Hot cell remote nuclear scanning of tank core samples

Abstract

A Westinghouse Hanford Company (WHC)-designed remote measurement system has been constructed for gamma and beta isotopic characterization of Hanford Site high-level waste tank core sample materials in a hot cell. A small, collimated, planar CdZnTe detector is used for gamma-ray spectroscopy. Spectral resolution of 2% full-width-at-maximum at 662 kiloelectronvolts (keV) has been obtained remotely using risetime compensation and limited pulse shape discrimination (PSD). Isotopic measurement of high-energy 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 a fast, qualitative stratigraphic assessment (with isotopic information) of high-level radioactive material. Both gamma spectroscopy and beta measurements have been performed on actual core segments. Differences in radionuclide content, which correspond with color or texture variations, have been seen in constant cross section core samples, although for many samples the activity variation can be ascribed to geometry and/or mass factors. Discussion of the design, implementation, results and potential benefits will be presented