In this paper, we report on a system developed at Canberra based on the LANL Cf-252 Shuffler design. The shuffler contains 64 10-atm He-3 tubes configured in eight banks and 2 4-atm He-3 tubes used as flux monitors. The neutron interrogation is realized using a 600 ug 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 data acquisition uses the latest shift register electronics; the JSR-15, the JSB-96 and two Multiport II Multichannel Analyzers. In this work, we describe the algorithms utilized to convert the response of the system into fissile masses. Preliminary results using Uranium NBS standards will also be presented.