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.
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.
Read more and watch video.