Detonation Simulant of TATP as Donor Charge of Tertiary Explosives

explosives chemistry

13 February 2024 13h30-14h30

by Mr. Djamal Belmehdi

Dual-use substances or those used to synthesize known homemade explosives (HME) are strictly controlled. Nevertheless, tertiary explosives are generally not considered as explosives by international regulations. As they are exceptionally difficult to detonate due to their low shock sensitivity and their strong non-ideal character. Their availability makes them a matter of great concern to counter-terrorism actors, particularly if used in conjunction with a relatively small charge of HME as a booster charge. By this relatively easy means, the destructive effect of a relatively small charge of HME can be multiplied by several orders of magnitude. It is however difficult to assess this issue because the detonation properties of the donor charge and the shock sensitivity of the acceptor charge are mostly not documented which most of the studies on HMEs were limited only to synthesis, sensitivity, and performances, but also because the non-ideal character and the low shock sensitivity of the tertiary explosives imply the use of very large donor and acceptor charges. In addition to the very high sensitivity of most HMEs, the synthesis, shaping and safe handling of kilogram-scale HME charges is extremely complex. To circumvent these challenges, this work aims to develop simulation booster charges composed of diluted secondary explosives with detonation properties closely resembling those of the HMEs under consideration, such as triacetone triperoxide (TATP), while maintaining the sensitivities of secondary explosives. First, we investigated the detonation properties of TATP as donor charges in a detonation train. We developed a teleoperated pneumatic system to safely and reproducibly shape TATP charges at realistic densities, utilizing confined charges to approach infinite-diameter properties closely. The detonation pressure and shock adiabate of the detonation products were experimentally determined based on measured attenuated shock velocity in inert acceptors, and the experimental detonation products' isentrope was derived from cylinder expansion test results. These experimental findings were then compared to thermodynamic code calculations to assess the non-ideal behavior of TATP charges at 0.4 g/cm3. In this webinar, the detonation properties of TATP as donor charge will be illustrated, followed by a comparative characterization of proposed simulants aimed at replicating the detonation properties of TATP, specifically at a loose density of 0.5 g/cm³, to establish safety margins. Various candidates were initially proposed and investigated. UHP at 0.61 g/cm³ demonstrated satisfactory agreement in both the reflected Hugoniot of the detonation gases and the isentrope of the detonation products. This observation positions UHP as a promising simulant for TATP. The implications of this comprehensive study extend to the potential use of these simulants as effective detonation surrogates for homemade explosives (HMEs), particularly when employed as booster charges for tertiary explosives.

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