Insensitive munitions
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Insensitive munitions are munitions which reliably fulfil their performance, readiness and operational requirements on demand, but which minimise the probability of inadvertent initiation and severity of subsequent collateral damage to weapons platforms, logistic systems and personnel when subjected to unintentional stimuli.
More simply, IM are munitions which:
- Burn when subjected to fast or slow heating, bullet or fragment attack
- Do not detonate when subjected to shape charge jet impact or when another munition detonates in a stack
The term insensitive munitions is applied to warheads, bombs, rocket motors, and similar items, but different nations and armed forces may have different standards for what constitutes an "insensitive" munition.
Navies have been concerned over the vulnerability caused by weapons magazines in the tight spaces aboard ships. A number of famous ships have been lost to shipboard munitions explosions, among them the USS Maine (ACR-1).
However, the issue of insensitive munitions is not isolated to the navies, and not even to military applications. A number of improvements have come from commercial explosives used in mining, demotion, and other applications.
A number of means have been employed to make high energy devices less sensitive to fire, shock, impact from bullets and fragments, and from explosions. Generally, most of the techniques fall into three categories.
First, the high energy device can be protected and transported with an external protection of some kind. The United States Navy buys some munitions with an external thermal barrier, for example. Some shipping containers are designed to provide a degree of protection.
Second, the chemistry of the high energy fill is chosen to provide a degree of protection. A number of plastic bound explosives are useful in this regard.
Third, the casing of the high energy device can be designed in such a way as to allow venting or some other form of pressure relief in fires.
[edit] Insensitive high explosives
Insensitive munitions are almost always filled with fire resistant, shock resistant insensitive high explosives (IHE) such as TATB or various insensitive explosive mixtures or polymer or plastic bonded explosives.
TATB particularly will not detonate if impacted by typical fragments or burned in a fire.
[edit] Nuclear weapons
Modern American nuclear weapons, and at least those of the United Kingdom, are manufactured exclusively using only insensitive munition designs, particularly the use of insensitive high explosives. These are almost exclusively TATB plastic bonded explosive (LX-17-0 and PBX-9502).
