Why can't nuclear reactions burn the atmosphere

In summary: Basically, the US didn't believe that the atmosphere could be affected by nuclear reactions, and the physicists disproved that claim.
  • #1
Trollfaz
137
14
When the US first developed nuclear weapons against the Nazis and Japan, their primary concern was whether the nuclear reactions can trigger the atmospheric nitrogen to fuse and burn the whole atmosphere.
However this claim was instantly debunked by physicists. Their reasoning is that in order to fuse nitrogen, one needs extreme temperature (100MK) and extreme pressure such as in the center of massive stars( >3SM). The extreme conditions needs to be upheld constantly and is achieved when the intense mass of the star crushes in on it's center.
But for Earth's case, even if we do manage to fuse a few nitrogen atoms, the heat released will immediately radiate away while the pressure will swiftly disperse and prevent further extensive chain reaction. Is that the explanation?
 
Physics news on Phys.org
  • #2
Trollfaz said:
Is that the explanation?
Pretty much, yes.

their primary concern was…
That’s way too strong a statement. There were plenty of other concerns that ranked ahead of that one.
 
  • Like
Likes ohwilleke, Demystifier, vanhees71 and 3 others
  • #3
Trollfaz said:
However this claim was instantly debunked by physicists. Their reasoning is that in order to fuse nitrogen, one needs extreme temperature (100MK) and extreme pressure such as in the center of massive stars( >3SM). The extreme conditions needs to be upheld constantly and is achieved when the intense mass of the star crushes in on it's center.
There were two camps, one that the atmosphere would experience a 'fusion chain reaction' and the other would not. Some were concerned until the Trinity test, where it didn't happen.

The atmosphere density is too low, and the high temperatures in the core of a nuclear weapon dissipates very rapidly. It wouldn't be N-N fusion, because that would take much greater temperature and pressures, and CNO-cycle only happens in stars with the right density (and pressures) and composition (age). The pressure maintains the density at temperature (and there is quasi-steady-state balance between radiation (force) pressure and gravitational (force) pressure).

Carl Friedrich von Weizsäcker and Hans Bethe, provided the first predictions of the carbon cycle in the 1930s.
https://ui.adsabs.harvard.edu/abs/2018PhP...20..124W/abstract

Outside of stars, one needs magnetic confinement to maintain a plasma long enough to develop fusion, with light nuclei like d and t, or 3He; intertial confinement works on smaller time scales. As the atomic number of nuclei increase, the energy required to induce fusion increases (increased Coulomb repulsion), and the energy losses due to bremsstrahlung and recombination increase.

With fission devices and fusion devices, there is a tremendous number of neutrons produced, and these neutrons will flow out of the detonation plasma into surrounding atmosphere and ground where they will likely be absorbed and transmute nuclei. That is independent of the fission products, which are released to the environment.
 
  • Like
Likes ohwilleke, Nugatory and vanhees71

Related to Why can't nuclear reactions burn the atmosphere

1. Why can't nuclear reactions burn the atmosphere?

Nuclear reactions cannot burn the atmosphere because the conditions necessary for nuclear fusion or fission to occur are not present in Earth's atmosphere. These conditions include extremely high temperatures and pressures, which are only found in the core of the sun or in nuclear reactors.

2. Can nuclear reactions cause a chain reaction that would burn the atmosphere?

No, nuclear reactions cannot cause a chain reaction that would burn the atmosphere. This is because the atmosphere is primarily made up of gases such as nitrogen and oxygen, which are not suitable for sustaining a nuclear chain reaction. Additionally, the concentration of radioactive materials in the atmosphere is too low to initiate a chain reaction.

3. Is it possible for a nuclear explosion to ignite the atmosphere?

No, it is not possible for a nuclear explosion to ignite the atmosphere. The energy released from a nuclear explosion is not enough to heat up the entire atmosphere to the temperatures required for nuclear fusion or fission to occur. Additionally, the explosion would need to take place in an oxygen-rich environment, which is not present in the upper layers of the atmosphere.

4. Could a malfunction in a nuclear power plant lead to the burning of the atmosphere?

No, a malfunction in a nuclear power plant cannot lead to the burning of the atmosphere. Nuclear power plants are designed with multiple safety features to prevent any catastrophic events, including the release of radioactive material into the atmosphere. Even in the worst-case scenario, the amount of radioactive material released would not be enough to cause a chain reaction in the atmosphere.

5. Is there any risk of nuclear reactions burning the atmosphere in the future?

No, there is no risk of nuclear reactions burning the atmosphere in the future. Nuclear reactions require specific conditions to occur, and these conditions are not present in Earth's atmosphere. Additionally, nuclear technology and safety protocols have advanced significantly, making the likelihood of a catastrophic event even lower.

Similar threads

  • Sci-Fi Writing and World Building
Replies
21
Views
1K
  • Science Fiction and Fantasy Media
Replies
17
Views
4K
  • High Energy, Nuclear, Particle Physics
Replies
30
Views
10K
Replies
1
Views
3K
Replies
14
Views
8K
  • Other Physics Topics
Replies
0
Views
771
Replies
2
Views
3K
  • Astronomy and Astrophysics
Replies
1
Views
3K
Replies
2
Views
4K
  • General Discussion
Replies
1
Views
8K
Back
Top