Study of incompatibility of ammonium nitrate and its mechanism of decomposition by theoretical approach

Abstract : The dramatic accident involving ammonium nitrate (AN) that took place at Toulouse in September 2001 has once again focused attention to the complex hazards pertaining to this chemical. Despite the significant efforts made to increase AN safety over the whole supply chain, we are still facing insufficient knowledge of the actual mechanisms of ammonium nitrate decomposition that may take place in abnormal situations. The paper proposes a theoretical study of chemical incompatibilities of ammonium nitrate with the aim to better understand the driving mechanism(s) through which the explosive reaction takes place with the neat or contaminated substance, to identify what molecules can realistically be generated from this process and to estimate the energy involved. The results, coupled with experimental data, should allow a better understanding of ammonium nitrate hazard profile.