I've watched this interesting (but long) talk by Brian Sheron, retired director of Nuclear Regulatory Research:<p><a href="https://www.youtube.com/watch?v=ryI4TTaA7qM" rel="nofollow">https://www.youtube.com/watch?v=ryI4TTaA7qM</a><p>It gives me a better understanding of the risk of nuclear power, particularly for current US reactors, and what our regulatory agencies actually focus on: really it's on preventing direct radiation induced deaths, and not so much on property damage. So: It's not so much that accidents directly kill people, instead they kill the land. The idea is that loss of cooling incidents are contained for a significant amount of time- at least 8 hours. I'm dubious, but this is thought to be enough time to evacuate people from the land that will eventually become contaminated. Only when people move back do people die, and then only from increased cancer risk (Brian says this becomes an EPA problem). So now the land is lost, because who would move back? [of course this focuses only on deaths from radiation, and not for example, deaths caused by stress to elderly people forcibly relocated].<p>I did not remember when people were evacuated after the Fukushima accident, but it was pretty quick, here is a timeline:<p><a href="https://www.oecd-nea.org/news/2011/NEWS-04.html" rel="nofollow">https://www.oecd-nea.org/news/2011/NEWS-04.html</a><p>There is another question I'm still trying to answer. If the final heat sink is lost (someone blows up a dam), can the reactor be shut down without incident, assuming no blackout? This would require that the decay heat is spread across a large enough surface area. I'm not sure if the containment building provides such an area (a 1000 MW reactor generates ~70 MW decay heat after shutdown). It reminds me that this is another area that NRC does not focus on: "terrorist attacks are a military problem".<p>Edit: well I answered my own question from wikipedia entry on containment building: "While the containment plays a critical role in the most severe nuclear reactor accidents, it is only designed to contain or condense steam in the short term (for large break accidents) and long term heat removal still must be provided by other systems." So if the heat sink is a man-made lake held by dam, it's a big risk (of course dam loss would cause direct loss of life anyway). I was wondering about this because my inlaws live near Duke Energy's Oconee Nuclear Station, on man made Lake Keowee <a href="https://en.wikipedia.org/wiki/Lake_Keowee" rel="nofollow">https://en.wikipedia.org/wiki/Lake_Keowee</a>