Electromagnetic coil (EM coil) measurement technique to verify presence of metal/absence of oxide attribute

This paper summarizes how an Electromagnetic coil (EM coil) measurement technique can be used to discriminate between plutonium metal, plutonium oxide, and mixtures of these two materials inside sealed storage containers. Measurement results are from a variety of metals and Aluminium oxide in two different container types, the carbon steel AL-R8 and the stainless steel AT-400R. Within these container types two scenarios have been explored. 1.) The same configuration made from different metals for demonstrating material property effects. 2.) The same metal configured differently to demonstrate how mass distribution affects the EM signature. This non-radiation measurement method offers verification of the 'presence of metal/absence of oxide' attribute in less than a minute. In January 2001, researches at Pacific Northwest Laboratory showed this method to discriminate between aluminium and aluminium oxide placed inside an AT-400R (a total wall thickness of over 2.5 cm) storage container. Subsequent experimental and theoretical investigations into adapting the EM coil technique for arms control applications, suggests a similar response for plutonium and plutonium oxide. This conclusion is consistent with the fact that all metals are electrically conductive while most oxides are electrical insulators (non-conductors). (author)