Mar 14th 2011 – 7:59PM
CBC News
Japan's nuclear safety agency said late Monday that another explosion has been heard at the stricken Fukushima Daiichi power plant - the same facility where two previous explosions have stoked concerns of a possible meltdown.Technicians had been desperately working to prevent uranium rods in the plant's Unit 2 reactor from overheating after they were exposed twice Monday.
The fuel rods were exposed after a steam vent in the reactor wouldn't open. Water levels were restored after they first dropped at the reactor, but the rods remained exposed Monday night after the second episode, officials said.
"Units 1 and 3 are at least somewhat stabilized for the time being," said Nuclear and Industrial Agency official Ryohei Shiomi. "Unit 2 now requires all our effort and attention," he said before the latest blast.
Japanese Prime Minister Naoto Kan told reporters his government - along with the Tokyo Power Electric Co. - will set up a joint response centre to better manage the nuclear crisis. Kan said he will personally lead operations at the centre.
Officials had declared states of emergency at six Fukushima reactors - three at Dai-ichi and three at the nearby Fukushima Daini complex - after Japan was hit Friday by an 8.9 magnitude earthquake centred offshore and resultant tsunami. The main cooling systems and backup generators at the reactors were knocked out by the twin disasters.
Most of the attention in the past three days has been focused on Daiichi units 1 and 3. A complete meltdown - the melting of the radioactive core - could release radioactive contaminants into the environment and pose major, widespread health risks.
Japanese officials are using all available resources to monitor the situation, the country's ambassador to Canada said Monday.
"We are in close contact with not only American experts but also and especially with [the International Atomic Energy Association]... so that everybody knows what's going on," Kaoru Ishikawa told CBC News Network. "We are using the wisdom of all available engineers."
In another development, officials warned Monday that the death toll from the earthquake and resulting tsunami is likely to exceed 10,000.
Unit 3 reactor rocked by earlier explosion
Earlier Monday, the second explosion in three days rocked the Fukushima Dai-ichi plant, sending a massive cloud of smoke into the air and injuring 11 workers.
The blast at the Unit 3 reactor, which authorities had been trying to cool with seawater, triggered an order for hundreds of people to stay indoors, said Chief Cabinet Secretary Yukio Edano.
"Clearly the situation still remains serious as it was at Unit 1 on Saturday and Unit 3 on Sunday," McMaster University nuclear safety expert John Luxat told CBC News.
"The hydrogen explosion is an indication at these other two reactors that some fuel was exposed to become uncovered by water, heated up, and as a result of that [produced] hydrogen gas. The issue with the third reactor will be how long the fuel remains exposed, how hot it gets, and how much hydrogen is generated."
Radiation still within legal limits: plant operator
The operator of the Fukushima Dai-ichi plant said radiation levels at the affected unit were still within legal limits Monday.
Operators knew the seawater flooding would cause a pressure buildup in the reactor containment vessel - and potentially lead to an explosion - but felt they had no choice if they wanted to avoid a complete meltdown. In the end, the hydrogen in the released steam mixed with oxygen in the atmosphere and set off the blast.
The inner containment shell surrounding the Unit 3 reactor was intact, Edano said, allaying some fears of the risk to the environment and public. But the outer building around the reactor appeared to have been devastated, with only a skeletal frame remaining.
Mark Hibbs, a senior associate in the Carnegie Endowment for Peace's Nuclear Policy Program based in Berlin, spoke with the CBC's Suhana Meharchand.
"The situation so far, according to the Japanese authorities, is that the reactor vessel where the fuel rods is, is intact," he said. "That's very good news."
The concern, he said, is that because the site has been buffeted by both an earthquake and a tsunami, the precise extent of damage to the containment vessels isn't known.
"They are confident after looking at it that they haven't seen any damage," he said. "But there are some uncertainties, because unlike the reactor in the United States at Three Mile Island, which experienced a similar incident in 1979, here in this case, this reactor was buffeted first by an earthquake and then a tsunami, and no one can be absolutely sure that the structure in those reactor buildings are perfectly sound."
Radiation 'well under' reportable levels
Tokyo Electric Power said radiation levels at Unit 3 were well under the levels where a nuclear operator must file a report to the government.
A similar explosion occurred Saturday at Unit 1, injuring four workers, causing mass evacuations and destroying much of the outer building.
More than 180,000 people have evacuated the area in recent days, and up to 160 may have been exposed to radiation - pouring misery onto those already devastated by the twin disasters.
Japan's meteorological agency reported the prevailing wind in the area of the stricken nuclear plant was heading east - to the Pacific.
U.S. vessel moved amid radiation fears
Seventeen U.S. military personnel involved in helicopter relief missions were found to have been exposed to low levels of radiation upon returning to the USS Ronald Reagan, an aircraft carrier about 160 kilometres offshore.
U.S. officials said the exposure level was roughly equal to one month's normal exposure to natural background radiation in the environment, and after scrubbing with soap and water, the 17 were declared contamination-free.
But as a precaution, the U.S. said the carrier and other U.S. 7th Fleet ships involved in relief efforts had shifted to another area.
While Japan has aggressively prepared for years for major earthquakes, reinforcing buildings and running drills, the impact of the tsunami - which came so quickly that not many people managed to flee to higher ground - was immense.
By Monday, officials were clearly overwhelmed by the scale of the crisis, with millions of people having spent three nights without electricity, water, food or heat in near-freezing temperatures.
Officials in one devastated town said they were running out of body bags.
Edano said no Fukushima reactor was near having a complete meltdown, and he was confident of escaping the worst scenarios.
International scientists say there are serious dangers but little risk of a Chornobyl-style catastrophe. Chornobyl, they note, had no containment shell around the reactor.
"The likelihood there will be a huge fire like at Chornobyl or a major environmental release like at Chornobyl, I think that's basically impossible," said James F. Stubbins, a nuclear energy professor at the University of Illinois.
And, some analysts noted, the length of time since the nuclear crisis began indicates that the chemical reactions inside the reactor were not moving quickly toward a complete meltdown.
AFP PHOTO /YOMIURI SHIMBUN
A fishing boat rests surrounded by debrid in the city of Kamaishi in Iwate prefecture on March 12, 2011 a day after a massive 8.9 magnitude earthquake and tsunami hit the region. An explosion at a Japanese nuclear plant triggered fears of a meltdown on March 12, after the massive earthquake and tsunami left more than 1,000 dead and at least 10,000 unaccounted for.
http://xml.channel.aol.com/xmlpublisher/fetch.v2.xml?option=expand_relative_urls&dataUrlNodes=uiConfig,feedConfig,entry&id=991216&pid=991215&uts=1300147945
http://cdn.channel.aol.com/cs_feed_v1_6/csfeedwrapper.swf
Japan Earthquake and Tsunami in Photos
A fishing boat rests surrounded by debrid in the city of Kamaishi in Iwate prefecture on March 12, 2011 a day after a massive 8.9 magnitude earthquake and tsunami hit the region. An explosion at a Japanese nuclear plant triggered fears of a meltdown on March 12, after the massive earthquake and tsunami left more than 1,000 dead and at least 10,000 unaccounted for.
AFP PHOTO /YOMIURI SHIMBUN
Jens Meyer, AP
Epic Tsunami Totals Japan
A video image shows the coastline and tsunami caused by an earthquake, on March 11, 2011 in Sendai, Japan. The earthquake, measuring 8.9 on the Richter Scale, hit the northeast coast of Japan causing Tsunami alerts throughout countries bordering the Pacific Ocean.
This aerial shot shows boats being carried away at a flooded marina in Hitachinaka city in Ibaraki prefecture on March 11, 2011 after a tsunami hit following an earthquake.
Commuters make their way after train services are suspended after an 8.9 magnitude earthquake on March 11, 2011 in Tokyo, Japan.
Vehicles are crushed by a collapsed road at a carpark in Yabuki, in southern Fukushima Prefecture on March 11, 2011 after an earthquake rocked Japan. The earthquake hit Japan, unleashing a monster 10-metre high tsunami that sent ships crashing into the shore and carried cars through the streets of coastal towns.
Fishing boats and vehicles are carried by a tsunami wave at Onahama port in Iwaki city, in Fukushima prefecture, northern Japan on March 11, 2011.
A shop owner chats with a neighbour as the pedestrian road has collapsed in the massive 8.9-magnitude earthquake in Urayasu city, Chiba prefecture on March 11, 2011.
Residents check the damaged done on a road a house in Sukagawa city, Fukushima prefecture, in northern Japan on March 11, 2011.
A pedestrian road has collapsed in the massive 8.9-magnitude earthquake in Urayasu city, Chiba prefecture on March 11, 2011.
A tsunami, tidal wave smashes vehicles and houses at Kesennuma city in Miyagi prefecture, northern Japan on March 11, 2011.
Local residents watch the devastation provoked by a tsunami tidal wave smashing vehicles and houses at Kesennuma city in Miyagi prefecture, northern Japan on March 11, 2011.
"We're now into the fourth day. Whatever is happening in that core is taking a long time to unfold," said Mark Hibbs, a senior associate at the nuclear policy program for the Carnegie Endowment for International Peace. "They've succeeded in prolonging the timeline of the accident sequence."
But despite official assurances, many residents expressed fear over the situation.
Worried about radiation
"First I was worried about the quake," said Kenji Koshiba, a construction worker who lives near the plant. "Now I'm worried about radiation."
He spoke at an emergency centre in Koriyama, about 60 kilometres from the most troubled reactors.
Overall, more than 1,500 people had been scanned for radiation exposure in the area, officials said.
The UN nuclear agency said a state of emergency was also declared Sunday at another complex, the Onagawa power plant, after higher-than-permitted levels of radiation were measured there. It said Japan informed it that all three of those reactors there were under control.
With files from The Associated Press
Copyright: (C) Canadian Broadcasting Corporation, http://www.cbc.ca/aboutcbc/discover/termsofuse.html
No comments:
Post a Comment