Cf-252 Shuffler for Waste Assays and Safeguards Applications

The accurate determination of uranium and plutonium content in both nuclear waste and safeguards fields is very important. The measurement field is quite wide and often quite difficult to apply alpha spectrometry, gamma ray spectrometry or mass spectroscopy. Many nondestructive assay (NDA) techniques use neutron interrogation methods because of the high penetrability and the selective sensitivity of neutrons. The Cf-252 Shuffler is able to identify small quantities of uranium or other fissile material in large and/or dense waste drums. In this paper we report on a first Cf-252 Shuffler that uses software running in Windows XP and a Programmable Logic Controller. The system was developed at Canberra and is based on the Los Alamos National Laboratory (LANL) Cf-252 Shuffler design. The shuffler contains sixty- four 10-atm He-3 tubes configured in eight banks and two 4-atm He-3 tubes used as flux monitors. The neutron interrogation is realized using a 600 µg source. The control mechanism is a Programmable Logic Controller (PLC). Both communications with the PLC and data acquisition are performed through Canberra’s NDA 2000 software running on the Windows XP operating system. The shuffler data acquisition system uses the latest shift register electronics; the JSR-15, the JSB-96 and two Multiport II Multi-channel Analyzers. In this work we describe the system and algorithms utilized to convert the response of the system into fissile masses. Preliminary results using Uranium NBL-CRM-969 standards are presented.