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TAM-D - Special Session: Use of Drones to Enhance Surveys

Centennial Ballroom 300D   09:30 - 11:30

Chair(s): Shannon Thompson
TAM-D.1   09:30  A Review Of The Applications Of Drones For Radiological Surveys SW Thompson*, PNNL

Abstract: This work presents an overview and a review of the recent use of drones for radiation surveys. Drones include both user-controlled and autonomous vehicles designed to operate on land, in water, or in the air. Recent market literature on the use of aerial drones for all U.S. industries indicates that the year over year growth was over 70% between 2020 and 2021. Drone user survey respondents indicated their major goals were to collect measurements, improve visualization of areas or facilities, and improve safety. Industry-wide, the primary uses were in construction, energy, real estate, and agriculture. Like the expanding uses of drones and robots across all industries, the applications of drones and robots for radiation surveys has increased rapidly over the past few years. The drone is the vehicle with which to attach various sensors and instruments and, depending on the survey goals and scenarios, may be applied in a variety of ways. This review compiles work performed by various entities to form a summary of the current state of practice, and strategies, options, and challenges to consider. It also serves as an introduction to this special session and provides context for the reader.

TAM-D.2   10:00  UAV-Based Gamma Surveys for NORM Applications TJ Alecksen*, Environmental Restoration Group, Inc.

Abstract: Gamma survey techniques are an especially powerful decommissioning tool at naturally occurring radioactive material (NORM) sites due to both the low cost to obtain data over a large spatial scale and the abundance of gamma emitters in the uranium and thorium decay series. Gamma surveys are executed by coupling a detector – most often a sodium iodide scintillometer – to a global positioning system (GPS), then reporting a location and gross gamma reading coincidentally to a data logger. Systems may be carried by field personnel or mounted to a car or all-terrain vehicle. The resulting data set provides a high-resolution map consisting of individual measurements, each having a greater estimation uncertainty of the gamma radiation field due to the shorter counting interval. Frequently this map is also correlated to soil concentrations of NORM radionuclides (most often, Ra-226) and/or exposure rate. Gamma survey parameters such as scan speed, transect spacing, and data logging frequency define the spatial resolution of the resulting surface, and can be optimized depending on the desired survey sensitivity. Unmanned Aerial Vehicles (UAV) have become a platform for performing gamma radiation surveys due to their ability to survey in areas that are unsafe or inaccessible to personnel or vehicles. This presentation discusses some of the tradeoffs of performing UAV-based gamma surveys for NORM-based applications and discusses various UAV survey results. Results show that the use of real-time and aerial survey platforms provides a method for characterizing the spatial extent of contamination subject to sensitivity limitations governed by source size and concentration. Cost-effective reconnaissance of potential background reference areas is another useful application of UAV-based gamma surveys, particularly in rugged, inaccessible terrain. UAV survey parameters such as detector height and aerial scan speed must be carefully selected depending on the objectives of the survey. When properly conceived, UAV gamma surveys are a powerful and cost-effective tool for characterizing the spatial extent and general magnitude of terrestrial NORM contamination. However, both the advantages and limitations of this technique must be considered in a context of survey objectives.

TAM-D.3   10:30  UAV-borne spectrometry applications for geological mapping and monitoring of radioactive ecological loads (case studies) V Štěpán*, Czech Technical University in Prague, Czech Republic ; L Thinová, Czech Technical University in Prague, Czech Republic; J Klusoň, Czech Technical University in Prague, Czech Republic; J Martinčík, Czech Technical University in Prague, Czech Republic; P Otáhal, National Institute for Nuclear, Chemical and Biological Protection, Kamenná, Czech Republic

Abstract: UAV-borne gamma-ray detectors fill the gap between wide-area radiometric mapping using crewed aircraft/helicopters and surveys done on foot. They enable secure data acquisition in otherwise inaccessible places and help automate and speed up the survey. However, their application comes with constraints and challenges different from the (in Europe) traditional way of walking with a spectrometer on one's back. These will be demonstrated and discussed in the context of two case studies, both including data from aerial and ground measurements. Instrumentation for the studies included DJI M600 Pro equipped with the UgCS SkyHub terrain-following system, gamma spectrometry systems D230A with two cylindrical 2 inch x 2 inch NaI(Tl) detectors for UAV-borne measurements and GT-40 with a 3 inch x 3 inch NaI(Tl) for ground measurements (both made by Georadis s.r.o., Czech Republic) and DJI Mavic 2 Pro. Terrain models were created in Agisoft Metashape. The first case study utilises UAV for geological mapping. The survey was performed close to a former quarry near Valkerice village, Czech Republic. This site features higher concentrations of U and Th in sodalite trachyte typical, making them distinguishable from the background of quaternary sediments. Ground measurements were compared with aerial data from 3–10 m AGL. The measurements are complemented with MCNP6 Monte Carlo simulations and spectra unfolding. The second study focuses on an ecological load, Ra-226 remnants in the floodplain of Ploucnice river, linked to historical water releases from the uranium mining industry upstream. In situ and laboratory gamma spectrometry measurements were used to assess the impact of the contamination and quantify the effective dose from the human consumption chain of pasture-cow-milk and meat. Finally, the presented setup was compared with a next-gen configuration, a DJI M300 + D230A detector in several flights, to evaluate the effect of UAV technological evolution.

TAM-D.4   11:00  A Primer On Drone-Borne Radioelement Mapping S. van der Veeke*, University of Groningen; Medusa Radiometrics ; J. Limburg, Medusa Radiometrics; RL Koomans, Medusa Radiometrics

Abstract: The introduction of affordable heavy-duty unmanned aerial vehicles (UAVs or drones) has led to the possibility to do geophysical UAV-borne gamma-ray spectrometry surveys. Historically, gamma-ray spectrometry studies characterise the geological composition of an area and aid in the search for mineral resources. More recently, this technique is being used to track and identify artificial radioactive contamination or as a proxy for the soil texture, which is valuable input for agricultural applications. Technological developments in UAVs and spectrometers have resulted in the possibility of UAV-borne gamma-ray spectrometry studies. However, the survey preparation, execution, and data analysis has been recognised as significantly different from the currently used methodologies for ground-borne and “classic” airborne radioelement mapping. A standardised approach is needed to facilitate the widespread use of UAV-borne gamma-ray spectrometers. This research is a first attempt towards a set of ‘guidelines for UAV-borne radioelement mapping’, which gives a guideline that describes how a UAV borne-radiometric survey could be implemented by going over the survey implementation steps in chronological order. This implementation is based on currently existing gamma-ray spectrometry guidelines, recently published research in the field of UAV-borne gamma-ray spectrometry and experience collected in field studies. The primary purpose of this guideline is to develop a procedure that correctly predicts the true radionuclide concentration in the ground in a UAV-borne spectrometry study. A secondary benefit of such a guideline is its potential for further technological progress in automated data analysis. A guideline that specifies a standardised approach paves the way for technological development, leading to the broader use of gamma-ray spectrometers in environmental radiation monitoring, decontamination and decommissioning, and industrial radiation safety.

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