# Thorium bomb **URL:** \ **Category:** Factual Questions\ **Created:** [October 3, 2023, 4:36am UTC](https://boards.straightdope.com/t/thorium-bomb/991037 "2023-10-03T04:36:06Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![EnolaStraight](https://avatars.discourse-cdn.com/v4/letter/e/41988e/32.png) [@EnolaStraight](https://boards.straightdope.com/u/EnolaStraight)\ **Post date:** [October 3, 2023, 4:36am UTC](https://boards.straightdope.com/t/thorium-bomb/991037/1 "2023-10-03T04:36:06Z")
Can a nuclear bomb be made with some amount of thorium? I understand that, although thorium itself is not fissionable, it can absorb neutrons and transmute into Uranium 233, which is fissionable. So, can a bomb be made out of thorium/ uranium 233? …no, I don’t need the answer fast…yes I appreciate the irony of my screenname in regards to this thread. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [October 3, 2023, 5:06am UTC](https://boards.straightdope.com/t/thorium-bomb/991037/2 "2023-10-03T05:06:17Z")
It takes an atomic bomb about [one microsecond](https://www.atomicarchive.com/science/fission/time-of-reaction.html) (millionth of a second) to do its thing. I suspect that is waaaay too fast to allow thorium to transmute into uranium-233 and then allow that to fission as a chain reaction. IANANuclearPhysicist. ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [October 3, 2023, 6:49am UTC](https://boards.straightdope.com/t/thorium-bomb/991037/3 "2023-10-03T06:49:22Z")
According to Wikipedia a thorium tamper does work. The lower speed of operation just requires it to be thicker. > **[Tamper (nuclear weapon)](https://en.m.wikipedia.org/wiki/Tamper_(nuclear_weapon))** > > A tamper is an optional layer of dense material surrounding the fissile material. It is used in nuclear weapon design to reduce the critical mass of a nuclear weapon and to delay the expansion of the reacting material through its inertia. Due to its inertia it delays the thermal expansion of the fissioning fuel mass, keeping it supercritical longer. Often the same layer serves both as tamper and as neutron reflector. The weapon disintegrates as the reaction proceeds and this stops the reactio... ---
**Author:** ![xtenkfarpl](https://avatars.discourse-cdn.com/v4/letter/x/c2a13f/32.png) [@xtenkfarpl](https://boards.straightdope.com/u/xtenkfarpl)\ **Post date:** [October 3, 2023, 3:18pm UTC](https://boards.straightdope.com/t/thorium-bomb/991037/4 "2023-10-03T15:18:03Z")
One could obviously breed, separate, and accumulate U233 and use that to build a bomb. According to Wikipedia, some experiments have been done with U233 as a bomb material, though it is not clear if a pure U233 bomb has ever been tested. A matter of semantics whether you would call that a Thorium bomb, though? ---
**Author:** ![gnoitall](https://avatars.discourse-cdn.com/v4/letter/g/bb73d2/32.png) [@gnoitall](https://boards.straightdope.com/u/gnoitall)\ **Post date:** [October 3, 2023, 3:48pm UTC](https://boards.straightdope.com/t/thorium-bomb/991037/5 "2023-10-03T15:48:13Z")
> [@xtenkfarpl](#): > > A matter of semantics whether you would call that a Thorium bomb, though? No, it would be a Uranium bomb. Even if the 233U was bred from Thorium feedstock. Otherwise a Plutonium fission weapon would also be called a Uranium bomb, since its fissile material is also bred from a Uranium mother. ---
**Author:** ![xtenkfarpl](https://avatars.discourse-cdn.com/v4/letter/x/c2a13f/32.png) [@xtenkfarpl](https://boards.straightdope.com/u/xtenkfarpl)\ **Post date:** [October 3, 2023, 4:02pm UTC](https://boards.straightdope.com/t/thorium-bomb/991037/6 "2023-10-03T16:02:34Z")
By most reasonable interpretations, one would have to agree. To create an actual Thorium bomb, you would need to tweak some constants of the universe so that Thorium itself is fissionable. Paging Q from Star Trek…? It would probably need just a tiny nudge to the strong or electromagnetic force… 😉 ---
**Author:** ![Folly](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/folly/32/3219_2.png) [@Folly](https://boards.straightdope.com/u/Folly)\ **Post date:** [October 3, 2023, 4:48pm UTC](https://boards.straightdope.com/t/thorium-bomb/991037/7 "2023-10-03T16:48:38Z")
> [@xtenkfarpl](#): > > It would probably need just a tiny nudge to the strong or electromagnetic force… 😉 Just a tiny…bit… more…Oops! Everything is fissile now… ---
**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\ **Post date:** [October 3, 2023, 5:02pm UTC](https://boards.straightdope.com/t/thorium-bomb/991037/8 "2023-10-03T17:02:08Z")
> [@Whack-a-Mole](#): > > I suspect that is waaaay too fast to allow thorium to transmute into uranium-233 Your suspicion is correct. Breeding of U-233 from Th-232 is a slow process. First the thorium has to absorb a neutron to become Th-233. Thorium-233 is fissile, meaning it likes to absorb slow themal neutrons, not the fast ones you get in a nuclear bomb explosion. Once it has absorbed the neutron it spontaneously decays twice before it become U-233: first from Th-233 to Pa-233 (half life of around 20 minutes) then from Pa-233 to U-233 (half life of almost a month). There’s a reason that slow breeder reactors are called that, because slow is the only way you can breed U-233. ---
**Author:** ![xtenkfarpl](https://avatars.discourse-cdn.com/v4/letter/x/c2a13f/32.png) [@xtenkfarpl](https://boards.straightdope.com/u/xtenkfarpl)\ **Post date:** [October 3, 2023, 5:16pm UTC](https://boards.straightdope.com/t/thorium-bomb/991037/9 "2023-10-03T17:16:56Z")
> [@Folly](#): > > > [@xtenkfarpl](#): > > > > It would probably need just a tiny nudge to the strong or electromagnetic force… 😉 > > Just a tiny…bit… more…Oops! Everything is fissile now… Or apparently if the strong force was just a bit stronger, the diproton would be stable. So probably no elements or periodic table at all? Well, as e e cummings put it “listen: there’s a hell of a good universe next door; let’s go” ---
**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\ **Post date:** [October 3, 2023, 5:21pm UTC](https://boards.straightdope.com/t/thorium-bomb/991037/10 "2023-10-03T17:21:16Z")
> [@bibliophage](#): > > Thorium-233 is fissile Need more coffee and I missed the edit window. I meant Th-232 is fertile by absorption of slow neutrons. ---
**Author:** ![gnoitall](https://avatars.discourse-cdn.com/v4/letter/g/bb73d2/32.png) [@gnoitall](https://boards.straightdope.com/u/gnoitall)\ **Post date:** [October 3, 2023, 9:06pm UTC](https://boards.straightdope.com/t/thorium-bomb/991037/11 "2023-10-03T21:06:51Z")
> [@xtenkfarpl](#): > > the diproton would be stable. > So probably no elements or periodic table at all? Helium-2 is technically an element. But if it were possible it might be the only element, so it would be a very short periodic table. ---
**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:** [October 3, 2023, 10:23pm UTC](https://boards.straightdope.com/t/thorium-bomb/991037/12 "2023-10-03T22:23:15Z")
If He-2 were stable, why would that imply that nothing else would be? ---
**Author:** ![gnoitall](https://avatars.discourse-cdn.com/v4/letter/g/bb73d2/32.png) [@gnoitall](https://boards.straightdope.com/u/gnoitall)\ **Post date:** [October 3, 2023, 10:27pm UTC](https://boards.straightdope.com/t/thorium-bomb/991037/13 "2023-10-03T22:27:23Z")
I was joking. I’m not a physicist or a chemist. It’s just a cute conceit, a universe full of nothing but hydrogen and diproton. ---
**Author:** ![EnolaStraight](https://avatars.discourse-cdn.com/v4/letter/e/41988e/32.png) [@EnolaStraight](https://boards.straightdope.com/u/EnolaStraight)\ **Post date:** [October 4, 2023, 3:03am UTC](https://boards.straightdope.com/t/thorium-bomb/991037/14 "2023-10-04T03:03:23Z")
“Slow neutrons.” So…surrounding a Neutron Bomb with an outer layer of thorium wouldn’t boost the yield any. The thorium would just vaporize before any transmutation occurred. ---
**Author:** ![gnoitall](https://avatars.discourse-cdn.com/v4/letter/g/bb73d2/32.png) [@gnoitall](https://boards.straightdope.com/u/gnoitall)\ **Post date:** [October 4, 2023, 3:25am UTC](https://boards.straightdope.com/t/thorium-bomb/991037/15 "2023-10-04T03:25:12Z")
True. As a tamper, it would exist long enough for its mass to provide decent inertial confinement to the primary detonation, but not long enough for the dual beta decay to finish to provide further fissile fuel in an organized fashion. Unlike a 238U tamper, which can be directly driven to usable fission by the neutron or gamma flux of the primary. The Fat Man device was estimated to have gotten 30% of its yield from the natural uranium tamper contribution. ---
**Author:** ![xtenkfarpl](https://avatars.discourse-cdn.com/v4/letter/x/c2a13f/32.png) [@xtenkfarpl](https://boards.straightdope.com/u/xtenkfarpl)\ **Post date:** [October 4, 2023, 3:49pm UTC](https://boards.straightdope.com/t/thorium-bomb/991037/16 "2023-10-04T15:49:43Z")
> [@Chronos](#): > > If He-2 were stable, why would that imply that nothing else would be? I guess there is no logical reason to suppose that. I seem to recall reading it somewhere, but can’t remember the source now, so no idea how authoritative it might have been. A stable diproton would surely have some major implications for nucleosynthesis pathways, though? I would not even try to speculate on the details. Any real nuclear physicists in the house? ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [October 5, 2023, 1:18am UTC](https://boards.straightdope.com/t/thorium-bomb/991037/17 "2023-10-05T01:18:09Z")
> [@xtenkfarpl](#): > > A stable diproton would surely have some major implications for nucleosynthesis pathways, though? I would have guessed that if it were stable just about everything else would be too. That would have pretty wide reaching implications about the nature of the universe. It would sure be a very different place. The Big Bang would likely have directly created most of the elements in significant quantities. Stars might not even form in the manner we see, and nuclear processes would have very different energies. Nucleuogenises would certainly be very different. ---
**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:** [October 5, 2023, 1:51am UTC](https://boards.straightdope.com/t/thorium-bomb/991037/18 "2023-10-05T01:51:47Z")
Really, to make the diproton stable, you’d need to completely change the nature of the Strong Force. It’s not just “make the Strong Force stronger than the electromagnetic, so they stick together”: Remember, the dineutron also doesn’t hold together, and it’s the Strong Force that blows it apart. And would do the same thing to a diproton. Meanwhile, He-3 is stable, but H-3 isn’t. ---
**Author:** ![EnolaStraight](https://avatars.discourse-cdn.com/v4/letter/e/41988e/32.png) [@EnolaStraight](https://boards.straightdope.com/u/EnolaStraight)\ **Post date:** [October 5, 2023, 2:07am UTC](https://boards.straightdope.com/t/thorium-bomb/991037/19 "2023-10-05T02:07:03Z")
A tangent: He 2 is “regular” helium with 2 protons and 2 neutrons, right? He 3 has an extra neutron. I take it a 2 proton **one** neutron nucleus cannot be a thing. ---
**Author:** ![Babale](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/babale/32/15666_2.png) [@Babale](https://boards.straightdope.com/u/Babale)\ **Post date:** [October 5, 2023, 2:45am UTC](https://boards.straightdope.com/t/thorium-bomb/991037/20 "2023-10-05T02:45:44Z")
> [@xtenkfarpl](#): > > Well, as e e cummings put it “listen: there’s a hell of a good universe next door; let’s go” In and out, 20 minute adventure [Next page](https://boards.straightdope.com/t/thorium-bomb/991037.md?page=2)