The Only Thing We Have to Fear is Nuclear Meltdown
Friday’s earthquake damaged a nuclear power plant in Fukushima, and the effort to safely shut down the reactors has been a top story on Japanese news broadcasts ever since. As of this posting, Tepco was still working to cool down reactors that have experienced coolant failures. Chief Cabinet Secretary Yukio Edano has said it is “highly possible” that one of the reactors has experienced a partial meltdown:
“Because it’s inside the reactor, we cannot directly check it but we are taking measures on the assumption of the possible partial meltdown,” he said.
Although there might be a partial meltdown and some radiation leakage, it apparently will not be as bad as Chernobyl:
The Fukushima Daiichi No. 1 reactor has a better “containment system than Chernobyl but on the scale of most reactors in this country, it’s not as strong as most of them,” said Ken Bergeron, a physicist and former scientist at the Sandia National Laboratories, where he worked on nuclear-reactor accident simulation.
“If the containment doesn’t survive, we have a worst-case scenario” of a meltdown, Bergeron said in a Saturday conference call with other U.S. nuclear scientists to discuss the situation.
Tepco has said the containment is intact.
[...]
Thousands of residents within a 20-kilometer radius of the reactor have been evacuated as a precaution. But Dr. Kemper of Florida State University said in a separate interview that in the event of a large-scale radiation leak, people should barricade themselves into buildings and seal the windows until evacuation crews arrive.
The specter of huge environmental fallout on the scale of Chernobyl is unlikely, though.
The Chernobyl reactor used carbon to slow down neutrons, a key part of the fission reaction. In that disaster, a fire ignited the carbon and created radioactive soot that was carried afar by winds.
The nuclear core in many modern reactors, including the ones in Japan, is enclosed by a steel containment vessel. Today’s reactors also use water instead of carbon to slow down neutrons, so there is no big danger of the emanation of radioactive soot from the Fukushima plant.
A full meltdown at the Japanese facility would still release radioactive gases, but those tend to dissipate in the atmosphere. For example, there was a small amount of radiation released in the 1979 Three Mile Island disaster in Pennsylvania, but post-release assessments suggested it didn’t have any real health or environmental impact. About half of the core melted during the early stages of that accident.
If the Japanese nuclear core were to melt, certain radioactive materials, such as iodine, strontium and cesium, would also be released. These particles are one-quarter the size of a grain of salt and can be carried by winds. The larger the grains, the more quickly they would fall out of the air.
Dr. Kemper noted that the wind tends to blow west to east in Japan, and so a good deal of the radioactive particles would drift out to sea. Consequently, there probably wouldn’t be much fallout in Japan’s densely populated areas to the south.
Unlike an accident that releases chemical toxins, a nuclear-plant disaster has one advantage: Radiation levels can constantly and precisely be measured.
Should we be terrified? No, says Glenn Sjoden, Professor of Nuclear and Radiological Engineering at Georgia Institute of Technology, in this interview with CNN:
Professor Sjoden says he doesn’t believe that people are in serious or mortal danger. That includes people who live near the power plant. He does not think anyone should panic about this.
But what if the experts are wrong? What if there really is going to be a huge meltdown, followed by a giant release of radiation into the atmosphere? Even if a horrible nuclear disaster did occur, it seems that our fears are far greater than the actual risks, argues David Ropeik in a Scientific American blog post:
We know from studying the survivors of (nuclear) bombings, who were bathed in horrific doses of high level radiation – far worse than anything that could come from the Daiichi plant (or that came out of Chernobyl) – that ionizing radiation from nuclear energy is a carcinogen, but a relatively weak one. The roughly 100,000 survivors of the two atomic bomb blasts are known in Japan as hibakusha, and they are honored, and given special rights.
They have also been extensively studied, and 66 years later, by comparing them to cancer rates among Japanese not exposed to radiation, public health researchers estimate that only about 500 of the hibakusha died prematurely from cancer due to radiation exposure. Radiation-induced cancer killed roughly half of one percent of the exposed population. (This research is done by the Radiation Effects Research Institute, a Japanese organization supported by international public health agencies)
We also know that many of the children of hibakusha women pregnant at the time they were exposed suffered horrible birth defects. Studies of the atomic bomb survivors have also taught us, however, that there is apparently no generational genetic impact from radiation exposure. Kids born to parents who got pregnant after the exposure, were normal.
Based on studies of atomic bomb survivors, the World Health organization estimates the maximum lifetime death toll from cancer due to radiation exposure from Chernobyl, of roughly 800,000 people, will be about 4,000.
So, even if those of us in the region are exposed to radioactivity on a Chernobyl-like scale, the actual number of people who develop cancer will be low. I suppose that should make some people feel less scared.
A couple scary pictures
Over on Google News, the images used by sites like MoneyControl.com are producing preview thumbnails that are enough to make viewers very uneasy:
There also seems to be a prankster out there that created a “fallout map” warning Americans of a radiation cloud that will be heading their way. Of course, it is a hoax, not actually based on real data:
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