Earlier today, Earth & Industry had the chance to participate in a call with leading international radiation experts and learn what they had to say about the crisis at the Fukushima Daiichi Plant and the threats posed by nuclear fallout.
The Physicians for Social Responsibility news event was held to address concerns about misleading and incomplete information that is being provided about the Japanese nuclear catastrophe and was led by Dr. Ira Helfand, lifelong nuclear energy educator and former president of Physicians for Social Responsibility; Dr. David Richardson, associate professor of epidemiology at the School of Public Health, University of North Carolina; and Dr. Marvin Resnikoff, an international consultant on radioactive waste issues.
A streaming audio replay of this telenews conference will be available here. Read on to learn more about areas of concern and the impact of this disaster.
2,000 Tons of Nuclear Materials at Fukushima Daiichi
Six reactors, seven fuel pools and a storage tank total almost 2,000 tons of nuclear material. The reactors alone are storing 1000 times as much nuclear energy as the Hiroshima bomb released in one concentrated dose and include waste that has been undergoing nuclear fission for 3 years. Continued exothermic reactions make for more radioactive contaminants and contribute to the gravity of the daunting situation in Japan.
The Heat is On---For Months!
Steam explosions and burn off from exposed fuel pools are the hazards causing the most concern.
The International Atomic Energy Agency has confirmed a partial meltdown in reactors 1, 2 and 3 and workers have already experienced two fires at Reactor 4. They can no longer get close to problem areas because water, which serves to shield workers and cool the fuel, is not being dropped and gamma radiation is extremely high. As the water evaporates it exposes the nuclear fuel and uranium rods begin to burn, emitting more heat and radioactive cesium. Uranium is then able to mix with water and begin the reaction that sends radiation into the atmosphere.
Reactor #3 is especially dangerous, as it is fueled with a combination of Mox and uranium. Mox fuel releases plutonium, which has a 24,200 year half-life and can cause lung cancer at extremely low doses.
Roofless spent-fuel pools sit at the top of the reactors (70-80 feet up), if these pools aren't cooled to a temperature below 1800 F, hydrogen will be created and more explosions will occur.
Though water cannons are being deployed, Japan is having trouble resupplying water to cool the affected areas, which leads Dr. Resnikoff to believe that temperatures could be soaring for months.
External Ionizing Radiation and Human Health
There remains a lack of information on the environmental levels of external ionizing radiation--the kind that moves through the body in waves (think: gamma and beta rays)--but knowing these measurements of total body radiation exposure doesn't indicate personal health risk as much as knowing the exposure rate to specific tissues. We do know that the "Fukushima 50" (the workers left battling the meltdown) are in a grave situation, facing hazards of extreme heat, explosions and fires, and that the workers must move through some sites in a matter of minutes to avoid acute radiation.
Radioactive Isotopes and Ambient Radiation
Ambient radiation and the dispersion of radioactive isotopes will cause numerous health problems, warns nuclear expert, Dr. Ira Helfand. Radioactive isotopes may be inhaled, ingested, or absorbed into the bloodstream through open wounds and pose more of a threat to the Japanese population than radiation waves or beams. Land 100 miles downwind of Chernobyl was contaminated with radioactivity and is still not safe to use, "if winds blow in the direction of Tokyo, it is conceivable that large parts of Tokyo could be contaminated in this way," he says. A forecast for easterly winds could be the city's saving grace.
Exactly how much ambient radiation will be released is impossible to say and measured levels vary dramatically moment to moment. We will likely not know the volume released to the environment until the materials that remain stored at Fukushima are assessed. The highest levels noted by Dr. Helfand are 40 rems-- a dose that would cause sickness after 2.5 hours of exposure.
Of the 200 different radioactive isotopes that could be released, 4 pose real risk to human health:
Iodine 131 - concentrates in the thyroid, has a half-life of 8 days, leads to thyroid cancer
Strontium 90 - concentrates in bone marrow, has a half-life of 90 years, leads to bone cancer and leukemia
Cesium 137 - prevalent in all tissues, has a half-life of 30 years, can cause multiple cancers
Plutonium 239 - concentrates in the lungs, has a half-life of 24,200 years, low doses lead to lung cancer
Image Credit: daveeza via Flickr