That's about where the author lost me. Up to that point, he seemed to be pulling numbers from research, but then he makes a transition to pulling numbers and formulas out of his ass. For example, I'm not convinced that "if spread out over 1,000 people, so that everyone received 2.5 rem on average" is a valid deduction.
He then goes on to explain how "to know how many excess cancers there will be." I listened to an interview with a radiation expert [1] a couple weeks ago, and he made it very clear that we don't know how to make those calculations that the author of this article is claiming to know how to make. If I were to try to regurgitate the points from the interview, I'd risk spreading a misunderstanding of the issues. So instead, if you're interested in what the experts think on this subject, you can refer to the original source [1].
The spreading out effect is a direct consequence of the linear no threshold model. If you have a total dose D spread over N people, then everyone receives a dose D/N. With some constant k converting individual dose to cancer rates, you end up with an expected number of k D/N * N cases of cancer. ( So it is almost certainly wrong, however it is not understood how wrong it is.)
He then goes on to explain how "to know how many excess cancers there will be." I listened to an interview with a radiation expert [1] a couple weeks ago, and he made it very clear that we don't know how to make those calculations that the author of this article is claiming to know how to make. If I were to try to regurgitate the points from the interview, I'd risk spreading a misunderstanding of the issues. So instead, if you're interested in what the experts think on this subject, you can refer to the original source [1].
[1] http://www.pointofinquiry.org/nuclear_risk_and_reason_david_...