OK, I admit it; I am a nerd. I have been interested in Sterile neutrinos since MiniBooNE hinted at their existence. But enough of that. The last paragraph got me thinking about Iran and nonproliferation. Directional detectors might be useful for remote detection of banned materials in the proportions necessary for a bomb. Neutrinos travel easily through the entire earth and cannot be shielded.Scientists see another, more practical, benefit for studying neutrinos. By recording the antineutrino output of nuclear reactors, detectors can discern the relative amounts of plutonium and uranium, the raw materials for making nuclear weapons. Gram for gram, fissioned plutonium and uranium have distinctive fingerprints in both the energy and rate of antineutrinos they produce, says physicist Adam Bernstein of the Lawrence Livermore National Laboratory in California. Closeup monitoring of reactors, from a distance of 10 to 500 meters, has already been demonstrated; detectors capable of monitoring weapons activity from several hundred kilometers away is possible but will require additional research and funding, Bernstein says.