Nuclear weapons identification system

A nuclear weapons identification system (NWIS) has been under development at the Oak Ridge Y-12 plant since 1984. NWIS employs active neutron interrogation to obtain a variety of time and frequency analysis signature to identify nuclear weapons in containers. Advantages of NWIS are: (1) high sensitivity {small changes in configurations produce large changes in signatures}; (2) insensitivity of some signatures to background radiation, {useful for storage configurations or for tracking of secondaries through the first stage of dismantlement since the presence of the primary on the assembled system does not affect some signatures for the secondary}; (3) nonintrusive {does not reveal design information, which makes it useful for bilateral treaties or by the International Atomic Energy Agency (IAEA)}; and (4) very difficult to deceive