Fukushima nuclear plant released tiny amount of plutonium, but hot particles raise concerns
A University of Victoria marine chemist and oceanographer has concluded that a tiny bit of plutonium was dumped into the environment as a result of the 2011 nuclear disaster in Fukushima.
In a blog post on Daily Kos, Jay T. Cullen wrote that the amount of plutonium from Fukushima was 100,000 times lower than the release from the 1986 Chernobyl nuclear accident in Ukraine, and five million times lower than what resulted from atmospheric weapons tests in the last century.
Cullen, who's with UVic's school of earth and ocean sciences, based his remarks on several papers published in peer-reviewed journals.
He has been writing a series of articles on the Daily Kos website to offer insights into the effect of the Fukushima disaster on the marine ecosystem and on the North America's west coast.
"Plutonium is an alpha-emitting isotope that carries significant radiological health risks if internalized so understanding the amount released is key," he wrote in his most recent post. "Online and in some media there exists a misconception that 'massive' amounts of Pu [plutonium] escaped from the reactors."
He noted that there were 3.5 times as many plutonium isotopes in the Fukushima reactors than were in the Chernobyl plant.
Meanwhile, Vermont-based Fairewinds Energy Education has released a new video about "hot particles".
According to Fairewinds chief engineer Arnie Gundersen, a former nuclear-industry senior vice president, these dangerous particles are "scattered all over Japan and North America's west coast", but they are "difficult to detect".
The video features Marco Kalton, a civil engineer and PhD candidate at Worcester Polytechnic Institute, who specializes in examining how radioactive and chemical particles accumulate in house dust.
"In looking at indoor environments, they tend to be much more contaminated than the surroundings outside," Kalton says in the video. "Houses act like a trap and they tend to collect outdoor contaminants. And they expose people as much as 24 hours a day..."
He notes that three isotopes have been repeatedly observed in connection with the Fukushima accident: cesium 134, cesium 137, and radium 226.
Kalton explains that cesium 134 and cesium 137 are fission products that arise after a nuclear reaction; radium 226 is linked to the original uranium fuel.
He's been spreading house dust on a copper plate and exposing it to X-ray film for a week.
According to Kalton, hot particles can be discovered after positive samples are analyzed by an electron microscope, which magnifies them by up to 15,000 times.
"So we can actually, through this process, take a sample that might weigh a pound or two pounds—a half a kilo, a full kilo, and isolate as few as one or two hot particles from that entire sample," Kalton says. "And then do a full analysis and a breakdown. And that’s extremely valuable to us. It tells us a lot about what might happen if someone inhaled or ingested that particle."
A sample from Goya, Japan, which is 460 kilometres from the Fukushima plant, revealed a particularly large hot particle. It was 10 microns across.
"The particle was actually in the size range of dusts that can be inhaled and then retained in the lungs," he says. "And this is important because if you’re a health physicist and you’re calculating the dose that you would get from this particle, you’d have to consider that this particle might actually be trapped and result in a lifetime exposure."
Tests from Fukushima Prefecture and from Tokyo revealed that "about 25 percent of those samples contained at least a few measurable hot particles," Kalton explains.
He adds, however, that the one in Goya was the "worst case".
Gundersen closes the video by saying that scientific information of this calibre is not available in traditional news stories or from the plant operator, the Tokyo Electric Power Company, or the International Atomic Energy Agency.
"Fairewinds has long said that there will be significant increases in cancer in Japan as a result of the Fukushima Daiichi accident," Gundersen declares, "and this video describing just one hot particle confirms our worst fears."