A plane crash attack is no different than any other type of accident; it can be integrated in the incident response plan (much less dangerous than tsunami). Thi

A plane crash attack is no different than any other type of accident; it can be integrated in the incident response plan (much less dangerous than tsunami). This is not the big problem. The bigger problem is proliferation. All nuclear power plants produce plutonium from fuel stocks, which goes straight to the waste. Plutonium can be chemically separated from the nuclear waste, which is not quite easy, but much much easier than isotope separation. Thankfully, a single neutron capture transforms Pu-239 to Pu-240, which is unusable in nuclear weapons (if it wasn't the case, human civilization would have ended decades ago), and it is (or was) nearly impossible to separate these two isotopes. To obtain relative pure Pu-239, fuel assemblies or special U-238 rods need to be extracted early in the campaign, which is observable (unless a reactor is specifically designed for that). Unfortunately, modern laser isotope separation methods (spin chemistry, magnetic isotope effects) make it possible to separate Pu-239 from Pu-240. Most of the details are classified, but secrets can work only for a limited time.