Improvised explosives how to understand the threat and assess the risks

Abstract

The research undertaken for this thesis has contributed to address the risk posed by dual-use industrial chemicals as improvised explosives in Improvised Explosive Devices (IEDs). The novelty of this work was the investigation of the detonation properties of Urea - Hydrogen Peroxide (UHP), an oxidiser widely used in the cosmetic and pharmaceutical industries as a solid source of hydrogen peroxide, identified as a potential emerging threat, with very limited academic literature available on its explosive properties. This research project, which includes 150 instrumented firings, was also one of the first attempts to thoroughly characterise a tertiary explosive for risk assessment purposes. The detonability of UHP at small scale was first investigated, successfully validating an experimental setup and a charge geometry that closely approached large-scale behaviour and proved suitable to study other energetics. Consistent detonation performance parameters at large and small scale were determined from complementary experimental approaches, thermochemical calculations and numerical simulations. The collected academic data were further analysed in a Counter-IED (C-IED) perspective within the scope of a limited release technical-operational threat assessment (not included in this manuscript). This work has also provided valuable insights into the non-ideality of UHP, highlighting the limitations of the available characterisation methods and modelling tools. In terms of real-world impact, the results published in this body of work provide relevant knowledge to the scientific community, complementing the rather limited available academic literature with a comprehensive characterisation of UHP detonation performance. The outcome is also of great interest for the industrial risk management and process safety. This work was equally important to understand the threat and assess the risk posed by tertiary explosives in a C-IED context and address relevant recommendations to the worldwide intelligence services and the law-enforcement agencies.