# What is the smallest nuclear weapon that can be made **URL:** \ **Category:** Factual Questions\ **Created:** [April 24, 2012, 2:48am UTC](https://boards.straightdope.com/t/what-is-the-smallest-nuclear-weapon-that-can-be-made/619771 "2012-04-24T02:48:44Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [April 24, 2012, 2:48am UTC](https://boards.straightdope.com/t/what-is-the-smallest-nuclear-weapon-that-can-be-made/619771/1 "2012-04-24T02:48:44Z")
If you wanted to make the smallest nuclear weapon possible (whether fission or fusion, although I’m guessing fusion would require something far bigger), what is the physically smallest it could be and still function? I don’t know enough about physics to know how much force the gun or implosion designs have to have in order to detonate the bomb. Can you make something with a 3 foot long barrel and make a gun type design, or are explosives powerful enough to trigger a nuclear explosion in something that small non-existent? I’ve heard the USSR and US built nuclear weapons about the size of small refrigerators, but suitcase nukes were never verified. I don’t know if they were invented but if they were it isn’t like the US and USSR would admit to making them anyway. ---
**Author:** ![Magiver](https://avatars.discourse-cdn.com/v4/letter/m/4491bb/32.png) [@Magiver](https://boards.straightdope.com/u/Magiver)\ **Post date:** [April 24, 2012, 2:58am UTC](https://boards.straightdope.com/t/what-is-the-smallest-nuclear-weapon-that-can-be-made/619771/2 "2012-04-24T02:58:55Z")
[Davy Crockett](http://en.wikipedia.org/wiki/Davy_Crockett_%28nuclear_device%29) comes to mind. The M-388 round used a version of the W54 warhead, a very small sub-kiloton fission device. The Mk-54 weighed about 51 lb (23 kg), with a yield equivalent to somewhere between 10 or 20 tons of TNT — very close to the minimum practical size and yield for a fission warhead. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [April 24, 2012, 3:51am UTC](https://boards.straightdope.com/t/what-is-the-smallest-nuclear-weapon-that-can-be-made/619771/3 "2012-04-24T03:51:34Z")
The Davy Crockett is probably near the limit for a uranium or plutonium-based device, but you could in principle get much smaller with other, more exotic, isotopes. IIRC, you could make a nuclear hand grenade using americium (or maybe it was californium). ---
**Author:** ![wheresmymind](https://avatars.discourse-cdn.com/v4/letter/w/91b2a8/32.png) [@wheresmymind](https://boards.straightdope.com/u/wheresmymind)\ **Post date:** [April 24, 2012, 4:20am UTC](https://boards.straightdope.com/t/what-is-the-smallest-nuclear-weapon-that-can-be-made/619771/4 "2012-04-24T04:20:57Z")
The [W80](http://en.wikipedia.org/wiki/W80_%28nuclear_warhead%29) is a cylinder about 1 foot in diameter and 2.5 feet long, yield up to 150 kt. The [W87](http://en.wikipedia.org/wiki/W87) and [W88](http://en.wikipedia.org/wiki/W88) warheads fit inside cones less than 2 feet in diameter and 6 feet tall, with yields approaching 500 kt. So you can build “full-sized” (10-20 times more powerful than the Hiroshima/Nagasaki bombs, able to destroy city-sized targets) thermonuclear warheads much smaller than refrigerators. They weigh hundreds of pounds however, so you’d need at least a dolly (or maybe a forklift) to transport them. Keep in mind that these are fusion bombs, which basically have a fission bomb as their primary. I agree that the W54 is probably about as small as you’ll be able to get a nuclear warhead. In the Wiki article linked above it’s noted that they required extensive testing (more so than any warhead before them) to make them reliable. Any smaller and you’d be better off using conventional explosives for their predictability alone. ---
**Author:** ![Declan](https://avatars.discourse-cdn.com/v4/letter/d/ecae2f/32.png) [@Declan](https://boards.straightdope.com/u/Declan)\ **Post date:** [April 24, 2012, 6:34am UTC](https://boards.straightdope.com/t/what-is-the-smallest-nuclear-weapon-that-can-be-made/619771/5 "2012-04-24T06:34:59Z")
> [@Wesley\_Clark](#): > > If you wanted to make the smallest nuclear weapon possible (whether fission or fusion, although I’m guessing fusion would require something far bigger), what is the physically smallest it could be and still function? > > I don’t know enough about physics to know how much force the gun or implosion designs have to have in order to detonate the bomb. > > Can you make something with a 3 foot long barrel and make a gun type design, or are explosives powerful enough to trigger a nuclear explosion in something that small non-existent? > > I’ve heard the USSR and US built nuclear weapons about the size of small refrigerators, but suitcase nukes were never verified. I don’t know if they were invented but if they were it isn’t like the US and USSR would admit to making them anyway. I think the smallest nuke was an air to air missile, like either the Genie or the Falcon. I heard the suit case nuke was a poor translation, the russians meant something that looked like a steamer trunk, which read suit case in english. It also occurs to me that the SADARM was carried by 10th special forces personal on their back, but it would be around .5kt or so. Declan ---
**Author:** ![Dave.B](https://avatars.discourse-cdn.com/v4/letter/d/9f8e36/32.png) [@Dave.B](https://boards.straightdope.com/u/Dave.B)\ **Post date:** [April 24, 2012, 12:25pm UTC](https://boards.straightdope.com/t/what-is-the-smallest-nuclear-weapon-that-can-be-made/619771/6 "2012-04-24T12:25:17Z")
> [@Chronos](#): > > IIRC, you could make a nuclear hand grenade using americium (or maybe it was californium). Would it be humanly possible to throw it far enough to avoid being injured or killed by it? ---
**Author:** ![smithsb](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/smithsb/32/12107_2.png) [@smithsb](https://boards.straightdope.com/u/smithsb)\ **Post date:** [April 24, 2012, 1:46pm UTC](https://boards.straightdope.com/t/what-is-the-smallest-nuclear-weapon-that-can-be-made/619771/7 "2012-04-24T13:46:57Z")
Suitcase nuke; for the US it was called the SADM (Special Atomic Demolition Munition). Modified W54. Davy Crockett, Falcon AIM-26A missile, and the SADM. Not really a “suitcase” but a big backpack. The W48 155mm artillery shell was around half the diameter for the nuke package compared to the W54 in the Davy Crockett (\<6’ vs. 11’). See the Wiki for the W54 and and W48 munitions. Note that a design capable of fitting in a 105mm artillery shell was considered possible. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [April 24, 2012, 1:59pm UTC](https://boards.straightdope.com/t/what-is-the-smallest-nuclear-weapon-that-can-be-made/619771/8 "2012-04-24T13:59:59Z")
There isn’t a sharp demarcation line for how small a nuke can be; rather you get a dropoff curve for the yield as the weight of the package decreases and the efficiency of the reaction drops. It becomes a matter of how small a “fizzle” you consider a nuclear explosion. The Davy Crockett was really sort of intermediary between a tactical nuke and a “dirty bomb”; it fizzled just enough to produce a deadly pulse of immediate radiation and scatter radioisotopes across it’s target area. ---
**Author:** ![hotflungwok](https://avatars.discourse-cdn.com/v4/letter/h/edb3f5/32.png) [@hotflungwok](https://boards.straightdope.com/u/hotflungwok)\ **Post date:** [April 24, 2012, 2:08pm UTC](https://boards.straightdope.com/t/what-is-the-smallest-nuclear-weapon-that-can-be-made/619771/9 "2012-04-24T14:08:34Z")
> [@Chronos](#): > > IIRC, you could make a nuclear hand grenade using americium (or maybe it was californium). I read about a theoretical weapon made for sniper rifles using californium. Californium (it said) has a very low critical mass, and it was suggested that you could make a bullet with two pieces of it in the tip, separated by something that absorbs neutrons. The barrier is destroyed on impact, and the shape of the bullet forces the two pieces of californium together. ---
**Author:** ![MEBuckner](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mebuckner/32/2896_2.png) [@MEBuckner](https://boards.straightdope.com/u/MEBuckner)\ **Post date:** [April 24, 2012, 3:38pm UTC](https://boards.straightdope.com/t/what-is-the-smallest-nuclear-weapon-that-can-be-made/619771/10 "2012-04-24T15:38:13Z")
> [@Chronos](#): > > IIRC, you could make a nuclear hand grenade using americium (or maybe it was californium). > [@Dave.B](#): > > Would it be humanly possible to throw it far enough to avoid being injured or killed by it? “Their weaponry still has a good reputation, as long as you know what you’re buying. Stay away from the sale on neutron hand grenades.” “Heh. For those with strong throwing arms. Fear not, neutron hand grenades aren’t on the list.” (From Lois McMaster Bujold’s Miles Vorkosigan story “Labyrinth”.) ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [April 24, 2012, 4:49pm UTC](https://boards.straightdope.com/t/what-is-the-smallest-nuclear-weapon-that-can-be-made/619771/11 "2012-04-24T16:49:36Z")
> [@Dave.B](#): > > Would it be humanly possible to throw it far enough to avoid being injured or killed by it? “Private Clark Kent, I have a very special assignment for you…” ---
**Author:** ![Christopher\_Robin\_Davies](https://avatars.discourse-cdn.com/v4/letter/c/8dc957/32.png) [@Christopher\_Robin\_Davies](https://boards.straightdope.com/u/Christopher_Robin_Davies)\ **Post date:** [April 24, 2012, 4:52pm UTC](https://boards.straightdope.com/t/what-is-the-smallest-nuclear-weapon-that-can-be-made/619771/12 "2012-04-24T16:52:31Z")
> [@Elendil\_s\_Heir](#): > > “Private Clark Kent, I have a very special assignment for you…” If you have Clark Kent in your army, why do you need a nuke? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [April 24, 2012, 5:04pm UTC](https://boards.straightdope.com/t/what-is-the-smallest-nuclear-weapon-that-can-be-made/619771/13 "2012-04-24T17:04:55Z")
> [@](#): > > Would it be humanly possible to throw it far enough to avoid being injured or killed by it? Maybe, if you had a good solid rock ridge in exactly the right place. Or if you were wearing mobile infantry powered armor. Of course, any army with the tech to make such a thing would also have the tech for some suitable launcher.