Oak Ridge National Laboratory is making a significant contribution to the suite of nuclear security technologies available for controlling the nuclear threat. These technologies include: engineering design and testing of security systems for monitoring and control of stored nuclear materials that could be used for creation of nuclear weapons of mass destruction; advanced radiation detectors based on new materials, advanced electronics, and modern signal processing; advanced nuclear material detection systems based on active interrogation and on passive measurements; development of internationally accepted standards for radiation detection; operational testing and evaluation of nuclear smuggling countermeasures systems; advanced mass spectroscopy systems for characterization of materials associated with proliferation; modeling and simulation of likely proliferant processes; and determination of signatures of likely proliferant processes.