SUCCESSFUL BLIND TESTING OF NWIS FOR PITS AT LOS ALAMOS NATIONAL LABORATORY

In August 1997, the Defense Special Weapons Agency (DSWA) sponsored a series of blind tests of Nuclear Weapons Identification System (NWIS) technology on pits from dismantled nuclear weapons. Reference signatures were acquired for six different Pu weapons components in containers. On the third day, five containers were presented and declared to be pit types A, B, C, D, and E. Both active (with Cf source) and passive (no Cf source, only the inherent source from the spontaneous fission of 240Pu) NWIS measurements were performed. NWIS measurements determined that all declarations were false and that weapons component declared to be A was B, declared weapons component B was C, declared weapons component C was not a Pu weapons component, but an (a, n) neutron source, declared weapons component D was E, and declared weapons component E was D. The declarations and the identification of the parts with passive NWIS measurements were the same for active NWIS measurements. Oak Ridge was informed by DSWA that these were the correct answers. These measurements (blind testing at that) showed that NWIS is very useful for Pu weapons components in containers and thus very useful for storage verification. Previous testing at the Oak Ridge Y-12 Plant had already verified its usefulness and sensitivity for highly enriched uranium weapons components. The fact that NWIS measurements Pu components can be performed passively (no Cf source) simplifies its use for this application. This demonstrated applicability to Pu weapons components in containers shows NWIS to be a useful tool for bilateral or trilateral agreements and nuclear safeguards in general. INTRODUCTION A nuclear weapons identification system (NWIS), under development since 1