If the Sun produces harmful radiation, why does a Fusion Reactors not?


My understanding of fusion reactors they are creating a condition similar what is happening on the sun. However, one of the benefits that have been noted is that with fusion reactors, there isn’t nuclear waste created by harmful radioactive waste particles like there is with fission reactors.

While the sun is undergoing fusion reactions, it emits large amounts of harmful radioactive particles. Why is the same case not happening with a Fusion Reactor?

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5 Answers

Anonymous 0 Comments

The Sun creates harmful radiation, but not radioactive particles. Radiation can easily be shielded against because it’s just light with a very high frequency. In fact, a significant portion of the energy harvested from a fusion reactor comes from that radiation.

Anonymous 0 Comments

It does, but we need to contain the reaction for it to be useful. Part of that containment is keeping the harmful radiation from getting out

Anonymous 0 Comments

So there’s radiation and then there are materials that produce said radiation.

The sun produces harmful radiation but we’re mostly shielded from it by 100-ish km thick atmosphere, our buildings, our clothes, and sunblock (as a last resort when we cast off the buildings and clothes at the beach).

Nuclear fusion reactors produce the same or very similar harmful radiation but the reactors are shielded. The waste is mostly just helium that isn’t significantly dangerous.

Now, “old-school” fission reactors produce helium (we call it alpha radiation) but they also leave lots of material behind that is highly radioactive for a “brief” time (in geological or cosmological time scales). Also, it leaves behind some material that is moderately radioactive for much longer.

Either will kill you and it will probably hurt the entire time you’re dying.

Interesting tidbit of info: most of the “nuclear waste” from fission reactors is actually “spent nuclear fuel” and it still has tons of nuclear energy left in it. Like 90-95% of the potential energy remains. However, the engineering to get at that last 95% is difficult. There are new designs that could theoretically use up far more of the potential energy (and even make use of the spent nuclear fuel) but they still need a fair amount of R&D before they’re commercializable.

Anonymous 0 Comments

A fusion reactor will create neutrons as part of the reaction. They won’t get past the inner walls of the reactor, so not a danger outside, but materials in the wall will have to be chosen so as not to get damaged or made radioactive from the neutron bombardment. Tungsten carbide is being researched as a promising material to build the inner walls out of.

Anonymous 0 Comments

Also keep in mind that a nuclear reactor is gonna be fusing a few grams of hydrogen. The sun is fusing a few hundred million tons of the stuff, every second.