Radiation 1,000 times above normal was detected in the control room of one plant, although authorities said levels outside the facility’s gates were only eight times above normal, spelling “no immediate health hazard.
The two nuclear plants affected are the Fukushima No. 1 and No. 2 plants, both located about 250 kilometres northeast of greater Tokyo, an urban area of 30 million people.
A total of 45,000 people living within a 10-kilometre radius of the No. 1 plant were told to evacuate today raising the number from the fewer than 6,000 people within three kilometres told to leave Friday.
In an unprecedented move, Tokyo Electric Power, which runs the plants, released some radioactive vapour to relieve building reactor pressure, but stressed the move posed no health risks.
Five reactors between both plants were vented.
Such a release has only occurred once in U.S. history, at Three Mile Island.
A sign that the Japanese are pulling out all the stops they can to prevent this accident from developing into a core melt and also prevent it from causing a breach of the containment (system) from the pressure that is building up inside the core because of excess heat,” said Mark Hibbs, a nuclear expert at the Carnegie Endowment for International Peace.
When Friday’s massive quake hit, the plants immediately shut down, along with others in quake-hit parts of Japan, as they are designed to do but the cooling systems failed, the government said.
The major fear is that fuel rods, which create heat through a nuclear reaction, could become exposed and release radioactivity.
When reactors shut down, cooling systems must kick in to bring down the very high temperatures. These systems are powered by either the external electricity grid, backup generators or batteries.
This is key to prevent a “nuclear meltdown” and radioactive release.
When Japan on Friday received news of troubles at the Fukushima No. 1 plant, it dispatched around 160 military personnel there, sending its chemical corps and an aircraft on a “fact-finding mission.”
The U.S. air force, which has many bases in Japan, delivered coolant to a Japanese plant, U.S. Secretary of State Hillary Clinton said Friday, without specifying which plant.
The UN’s International Atomic Energy Agency said Japanese officials had kept it informed of their efforts to restore power to the cooling systems while monitoring a pressure buildup.
Although the problems at the plants raised fears of a repeat of 1979’s Three Mile Island accident, experts said the situation was, so far, less serious.
Equipment malfunctions, design problems and human error led to a partial meltdown of the reactor core at the Three Mile Island plant, but only minute amounts of dangerous radioactive gases were released.
“The situation is still several stages away from Three Mile Island when the reactor container ceased to function as it should,” said Tomoko Murakami, leader of the nuclear energy group at Japan’s Institute of Energy Economics.
A similar emergency caused by an earthquake could not be repeated in Canada, officials in the industry say, adding that our country’s nuclear sites are always built on sturdy foundation. Canadian nuclear reactor sites are first geologically screened to ensure they are constructed in “seismically stable” locations, according to Atomic Energy of Canada Ltd., the country’s nuclear energy research program.
Robin Forbes, AECL spokesman, said that risk assessments are conducted and multiple safety barriers are put in place so plants can withstand hurricanes and earthquakes.
There are seven nuclear reactors in “low seismic” areas across the country, including five in Ontario, one in Quebec and one in New Brunswick, the Canadian Nuclear Safety Commission says on its website.
Each facility is constructed on a deep foundation with strong concrete floors and walls that are multiple feet thick while frequent upgrades and improvements are made to match standards, said Ted Gruetzner, spokesman of the Ontario Power Generation, which manages some nuclear sites in the province.
“I have no worries about living close to reactors. People in the industry understand that they’re very safe and that they remain so.
Agence France-Presse, with files from Reuters and Postmedia News.
Robin Forbes, AECL spokesman, said that risk assessments are conducted and multiple safety barriers are put in place so plants can withstand hurricanes and earthquakes.
There are seven nuclear reactors in “low seismic” areas across the country, including five in Ontario, one in Quebec and one in New Brunswick, the Canadian Nuclear Safety Commission says on its website.
Each facility is constructed on a deep foundation with strong concrete floors and walls that are multiple feet thick while frequent upgrades and improvements are made to match standards, said Ted Gruetzner, spokesman of the Ontario Power Generation, which manages some nuclear sites in the province.
“I have no worries about living close to reactors. People in the industry understand that they’re very safe and that they remain so.
Agence France-Presse, with files from Reuters and Postmedia News.