Via Scientific American: Computer Model Predicts Fewer than 200 Deaths from Fukushima Radiation. Excerpt:
Immediate and future radiation from the Fukushima Daiichi nuclear disaster may result in hundreds of deaths and emerging cancer cases, according to a yearlong modeling project undertaken by researchers at Stanford University.
Started within a week of the Fukushima meltdown, the project is the most detailed model yet of the emission, transport and deposition of radioactive material from the site, accounting for complex interactions between atmospheric conditions and the microphysics of radioactive particles.
Combining the projected spread of radioactive material with a standard radiation health-effects model, co-authors John Hoeve, a recent Stanford Ph.D. graduate, and civil engineering professor Mark Jacobson calculated that between 15 and 1,300 premature deaths would occur as a result of the accident.
Within that wide range, the team poses a best guess of 130 direct deaths resulting from radiation inhalation and exposure. Those findings contest the hypothesis, circulated among some experts in the aftermath of the accident, that radioactive fallout from the Fukushima disaster would not result in any long-term human mortality.
Some mixed blessings
The full meltdown of Fukushima Daiichi reactor Units 1, 2 and 3 constituted the most serious nuclear event since the 1986 Chernobyl disaster in Ukraine, creating a contaminated "dead zone" of several hundred square kilometers and resulting in the evacuation of hundreds of thousands of people.
Yet the Fukushima disaster differed from Chernobyl in several important ways, according to the researchers. Nearly 80 percent of the radioactive material from the Japanese event ended up in the ocean, to be diluted by ocean currents, while the vast majority of Chernobyl's fallout ended up in Russia and Belarus and other neighboring states.
Fukushima's radioactive release was also limited by more stringent safety measures and a quicker response time, the report notes.
The remaining 20 percent of leaked radioactive material traveled through the air, moving with atmospheric currents, until it was eventually deposited on land. While the vast majority of grounded radioactive material has been detected in Japan, smaller traces have been detected as far away as North America and Europe.
"As you move away from Japan, you get an exponential decrease in radioactivity concentration," said Jacobson.
In the case of Fukushima, no deaths have yet been identified as the direct result of radiation exposure. But according to Jacobson, those effects can take years, even decades, to manifest.
"We know that there were 600 deaths that resulted from the evacuation," due primarily to stress and fatigue, he said. "There were also between 10 and 12 worker fatalities at the Fukushima plants. Our estimate looks at the expected deaths over a lifetime of exposure to low levels of radiation."
