Explosives insensitive munitions

The explosives used for military purposes are different from those used in industry. Not only thermo mechanical power for destruction, but also various other characteristics are required. Experimental tests, such as slow cook-off fast cook-off, bullet impact, and sympathetic explosion tests, must be passed to meet the requirements for insensitive munitions (IM). The aerodynamic heating of warheads on flight projectiles is also an important factor in designing warheads. 

Insensitive Munitions and Some New Insensitive Explosives/Formulations... 

A formal international requirement for insensitivity was raised as far back as 1984 by NATO s Conference of National Armament Directors (CNAD) AC/310 Partnership Group on Safety and Suitability for Service Munitions and Explosives . As a result, a pilot NATO Insensitive Munitions Information Center (NIMIC) was set-up in the USA in 1988. Subsequently, after a couple of years when technologies for production of most ammunition of insensitive types were available and implementation and fielding was more important, the name NIMIC was changed to NATO s Munitions Safety Information Analysis Center (MSIAC) in December 2004. The advantages derived as a result of implementation of IM Policy are briefly described in Chapter 6 (Section 6.8). 

A new insensitive, cast-cured PBX called -135, has been developed in order to meet the requirements of US Navy s Insensitive Munitions Advanced Development Programfor High Explosives (IMAD/HE). PBXIH-135 has enhanced internal blast performance, improved non-vulnerability and penetration survivability characteristics compared with PBXN-109. Thermobaric explosives are required to defeat hard and deeply buried structures. PBXIH-135 thermobaric explosive which not only offers effective blast and thermal effects, but is also extremely insensitive to factors responsible for accidental detonation during transit or storage, may also be used for this purpose. 

Recent developments of novel explosive materials have concentrated on reducing the sensitivity of the explosive materials to accidental initiation by shock, impact and thermal effects. The explosive materials, which have this reduced sensitivity, are call Insensitive Munitions, (IM). Although these explosive materials are insensitive to accidental initiation they still perform very well when suitably initiated. Examples of some explosive molecules under development are presented in Table 1.5. A summary of the significant discoveries in the history of explosives throughout the world is presented in Table 1.6. 

This book outlines the basic principles needed to understand the mechanism of explosions by chemical explosives. The history, theory and chemical types of explosives are introduced, providing the reader with information on the physical parameters of primary and secondary explosives. Thermodynamics, enthalpy, free energy and gas equations are covered together with examples of calculations, leading to the power and temperature of explosions. A very brief introduction to propellants and pyrotechnics is given, more information on these types of explosives should be found from other sources. This second edition introduces the subject of Insensitive Munitions (IM) and the concept of explosive waste recovery. Developments in explosive crystals and formulations have also been updated. This book is aimed primarily at A level students and new graduates who have not previously studied explosive materials, but it should prove useful to others as well. I hope that the more experienced chemist in the explosives industry looking for concise information on the subject will also find this book useful. 

This term describes improved properties of energetic materials. In the 1990s it was shown that with careful recrystallization techniques the sensitivity RDX can be reduced on a crystalline level. Nowadays, reduced sensitivity variants of RDX, assigned as RS-RDX or l-RDX (for insensitive), are provided by different manufacturer and tested, particularly in plastic bonded explosives PBXfor Insensitive Munitions IM. Besides, RS-variants of HMX and other high explosives, and characterization and quality assessment techniques for Reduced Sensitivity are in the scope of actual research. 

Trinitrophenol (4), commonly known as picric acid (VOD 7350 m/s, d = 1.71 g/cm ), was once used as a military explosive although its highly acidic nature enables it to readily corrode metals. This kind of reaction has led to many fatal accidents, a consequence of some metal picrates being very sensitive primary explosives. The lead salt of picric acid is a dangerous explosive and should be avoided at all cost. In contrast, the ammonium (Explosive D, VOD 7050 m/s, d = 1.60 g/cm ) and guanidine salts of picric acid are unusually insensitive to impact and have been used in armour piercing munitions. 

Military explosives comprise explosives and explosive compositions or formulations that are used in military munitions (bombs, shells, torpedoes, grenades, missile or rocket warheads). The bulk charges (secondary explosives) in these munitions are insensitive to some extent and are, therefore, safe for handling, storage and transportation. They are set off by means of an explosive train consisting of an initiator followed by intermediates or boosters. 

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