Miniaturised Low-Cost Gamma Scanning Platform for Contamination Identification, Localisation and Characterisation: A New Instrument in the Decommissioning Toolkit

Abstract

Formerly clandestine, abandoned and legacy nuclear facilities, whether associated with civil or military applications, represent a significant decommissioning challenge owing to the lack of knowledge surrounding the existence, location and types of radioactive material(s) that may be present. Consequently, mobile and highly deployable systems that are able to identify, spatially locate and compositionally assay contamination ahead of remedial actions are of vital importance. Deployment imposes constraints to dimensions resulting from small diameter access ports or pipes. Herein, we describe a prototype low-cost, miniaturised and rapidly deployable ‘cell characterisation’ gamma-ray scanning system to allow for the examination of enclosed (internal) or outdoor (external) spaces for radioactive ‘hot-spots’. The readout from the miniaturised and lead-collimated gamma-ray spectrometer, that is progressively rastered through a stepped snake motion, is combined with distance measurements derived from a single-point laser range-finder to obtain an array of measurements in order to yield a 3-dimensional point-cloud, based on a polar coordinate system—scaled for radiation intensity. Existing as a smaller and more cost-effective platform than presently available, we are able to produce a millimetre-accurate 3D volumetric rendering of a space—whether internal or external, onto which fully spectroscopic radiation intensity data can be overlain to pinpoint the exact positions at which (even low abundance) gamma-emitting materials exist.

Introductory chapter: Exploring the Multifaceted Applications of Gamma Rays in Science and Technology

“…State-of-the-art spectroscopic gamma detectors offer the highest level of accuracy in measurements. When used in conjunction with suitable modeling approaches, this technology has the capability to produce 3D contamination maps that provide estimates of material depth and activity levels [32]. Ensuring high-quality monitoring after an incident is crucial for effectively controlling health risks and providing guidance for intricate, prolonged remediation processes.…”

Digital Mock-Ups for Nuclear Decommissioning: A Survey on Existing Simulation Tools for Industry Applications

“…Surveys such as these require novel radiation detectors which are low-cost and easy to deploy. Verbelen et al [16] developed a miniaturised gamma-scanning platform for decommissioning scenarios, the 'CC-RIAS', for the purpose of environment mapping and radioactive waste characterization. The system was specifically designed to be small enough to deploy through access ports in nuclear sites and includes a commercial CZT gamma spectrometer and a motorised pan-tilt base.…”

An Introduction to Nuclear Industrial Archaeology

“…(Left) a portable NaI(Tl) gamma spectrometer of type Mirion SPIR-Ace[52] used to measure gamma radiation dose rates in excess of 1.0 mSv h −1 on the outside of a pipe connecting a mixer-settler tank in a legacy uranium ore processing facility. (Right) a collimated gamma spectrometer[53] mounted on a pan-tilt unit and suspended on a tripod to map contamination in an industrial environment[51].…”