Dr. David Hooper, R&D Staff Member Nuclear Security Modeling Group Oak Ridge National Laboratory   Abstract The nuclear industry has a phenomenal overall track record of preventing dangerous releases of radioactive material to the atmosphere.  Sometimes, however, such releases do occur.  Notable examples include reactor accidents such as Chernobyl and Fukushima Daiichi, or the historical atmospheric testing of nuclear weapons conducted prior to the Partial Test Ban Treaty.  To evaluate risks of potential or real radioactive releases to public health…