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This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

Measurement of radiological materials in defense nuclear waste stored in underground tanks at the Hanford Site is being used to indicate material distributions. Both safety assessment and future processing challenges are dependent on knowledge of the distribution, kinds, and quantities of various key components. Data from CdTe and neutron detector measurements are shown and correlated with physical sampling and laboratory results. The multiple assay approach is shown to increase the confidence about the material distributions. As a result, costs of physical sampling and destructive analyses can be controlled while not severely limiting the uncertainty of results.

A remote measurement system has been constructed for in-situ gamma and beta isotopic characterization of highly radioactive nuclear material in hostile environments, A small, collimated, planar CdZnTe detector is used for gamma-ray spectroscopy. Spectral resolution of 2 % fullwidth-at-half-maximum at 662 keV has been obtained remotely using risetime compensation and limited pulse shape discrimination (PSD) . Isotopic measurement of highenergy beta emitters was accomplished with a ruggedly made, deeply depleted, surface barrier silicon detector. The primary function of the remote nuclear screening system is to provide fast qualitative and quantitative isotopic assessment of high-level radioactive material.

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