Harry Miley, Pacific Northwest National Laboratory in Richland, Washington, Mar 7, 2014 (emphasis added): We’re surrounded by souvenirs of scientific achievement here in the National Security Building Showcase lobby. Each one of these items tells a story of scientists working quietly on projects of societal impact. This yellow thing you see behind me is an aerosol sample embedded in a filter… but this filter is unique. It was taken here a few days after the earthquake, tsunami, and nuclear disasters in Japan, and contains radioactivity that allowed us to determine the nature of the release, the magnitude of the release, but most importantly that there will be no human health impacts in North America from that disaster… The Fukushima nuclear disaster… was not something we expected. We normally work on things of societal impact invisibly… But when the disaster occurred, the things we were doing suddenly became of national importance. You could hardly imagine anything more important. In fact, it was a matter of life and death. >> Watch the video here A colleague of Miley’s at Pacific Northwest National Laboratory, Ted Bowyer, spoke about the releases during a Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) conference:

• 0:30 in – “I agree with everything that the previous speakers have said, especially the aspect that more work is necessary… We have a lot of work to do. I think we have a lot of questions that we need to answer, and there are a lot of people working on it. I also really thought it was very valuable to have this email exchange with the… other interested parties about events as they were unfolding in Japan. The accident as everyone knows was a terrible tragedy.”

• 3:30 in – Slide: Evidence of radionuclide released reached the Japanese IMS station within 2-3 days — First evidence of the plume hitting the United States came to PNNL’s experimental equipment about 1 day later (March 16)
• 4:30 in – “This is very amazing to me, having been working in the radioactive xenon monitoring field for about 17 years now. This was astounding to me… You can see background levels around 0.1 mBq/m3… Note that the peak concentration we saw was in the range of 45,000 mBq/m3 — so that is 450,000 times our background level. For me that’s astounding. We never have ever seen anything even close to that. So the concentrations went up and up and up every day, and so that was quite amazing to see this 7,000 kilometers away from the event… I only show some of the data here, but it actually persisted for weeks at very measurable levels, and filled the entire northern hemisphere and mixed into the southern hemisphere.”
• 12:00 in – “The xenon isotopic ratios appear to generally agree with the calculations. However, there is some uncertainty…We have a lot of work to do to try to understand whether there are calibration issues, whether there were physics here that we had not accounted for, etc. We do know that there are very high count rates at these detectors, which is similar to what you’d expect in an atmospheric detonation. On the other hand,the part Ididn’ttell you wasthe amount of xenon we saw was consistent with a one megaton atmospheric detonation — weobviouslywouldn’texpect tosee that high.But it was a huge amount.“

Watch Bowyer’s presentation here