It seems I’ve heard about “battlefield nukes” and “bunker-busting nukes” for some time now … at least since the run-up to the invasion of Iraq.
In a discussion on another board, someone pointed out that such nukes don’t exist. He wrote that a “nuke” is either a city-destroying device or it’s nothing.
Is this true? If so, what are talking heads talking about when the term “battlefield nukes” is trotted out?
You can make a nuke very small, and the US has or had some small nukes in its arsenal. I think that the weakest nukes might even be weaker than the biggest chemical bombs. Apparently, though, some military types consider the current designs to be inappropriate for some missions they’d like to use nukes for (I don’t know the details), so there’s some call to design new small nukes for those missions.
The US dismantled it’s last battlefield nuke in 2003.
You can do a google search for “tactical nuke”. Small nukes meant to be used more or less on a conventional battlefield were developed a long time ago but people have had a hard time coming up with good uses for them and keep the results from escalating into a full nuclear war. There has been some renewed interest in developing new ones.
Here’s a page with a picture of the W-79 warhead (scroll down).
A device that creates a 10 kiloton explosion creates a 10 kiloton explosion, regardless.
However, the packaging determines how the explosion will affect the target. Most traditional nuclear bombs are designed to explode in the air above a target to cause the most havoc on the ground beneath them. However, it is possible to place a nuclear bomb in a heavily armored casing that will cause it to penetrate the ground for several feet before exploding. This would cause less of the explosion to roll out and knock down and/or incinerate buildings at a distance from the explosion while transmitting a lot of concussive force to the earth immediately around the bomb. Such a bomb, designed to explode after penetrating the earth could be a very effective “bunker buster.” While I have not kept up on tactical nukes that much in recent years, we very definitely had several such bombs under development 30 years ago and I find it difficult to believe that we simply walked away from that knowledge.
I doubt that a nuclear device could be used in a “shaped charge” configuration (where the entire force of the explosion is directed one way rather than scattering all over), but if they could be devised, they would have a clear advantage as bunker busters. (I still doubt that they are practicable.)
Battlefield nukes were simply smaller devices intended to be fired from artillery. They were never a particularly brilliant idea (since they meant that the attacking troops needed to be heavily protected from their own weapon and scrubbed periodicially–not an easy task on the battlefield). There was a movement to scrap those.
The problem with these has usually been fallout of the political kind. Once you’ve used a 'nuke, no matter how small, you’ve pretty much accepted their use in your little skirmish, and you can expect the “other side” to retaliate in kind, even if their stockpile only comes in “extra large”. (Meaning it seems neat, but it’s kind of a useless thing to have around)
Chemical and nerve agents fall in the same category of “we won’t use them on you if you don’t use them on us” type of weapon.
It’s not really that simple. The yield of a large (10kip) bomb conventional weapon might have the same nominal yield as a 10k rated nuke, but the brisance and thermal effects are going to be substantially different than a conventional device, even ignoring the effect of ionizing radiation and radioactive fallout. Nuclear weapons, particularly thermonuclear (fusion) devices can be scaled up readily without a proportional increase in size; most of the bulk and weight of a nuke is in the accompanying hardware, not the “physics package”.
Again, there are limitations which may not be all that obviuos; penetrating more than a few tens of feet into even soft Earth with an RV moving at thousands of feet per second is a nontrivial exercize; at those speeds and pressures the ground acts like a very viscious fluid rathen than a frangible solid, and a backpressure keeps the penetrator from digging in too deeply. There is also the fact that nuclear devices are quite delicate, far moreso than conventional explosives; even a minor deformation or miselighnment, and especially a failure of a single containment charge can cause the device to fizzle or even fail to detonate entirely. Protecting the device against the shock and jerk of ground impact at hundreds of gees of deceleration and impulse in the billions of newton-seconds is unlikely, regardless of how heavy and robust the case is. A “bunker buster nuke” might be able to penetrate a bunker fifty or one hundred feet in the ground, but is unlikely to get to a vault three or four hundred feet down, or built deeply into solid granite (hence, the placement of NORAD in and under Cheyenne Mountain). You can penetrate that deep with repeated blasts (provided that your delivery vehicle is sufficiently accurate), but this is an ablative breach, not single penetration and blast.
A bunker buster would kick a whole mass of fallout into the atmosphere and the radiation would activate a lot of it, though. This would be a bad thing for anyone living in or downwind of the operational area. And as Nanoda points out, the indefinite scalability and casual destructiveness of nukes makes them essentially different than conventional weapons; if you believe that your opponent is likely to strike at you and eliminate your ability to counterstrike then it not only makes sense but is imperative that you attack first, and with overwhelming force. In theory of games jargon, there is no static or Nash equilibrium to a nuclear exchange; it can escalate indefinitely (or at least until the opponents are completely obliterated or are out of weapons). This is rarely, if ever, the case with conventional weapons; creating the same level of damage that can be done with even the smallest nuclear devices requires a massive, logistically complex, coordinated assault, not a handful of people in a plane or a single missile.
And politically, on the world stage, it would be bad for the US or our allies to use nuclear weapons in any but the most dire circumstance, as it would undercut any moral high road or ethical argument for nonproliferation. If the US is willing to wield weapons and throw its weight around, why shouldn’t North Korea, Pakistan, or Iran?
Stranger
Stranger, if you don’t know what you’re talking about, please don’t make things up.
Just kidding. Excellent post.
Especially with respect to Tom’s post, this nice little article describes just how hard it is for a low-yield nuke to penetrate the earth sufficiently for its radiation to be “trapped” there.
Sorry, I was presuming equal comparisons of nuclear weapons. (I didn’t even think we had a 10 kT conventional weapon.)
It should be noted, however, that I only mentioned that nukes could be used as bunker busters (subject to the limitations in Stranger On A Train’s post) not that such bombs would be clean.
The GBU-43/B “MOAB” (Mother of All Bombs) has an 18.7kip of H6 (a combination of RDX, TNT, and powdered aluminum). I’m not sure how that shakes out in terms of yield as opposed to 10kip of pure TNT (which is the benchmark for yield of nuclear weapons), but I’m guessing the total energy yield and brisance is favorable in comparison. The MOAB will produce a large updraft (leading to a mushroom cloud) due to local thermal effects and a substantial crater, but of course won’t develop x-rays or secondary thermal pulse from ionizing radiation, nor will it develop activating neutron radiation. I expect the area of total destruction will be similar to that of a comperable yield nuclear device, but effects outside the the that radius should be substantially less, i.e. no radiation exposure, corneal burns, secondary combustion, et cetera.
Anyone talking about “clean” or “contained” use of ground-burst nuclear weapons is speaking through their hat. Short of jacketing the bomb in cobalt, zinc, arsenic, and sodium, there is no dirtier use (in terms of residual radiation) of a nuclear weapon. It’s a pity, really, that we’ve lost the sense of horror of the effects of nuclear weapons; being nearly three generations away from the last usage has made at least some people fairly jaded in regard to a horribly destructive effects a nuclear exchange can have on noncombatants.
Stranger
A Tangent:
The M1-A1 Abrams tank is armored in depleted Uranium; apparently, an exceptionally stout material.
If the outer casing of a bunker-buster nuke were armored with depleted…or enriched…uranium, would that add to the nuke’s punch?
Years ago in Scientific American I read about an idea how to do this. You surround a big nuke with several small ones, and time the detonations so that the little ones go off just before the big one. If you time it right, the shockwaves from the small nukes will shape the blast from the big one into a jet.
Stranger, you’re talking about a 20 kip = 20,000 pound = 0.01 kiloton nuclear device (like the “Davy Crockett”) being comparable to a large conventional bomb (such as the 18,700 pound MOAB), right?
We don’t have anything like a 10 kiloton conventional weapon. I suppose a 10 kiloton non-nuclear explosion isn’t completely out of the question–you could detonate a freighter full of explosives–but it wouldn’t be very easily delivered to the target. And 10 kilotons is still definitely on the small side for strategic nuclear weapons.
Fairly sure I read a recent article in New Scientist that reported on the US abandoning its research into nuclear tipped bunker busters in favour of modifying its current conventional bunker weapons.
Its all a bit sensitive really since lots of non-nuclear countries that the UK and the US preach to in terms of non-nuclear proliferation whilst at the same time conducting further research into weapons such as depleted uranium technologies which technically (as far as im aware) fall into the category of nuclear weapons.
Kind of like saying “you cant have them but look at the shiny new nuclear weapon we just built”
The whole bunker-buster argument is specious. What they want it to do, it won’t do – make countries which have it in for us harmless.
The technology itself is killing a fly with a hammer. The function they envisage for it – destroying a secure, hardened underground facility – could be fulfilled by dropping a couple of tons of sealant on the entrance and air supply of such a base, for example. Or precision-guided fuel-air. Or posting a squad of marines. But that would involve messy ground combat entanglement, instead of feeding the fantasy of dropping and flying away happy.
Sailboat
Bolding mine. No, depleted uranium has nothing to do with nuclear weapons; it’s just a dense metal.
Scientific American has done a couple of articles on this over the years. They’ve inevitably come to the conclusion that such weapons are not feasible; there’s no way to contain the fall-out.
Links (need to subscribe to get the full articles)