Why use software when you can use hardware (5 men with AK's storm a nuclear reactor and use explosives to damage the cooling systems and containment vessel) DHS is already training for situations like these, but security has not been beefed up at US nuclear reactors. By the time local LEO responded it would be too late. SWAT would arrive just in time to eliminate the 5 threats and then see the coolant boiling out of a damaged reactor. Terrorists as we know do things in bulk, ie multiple airplanes not just 1, therefor I assume they would go after 5 reactors, not just 1, complicating an already complex NBC threat.
I have a NBC suit and Mask for everyone in my family with a dozen filters per person. This is not for Japan or some other crazy event, it is because the terrorists are already planning their next move which DHS, CIA, etc. think may be on nuclear reactors and/or detonating a dirty bomb in a major city or 5.