SUMMARY
The feasibility and role of the Hybrid K-Edge Densitometer (HKED) for pyroprocessing safeguards measurements has not yet been established, and several technological and practical challenges need to be addressed. Transition to using the HKED will depend on simulations that could assist in the extension of this assay method to predict the detector response to the new sample types and configurations. The limited availability of representative solution standards expected from pyroprocessing molten salts have spurred efforts to develop a Monte Carlo model to facilitate algorithm development and optimization of the measurement configuration of the HKED system. The model will incorporate detailed geometrical dimensions of the HKED, realistic detector response tallies, optimum computational efficiency, and optimization capabilities. To ensure the fidelity of the MCNP model, the model was validated against experimental data of representative samples from traditional sample solutions. The proposed work provides the ability to examine the impact of actinide concentrations and ratios encountered with pyroprocessing sampling and to assess the impact on the measurement from non-standard sample matrices and non-homogeneities. Capabilities and limitations are discussed herein for extending the HKED system beyond solutions for aqueous systems with uranium and plutonium ratios of 100:1 to include salt based samples from pyroprocessing where uranium and plutonium ratios approach 1:1.