Field tests using radioactive matter

Abstract

During recent years, the assessment of possible radiological consequences of a terrorist attack associated with a release of radioactive substances (RaS) has been in the focus of interest of emergency preparedness and radiation protection specialists, as well as experts dealing with the dispersion of harmful substances in the atmosphere. Suitable tools for these analyses are applications of mathematical and physical models and simulation of this attack under 'realistic' conditions. The work presented here summarises the results of four tests, in which a RaS (a Tc-99 m solution) was dispersed over a free area with the use of an industrial explosive. Detection methods and techniques employed in these tests are described and values characterising the RaS dispersion--dose rates, surface activities in horizontal and vertical directions, volume activities, their space and time distributions and mass concentrations of aerosols produced after the explosion are presented and compared. These data will be applied to a comparison of outcomes of models used for the assessment of radiation accidents as well as in future field tests carried out under conditions of more complex geometry (indoor environment, terrain obstacles, etc.).

Characterization of aerosols from RDD surrogate compounds produced by fast thermal transients

“…The first peak of the size distribution (in the nanometric size range) is generated, as explained also in [5], by the condensation of the high temperature vapour released, followed by their agglomeration. The second peak (in the micrometre size range) has been related to mechanical shock, similarly to what observed in the precedent integral experiments [6][7][8]. In the integral tests, the micrometre-size aerosols were generated by explosive blasts, while in our tests this was related to a stochastic effect generated by the thermal shock on the unmelted brittle pellet or on the produced liquid layer, due to rapid laser heating.…”

“…Fast laser heating reproduced a bimodal aerosol size distribution, as observed also in integral tests [6][7][8]. Although the fractional release between these two size ranges cannot reproduce the scenario of a real detonation, the study and comparison of these aerosols can help in understanding the phenomena taking place, and the difference between solid and vaporized phases.…”

“…The influence of other source components and environmental materials on the aerosol release from RDDs has been reported by several authors [6][7][8]. Lee and coworkers [8] studied the interaction of the explosive and soil with a simulated CsCl source and observed the formation of mixed aerosols containing both carbonaceous materials and the simulated source material, and a different ratio of Cs and Cl in the aerosols.…”

System for Automated Geoscientific Analyses (SAGA) v. 2.1.4

“…Finally, two very specific examples for the utilization of SAGA should be highlighted, which particularly indicate the wide scope of the software. Different spatial detection techniques of radioactive matter being randomly dispersed on a free area were tested for the purpose of quantifying dose rates, surface activities, mass concentrations in aerosols and their temporal and spatial distributions (Prouza et al, 2010). Most peculiarly, the morphometric investigation of chewing surfaces of animals should be emphasized, which was based on an automated analysis using specific interpolation and segmentation approaches (Czech, 2010).…”

The behaviour of parent and daughter nuclides in aerosols released in radiological dispersion events: a study of a SrTiO3 source

“…Explosion experiments have been conducted to research aerosol types and sizes . The results are used to determine the extend of the exclusion zone that should be evacuated in case of a RDD detonation and to determine the perimeters that have to be decontaminated before daily life can be resumed . Various authors report that two different aerosol morphologies are created in these events, which are the result of different formation processes.…”