Let's see - some scenarios that might fit the charter of this site and would benefit the community of this site if answered thoughtfully and not emotionally.
Hazmat scenario 1: Local facility with Nuclear material (university, medical facility, industrial site) has a spill of radioactive material. This poses two scenarios, the first being similar to chemical scenarios in that you may be displaced and cared for by the state for a while and infrastructure around the site will be affected - offline. The second is that without detection this leakage may go on for a while at low levels or be high dosage before detected by officials. This could be undetected because no material is leaking but the shielding on the containment has failed and radiation is leaking directly.
Hazmat scenario 2: Local facility (power plant, particle physics lab, weapons test range) with high energy nuclear activity goes Ka-Boom. This scenario is similar to the above but there is likely to be large unavoidable dosage without warning and combind with other disaster consequences such as fire and explosion (think chernobyl or three mile island). Disruption to infrastructure and involvement of the local emergency resources are likely to be greater.
Terrorist scenario 1: Dirty bomb - within effective zone dosage may be small but will be unavoidable. Time spent in zone is a factor to dosage. DeCon is a requirement to stop dosage. If you carry the radioactive "dirt" with you when you leave the zone then you haven't left the zone.
Terrorist scenario 2: Thermo-nuclear - If you are in the zone your cooked. If you are not cooked then this looks similar to terrorist scenario 1 above.
Nuclear War scenario 1: limited exchange; See terrorist scenarios 1 and 2.
Holocaust scenario : Not this site.
We are all vulnerable to some of these scenarios to some degree. Whether we consider these statistically likely enough to be a concern is partially a matter of our interpretation of the current geopolitical situation and partially a matter of science. Certainly the hazmat scenarios are as appropriate for the charter of this site as any other Hazmat scenario. If you consider that terrorism is a fact of our current environment in the US then the terrorist scenarios are worthy of consideration because they are a possible daily event. So far, this site has not wanted to address war-time issues.
If you are vulnerable to such scenarios (proximity to likely sources / targets) how can you be best prepared? How is this preparation different from other hazmat preparations? How can you monitor your environment so that you become aware as early as possible?
I think that we do our community a dis-service if we categorically ignore the nuclear materials risk. I think we under-estimate our colleagues on this forum if we suggest that we are in-capable of discussing these topics without devolving to a political / religious fear / ignorance flame-war. <img src="images/graemlins/smile.gif" alt="" /> Then again, perhaps I over estimate the quality of participation here? <img src="images/graemlins/wink.gif" alt="" />