Original URL: https://www.theregister.com/2011/08/02/nyt_nrc_meltdown_report/

Good news: A meltdown would kill fewer than we thought

So this is it, we’re all not all going to die

By Richard Chirgwin

Posted in Science, 2nd August 2011 01:00 GMT

Even if the worst happens, the death and destruction from a nuclear power station meltdown won’t be as bad as previously modeled, according to America’s Nuclear Regulatory Commission (NRC).

In a draft report given to the New York Times, the NRC has decided that a meltdown would release far less caesium 137 than previously thought. Most caesium would remain within a reactor’s containment, the report suggests, with only one to two percent escaping. Previously, the NRC had assumed that as much as 60 percent of the caesium in a reactor could escape in a meltdown.

In fact, if the report’s computer modeling and engineering analysis is correct, a meltdown might not even cause deaths in the immediate vicinity of a reactor. This conclusion is based on the belief that most people living within ten miles of a failing reactor would have time to evacuate. The most likely cause of a meltdown is a complete loss of power to a facility, resulting in a cooling failure (as famously happened in Fukushima) – but since this isn’t an instantaneous process, the NRC believes evacuation would be possible.

The New York Times also reports that with fewer people likely to be exposed to high levels of radiation in a meltdown, the likelihood of citizens developing cancers in the aftermath is also lower: from the previous estimate, that one person in every 167 living within ten miles would have sufficient exposure for a “latent cancer”, the NRC now believes the figure to be one person in every 4,348.

As with its previous estimates, the NRC’s work comes from modeling rather than observations: even with Fukushima as the headline for nuclear power disasters, there haven’t been enough accidents for any large-scale statistical studies of the likelihood of different failure scenarios. However, the NRC report has concluded that power loss, rather than the failure of pipes supplying cooling water, is the most likely cause of a meltdown.

The report was obtained under a freedom-of-information request by the Union of Concerned Scientists, which remains unconvinced by the draft report. The UCS believes tighter safeguards for America’s nuclear power plans is still required.

The final NRC report is due next April. ®