Yes, in the sense that fusion requires incredibly accurate magnetic fields to maintain, and the second there's any issue with the reactor chamber, the reaction will just stop. The reactor itself cannot explode in any way shape or form, because there is nothing in there to explode. It also doesn't produce any radioactive isotopes while running, it just fuses(hence fusion) hydrogen into helium, just like the sun does. You can just capture this helium and sell it to make baloons if you want.
The reaction itself kicks off a huge amount of neutron radiation, which eventually makes the reactor chamber radioactive - that is the only radioactive waste that will have to be disposed safely eventually. But neither the fuel nor the resulting product are radioactive.
General Fusion's approach doesn't use magnetic confinement. Instead, they use liquid metal and pistons to create the pressures needed for fusion. The liquid metal then absorbs the heat energy which is extracted in the usual way.
What is the sort of lifetime (ball-park) that one might expect before neutron saturation of the reactor walls becomes a serious concern and the reactor has to be scrapped?
You can read about stuff like that in some of the ITER technical reports. They actually want to use that neutron radiation to generate tritium, and feed that back into the reactor.
I don’t think the reactor would be scrapped, just shutdown for maintenance.
The General Fusion design covers the walls with a molten mix of lead and lithium held in place by spinning the chamber. The lithium turns to tritium when you bang on it with a neutron to crease more inputs to the D-T fusion process. And lead doesn't really mind getting hit with neutrons. From the diagrams on Wikipedia[1] it looks like there is some normal metal exposed which might get neutron activated.
Most of the energy that is produced is in the neutrons, so it will be transferred as heat in whatever shield captures the neutrons and which will become radioactive.
So most of the heat will have to be extracted from a radioactive material, with similar precautions like in fission reactors, where the heat is extracted from the radioactive nuclear fuel.
I am very skeptical that fusion of deuterium with tritium or of deuterium with deuterium will ever produce "clean energy", even if they are the easiest fusion reactions, due to the relatively low temperatures required for them.
It still remains to be proven whether the radioactive waste for a fusion reactor of the kinds attempted now will be less than for a fission reactor.
>>It still remains to be proven whether the radioactive waste for a fusion reactor of the kinds attempted now will be less than for a fission reactor.
I wonder, how can this possibly be even a question? Fission based reactors obviously have the same or worse problem of irradiating the entire reactor enclosure and everything around it, so that's at best the same as a fusion reactor + they produce tonnes of very highly radioactive waste that will be radioactive for millennia.
Materials activated through neutron bombardment aren't radioactive for anywhere near as long. And to add to that, nearly all elements produced in a fission reactor are highly toxic in addition to being radioactive - in a fusion reactor if your steel containment chamber becomes activated, you just have radioactive steel, not one of the many many dangerous heavy metals produced through fission.
What you say is true of light water reactors, a 1950s design.
LFTR would be far better. Neutrons breed new fuel, and it consumes virtually all the radioactive fuel with "waste" that rapidly becomes non-dangerous within a month.
So I would guess neutron degradation of the equipment/vessel/reactor will probably be a similar problem in both cases.
The waste really only remains radioactive for a month or so? Not 10k years? Is that just because the other radioactive waste is consumed as fuel, or is that generally true of what it produces?
I'm not a nuclear engineer, but one of the LFTR videos seemed to comprehensively break down the nucleotide chains, and yes the fundamental breeding ability I think helps.
IIRC people have stated that the breeding could also reprocess the bad millenial-scale waste from LWR into usable fuel or other isotopes in MSRs, although maybe not in LFTR.
If we had a decent LFTR industry, we could probably have more specialized MSRs to deal with the "legacy" waste and breeder reprocess into new fuel or other stuff.
The chemists from ORNL seemed pretty amazing. They had all the work done for separating out the byproducts for use in other applications.
The reaction itself kicks off a huge amount of neutron radiation, which eventually makes the reactor chamber radioactive - that is the only radioactive waste that will have to be disposed safely eventually. But neither the fuel nor the resulting product are radioactive.