High-performance gamma-spectroscopy measurements of equipment retrieved from Hanford Site high-level nuclear waste tanks

Abstract

The cleanup of high-level defense nuclear waste at the Hanford Site presents many challenges. These include removing and disposing of components from buried active waste tanks to allow new equipment insertion or hazards mitigation. This paper discusses a unique automated system that provides for retrieval, high-pressure washing, inventory measurement, and containment for disposal. Key to the inventory measurement is a three-detector high-purity germanium high-performance gamma-spectroscopy system capable of recovering data at up to 90-percent saturation (200,000 counts/s). Data recovery is based on a unique embedded electronic pulser and special software to report the inventory. Each detector has different shielding specified through simulation using the Monte Carlo computer code for N-particle transport modeling. This shielding provides performance over a dynamic range of eight orders of magnitude. This paper covers system description, calibration issues, and operation.