Applicability of the Curium Ratio Technique for Safeguarding at Electrochemical Recycling Process

For safeguards verification of the feed material (spent fuel), product outputs, and waste forms from the electrochemical processing, it is necessary to determine the Pu content in these items. The intense neutron emission rate from curium in the process materials makes it difficult to directly measure special nuclear materials. At the same time, however, it can be a useful signature to measure and calculate the mass of special nuclear materials, and track them throughout a process (i.e., the curium balance method). The traditional use of this technique relies heavily on an accurate and constant ratio of Pu/Cm to determine the Pu content. It is unknown whether this ratio remains constant throughout the electrochemical process, and whether the material to be assayed is homogeneous enough to apply this technique. To understand the effects by the constancy of this ratio and determine whether traditional safeguards techniques can be used, the concentration of actinides and homogeneity in the laboratory-scaled (several tens gram) process material is being analyzed. Measurement uncertainties were estimated using the simulation of neutron and gamma-ray measurement on the input of spent fuel material, product ingot, and waste forms. This paper describes the basic approach of a curium ratio technique applying an electrochemical process, and discusses the applicability based on an evaluation of the effectiveness of each process material, the measurement uncertainties, and the constancy of the Pu-to-Cm ratio.