry said in the afternoon it had given up on the idea due to the high radiation level.
Adding to concern, a fire broke out earlier Wednesday at the No. 4 reactor, which was already posing the risk of leaks of high-level radioactive materials, but flames were no longer visible about 30 minutes later, according to TEPCO. Fire was first seen around the same location Tuesday.
Of the six reactors at the Fukushima No. 1 nuclear plant, part of the No. 2 reactor's containment vessel, key to enclosing harmful radioactive substances, has been compromised. More specifically, the pressure-suppression chamber connected to the vessel was damaged following an apparent hydrogen explosion early Tuesday.
An estimated 70 percent of the nuclear fuel rods have been damaged at the plant's No. 1 reactor and 33 percent at the No. 2 reactor, Tokyo Electric said Wednesday.
The cores of the No. 1, No. 2 and No. 3 reactors are believed to have partially melted with their cooling functions lost in the wake of Friday's magnitude 9.0 earthquake and tsunami.
The nuclear agency said Wednesday that the water level had dropped in the No. 5 reactor, which was not in service when the killer quake jolted northeastern Japan, posing the risk of overheating. The agency said it will closely monitor data on the reactor to prevent the problems that occurred at other reactors.
The impact of the recent release of radioactive substances continued to widen, with the Fukushima prefecutural government announcing that it had detected a small amount of radioactive substances -- iodine and cesium -- from tap water extracted at 8 a.m. in the city of Fukushima. The substances were not detected in water taken in the afternoon.
Meanwhile, the science and technology ministry said the radiation level in Namie, Fukushima Prefecture, on Tuesday was around 6,600 times higher than normal. The town lies within the area where residents have been urged to stay indoors.
Edano said the level ''would not have immediate effects on the human body'' and noted that there seems to be some ''overreaction'' to radiation fears.
Even outside the zone where the government has recommended that people remain indoors, there are cases where the distribution of essential goods has stopped, Edano said.
What appeared to be smoke coming from the No. 3 reactor in the morning led the top government spokesman to point to the possibility of damage to the reactor's steel containment vessel, but it seemed more likely later in the day that the smoke was radioactive steam coming from the No. 3 reactor's spent fuel pool.
Cooling down the spent fuel pools is a difficult task amid the high radiation level in the area, while fears of radiation among the public appeared to escalate as some companies refused to deliver relief materials to Fukushima Prefecture even outside of the government-designated warning zone.
The government's Nuclear and Industrial Safety Agency said the first priority should be pouring coolant water into the pools at the No. 3 and No. 4 reactors, which are apparently boiling. Unless the spent fuel rods are cooled down, they could suffer damage and emit radioactive substances.
If cooling operations do not proceed well, the situation will ''reach a critical stage in a couple of days,'' an agency official said.
To address the crisis at the No. 4 reactor, plant operator Tokyo Electric Power Co. asked for the help of a special water cannon truck used by the Metropolitan Police Department to douse water on the reactor's spent fuel rod pool. The truck arrived at the Fukushima power station early Thursday.
The U.S. military will also operate a Global Hawk unmanned high-altitude reconnaissance aircraft, possibly on Thursday, to take images of the inside of the building that houses the No. 4 reactor, according to Japanese government sources.
The building housing the No. 4 reactor suffered what appeared to be a hydrogen explosion on Tuesday. A satellite image provided by TEPCO on Wednesday showed the crumbling concrete walls.
Chief Cabinet Secretary Yukio Edano said Wednesday morning that the smoke from the nuclear plant was identified from about 8:30 a.m. and it was possible that ''steam has been released from the (No. 3) reactor's containment vessel.''
But the government announced later that the possibility of serious damage to the containment vessel is ''low,'' as radiation levels did not continue rising.
At 12:30 p.m. Wednesday, the radiation level reached 10,850 microsievert per hour at the plant's entrance, but it later dropped below 1,500 microsievert at 4:20 p.m.
The highest level on Wednesday was lower than the 400,000 microsievert per hour -- equivalent to 400 times the level to which people can be safely exposed in one year -- recorded Tuesday, the highest level so far reported at the plant.
The nuclear agency said later Wednesday that the reason for the brief surge in the radiation level remains unknown.
Edano said in the morning that the government has no plans at the moment to expand the evacuation zone which currently covers areas within a 20 kilometer radius of the plant.
The government at one point studied a plan to deploy Ground Self-Defense Force choppers to spray water over the spent fuel pools but the Defense Ministry said in the afternoon it had given up on the idea due to the high radiation level.
Adding to concern, a fire broke out earlier Wednesday at the No. 4 reactor, which was already posing the risk of leaks of high-level radioactive materials, but flames were no longer visible about 30 minutes later, according to TEPCO. Fire was first seen around the same location Tuesday.
Of the six reactors at the Fukushima No. 1 nuclear plant, part of the No. 2 reactor's containment vessel, key to enclosing harmful radioactive substances, has been compromised. More specifically, the pressure-suppression chamber connected to the vessel was damaged following an apparent hydrogen explosion early Tuesday.
An estimated 70 percent of the nuclear fuel rods have been damaged at the plant's No. 1 reactor and 33 percent at the No. 2 reactor, Tokyo Electric said Wednesday.
The cores of the No. 1, No. 2 and No. 3 reactors are believed to have partially melted with their cooling functions lost in the wake of Friday's magnitude 9.0 earthquake and tsunami.
The nuclear agency said Wednesday that the water level had dropped in the No. 5 reactor, which was not in service when the killer quake jolted northeastern Japan, posing the risk of overheating. The agency said it will closely monitor data on the reactor to prevent the problems that occurred at other reactors.
The impact of the recent release of radioactive substances continued to widen, with the Fukushima prefecutural government announcing that it had detected a small amount of radioactive substances -- iodine and cesium -- from tap water extracted at 8 a.m. in the city of Fukushima. The substances were not detected in water taken in the afternoon.
Meanwhile, the science and technology ministry said the radiation level in Namie, Fukushima Prefecture, on Tuesday was around 6,600 times higher than normal. The town lies within the area where residents have been urged to stay indoors.
Edano said the level ''would not have immediate effects on the human body'' and noted that there seems to be some ''overreaction'' to radiation fears.
Even outside the zone where the government has recommended that people remain indoors, there are cases where the distribution of essential goods has stopped, Edano said.
