Friday, March 25, 2011
Image via WikipediaJapan Reactor Nuclear Core May Have Been Breached : NPR
The operators of the damaged Fukishima Dai-chi power plant say there's evidence that radioactive water leaking from the third reactor came from its core. This reactor has been the source of major concern since the March 11 earthquake and tsunami that devastated northern Japan, and led to the current crisis at the power facility.
Officials say they have not found evidence of an actual breach in the reactor. There are many pipes and connections leading to the core that could be the source of leaking water.
But the utility also found extremely high levels of radiation in the water, and detected radioactive isotopes that are not ordinarily present in cooling water.
Since the accident began, there's been considerable speculation as to whether radiation leaks are coming from the reactors themselves, or from spent fuel stored in pools that may have been damaged.
The news comes a day after three workers were exposed to high levels of radioactivity while laying electrical cable in the basement of a building near Unit 3. Two of the men were taken to a local hospital for treatment of possible radiation burns. They were then brought to Japan's National Institute of Radiological Sciences in the Tokyo area.
In a statement on Friday, Tokyo Electrical Power Co., or TEPCO, which runs the plant, indicated that the workers had ignored high readings on their dosimeters, which measure the presence of radiation. The men were employed by a contractor for TEPCO. Their condition since they were brought in for treatment on Thursday is unknown.
The Nuclear Safety Commission of Japan also expanded its call for a voluntary evacuation around the plant, to a radius of 30 kilometers, about 18 miles. Since March 15, residents living within 20 kilometers — about 12 miles — have been urged to leave the area, and those living within the 30-kilometer range had been told to remain indoors.
Chief Cabinet Secretary Yukio Edano says local governments are being told to call for voluntary evacuations 30 kilometers out. The government said that the main concern was not radiation exposure, but that services in this area had been severely disrupted by the earthquake, tsunami and the nuclear crisis.
The U.S. government has also told its citizens to stay 50 miles away from the plant.
Food And Water Concerns
Radiation leaks have contaminated some food and water around the plant. Tokyo residents were warned on Wednesday that tap water had tested high for radioactivity, and that they should not allow infants to drink the water.
That order was rescinded the next day when readings dropped. But water systems in a number of cities continue to test above the levels considered safe for small children.
Japan has restricted the sale and consumption of produce, fruit and milk produced around the plant. And the United States and other countries have banned the import of some food products from the affected area.
Damage To Reactor Buildings
Japan's Self-Defense Forces released a video of the damaged reactor buildings, shot from a military helicopter. The film shows extensive damage to many of the buildings.
The roofs of several reactor buildings have been reduced to the steel framework, and steam is clearly leaking from a number of places. Since the earthquake, there have been a number of explosions traced to leaking hydrogen within the reactor buildings.
Official say that work continues to revive the cooling equipment that lost power after the natural disaster struck. External power has been restored to all six reactors.
Technicians are also beginning to pump fresh water, instead of seawater, into Unit 1. TEPCO has been injecting seawater into some of the reactors to keep nuclear fuel from overheating, but there's concern that salt deposits from the seawater could make it more difficult to move heat away from the fuel. The company plans to replace seawater with fresh water at Units 2 and 3, which have also suffered fuel damage.
Relief officials now say the confirmed death toll from the earthquake and tsunami has reached 10,000, with more than 17,000 people still missing. Nearly 300,000 people are believed homeless, and the number of evacuees will now increase, with the government's decision to expand the safety zone around the plant.