Title: Japan’s Black Dust, with Marco Kaltofen
Source: Fairewinds Energy Education
Date: July 10, 2013
Marco Kaltofen, President at Boston Chemical Data Corp. & Doctoral student researcher at Worcester Polytechnic Institute: [...] We kept hearing reports about something unusual, a black dust [...] we finally got a very small sample of that [...]
What’s different about this material is unlike a lot of the soil and dust samples we’ve gotten, there’s a real uniformity to this stuff. It’s a single substance. It’s not a mix of mineral particles and pieces of dead bugs and plant matter and dust particles. It’s actually very homogenous and uniform when you look at it under the microscope. And it doesn’t look like the surrounding soils. And it is much more intensely radioactive than any other soil or dust sample we’ve gotten from around Fukushima Daiichi. So this material is different. It’s not a natural soil. There’s something unusual happening with this stuff. [...]
The sample had fairly high levels of radium 226. Now that’s not a radioisotope that we hear as much about. The radium 226 has almost as much activity as the radioactive Cesium in the sample. Radium 226 is a degradation product of uranium and we can’t really detect the uranium directly. [...] And this tells me that this particle contains not only fission waste products from the reactor but very likely contains a concentrated unburned nuclear fuel. And that’s unusual. This sample had by far the highest level of uranium daughters that we’ve seen in a dust or soil sample. We’re actually seeing material that might well have come from inside a failed fuel assembly.
Arnie Gundersen, Fairewinds’ Chief Engineer: Okay. When I hear that, that’s clear evidence that the containment was breached. The interesting thing to me is that when I hear black, I think of like algae or fungi or something like that. But you’re saying this is not an organic substance. Is that right?
Kaltofen: No. It’s not an organic substance. It’s a mixture of very small particles and just the way they aggregate gives it the appearance of being black, but it’s – it probably – I won’t say optical illusion, but it’s an optical effect of the size of the particles and the way they’re joined together. [...]
Gundersen: Are these particles light enough for people to ingest them or breathe them in?
Kaltofen: Well, certainly they could be ingested [...] right now I would say they’re much more an ingestion hazard. And that usually tends to target children and agricultural workers. [...] A child on average consumes between 100 and 200 milligrams of soil a day because of hand-to-mouth activity. So that’s something to really think about.
Published: July 11th, 2013 at 10:59 am ET