Nuclear fusion has encountered a shortage of tritium • Hacker News Board

Re: Nuclear fusion has encountered a shortage of tritium

#131

Post by westcort » Sat, May 21, 2022, 2:44 PM UTC

dang wrote: post #120

westcort wrote: post #59

My key takeaways: * In a perfect world, there would be a more ambitious program developing the breeding technology in parallel to ITER, Willms says, so that by the time ITER has perfected the fusion reactor there’s still a fuel source to run it * Like many of the most prominent experimental nuclear fusion reactors, ITER relies on a steady supply of both deuterium and tritium for its experiments * When it’s finally fu…

Can you please stop doing this? I'm sure these comments are well intentioned, but the pattern has become repetitive ( https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que... ) and anything this repetitive is bad for curiosity ( https://hn.algolia.com/?dateRange=all&page=0&prefix=false&so... ). HN threads are supposed to be conversations, and conversation involves people interacting with each other.

Okay I will not post these anymore. I might share the summarization algorithm I wrote that enables me to create these quickly, though. Thanks for helping me understand the ethos of curiosity and the diffs as the underlying principles.

Re: Nuclear fusion has encountered a shortage of tritium

#132

Post by pfdietz » Sat, May 21, 2022, 3:01 PM UTC

john567 wrote: post #122

ncmncm wrote: post #108

Earlier quoted context omitted.

There will never be any marketable fusion power at all, never mind "infinite". Power from Tokamaks necessarily costs at least 10x power from fission, and fission is already not competitive, and gets less so each year.

??? Fission is incredible profitable. It's the only source of reliable electricity we have (with a negligible CO2 impact). The only reason fission isn't more profitable is politics. Politics are making investment and research into fission needlessly costly.

Fission is grossly uncompetitive. That's why there's never been a single merchant fission power plant built anywhere in the world.

Re: Nuclear fusion has encountered a shortage of tritium

#133

Post by pfdietz » Sat, May 21, 2022, 3:04 PM UTC

DennisP wrote: post #82

gitfan86 wrote: post #69

Earlier quoted context omitted.

Last week Elon explained that the problem of fusion is that it will be more expensive than solar and wind.

The real question is whether it's more expensive than solar/wind plus the batteries required for dispatchable power. The answer depends on the reactor design, which Elon doesn't know. There are a lot of possibilities, and if the first ones are too expensive, later ones might not be.

Almost certainly it will be more expensive than renewables + storage (note the importance of hydrogen there.)

The cost of renewables + storage to provide "synthetic baseload" is likely less than fission. And DT fusion is likely more expensive than fission.

https://model.energy/

Re: Nuclear fusion has encountered a shortage of tritium

#134

Post by pfdietz » Sat, May 21, 2022, 3:05 PM UTC

DennisP wrote: post #84

G3rn0ti wrote: post #15

I thought the end game was aneutronic fusion using lithium and deuterium anyway creating only charged particles instead of high energy neutrons that are dangerous and damaging to the reactor. If nuclear fusion ever wants to be commercially viable, it must not depend on tritium.

Helion is working on a deuterium/helium-3 reactor, which if it works will produce only 6% of its energy as neutron radiation. YCombinator was an investor. They've run six reactors and are building a seventh now for a net power attempt in 2024. There are also at least four companies working on proton-boron fusion, though all but one are very small. (TAE is the exception.)

Except they need a DD reactor to make the 3He to fuel the D3He reactor.

Re: Nuclear fusion has encountered a shortage of tritium

#135

Post by pfdietz » Sat, May 21, 2022, 3:08 PM UTC

DennisP wrote: post #90

GuB-42 wrote: post #26

Earlier quoted context omitted.

Is there any other approach to fusion than ITER? I mean fusion capable of practical power generation. D-T fusion is the easiest, and yet super hard. Tokamaks are the only design that we know how to build in order to meet the goal, with maybe stellerators in second position. Inertial fusion work for scientific and military experiments, but are far from being a usable power source. Things like fusors and its derivative…

Most conservatively, there are tokamaks that use more modern superconductors, able to support much stronger magnetic fields. Tokamak output scales with the fourth power of the magnetic field, so that allows the same output as ITER from a much smaller, cheaper reactor. The MIT spinoff CFS is doing this, along with Tokamak Energy in the UK. CFS is shooting for a net power attempt in 2025. There are also various alterna…

All the DT approaches suffer from poor volumetric power density, for fundamental reasons independent of the details of magnetic fields or confinement schemes. For that reason I feel Helion's approach is the least dubious.

Re: Nuclear fusion has encountered a shortage of tritium

#136

Post by DennisP » Sat, May 21, 2022, 3:40 PM UTC

pfdietz wrote: post #134

DennisP wrote: post #84

Earlier quoted context omitted.

Helion is working on a deuterium/helium-3 reactor, which if it works will produce only 6% of its energy as neutron radiation. YCombinator was an investor. They've run six reactors and are building a seventh now for a net power attempt in 2024. There are also at least four companies working on proton-boron fusion, though all but one are very small. (TAE is the exception.)

Except they need a DD reactor to make the 3He to fuel the D3He reactor.

The plan is to do that in the same reactor.

Re: Nuclear fusion has encountered a shortage of tritium

#137

Post by DennisP » Sat, May 21, 2022, 3:51 PM UTC

pfdietz wrote: post #133

DennisP wrote: post #82

Earlier quoted context omitted.

The real question is whether it's more expensive than solar/wind plus the batteries required for dispatchable power. The answer depends on the reactor design, which Elon doesn't know. There are a lot of possibilities, and if the first ones are too expensive, later ones might not be.

Almost certainly it will be more expensive than renewables + storage (note the importance of hydrogen there.) The cost of renewables + storage to provide "synthetic baseload" is likely less than fission. And DT fusion is likely more expensive than fission. https://model.energy/

Yes, we discussed that pretty extensively the other week. It starts out with unrealistic assumptions for fission, including a 25-year lifespan (compared to the actual average age of US reactors of forty years) and twice the discount rate for fission as for everything else. Fix those things and nuclear does better.

It also uses US fission prices, which are higher than in most of the world. On top of that, the US has unusually good geography for both wind and solar. Nuclear is much more competitive in many other countries. One ironic example is Germany, where the model suggests a 100% nuclear grid even at US nuclear costs, as long as the lifespan and discount rate are corrected.

Re: Nuclear fusion has encountered a shortage of tritium

#138

Post by pfdietz » Sat, May 21, 2022, 4:33 PM UTC

DennisP wrote: post #137

pfdietz wrote: post #133

Earlier quoted context omitted.

Almost certainly it will be more expensive than renewables + storage (note the importance of hydrogen there.) The cost of renewables + storage to provide "synthetic baseload" is likely less than fission. And DT fusion is likely more expensive than fission. https://model.energy/

Yes, we discussed that pretty extensively the other week. It starts out with unrealistic assumptions for fission, including a 25-year lifespan (compared to the actual average age of US reactors of forty years) and twice the discount rate for fission as for everything else. Fix those things and nuclear does better. It also uses US fission prices, which are higher than in most of the world. On top of that, the US has u…

And as I told you last week, the numbers are actually optimistic compared to US (or actual EPR) numbers. In particular, it assumed the reactor cost 6000 euro per kW, which is considerably less than what EPR ended up costing.

Re: Nuclear fusion has encountered a shortage of tritium

#139

Post by DennisP » Sat, May 21, 2022, 4:42 PM UTC

pfdietz wrote: post #138

DennisP wrote: post #137

Earlier quoted context omitted.

Yes, we discussed that pretty extensively the other week. It starts out with unrealistic assumptions for fission, including a 25-year lifespan (compared to the actual average age of US reactors of forty years) and twice the discount rate for fission as for everything else. Fix those things and nuclear does better. It also uses US fission prices, which are higher than in most of the world. On top of that, the US has u…

And as I told you last week, the numbers are actually optimistic compared to US (or actual EPR) numbers. In particular, it assumed the reactor cost 6000 euro per kW, which is considerably less than what EPR ended up costing.

And I linked you a paper surveying global nuclear costs, showing much lower costs in many areas and no overall trend of increasing costs. Here's the paper again:

https://www.sciencedirect.com/science/article/pii/S030142151...

Skip down to Figure 12 for a quick summary.

Re: Nuclear fusion has encountered a shortage of tritium

#140

Post by ASalazarMX » Sat, May 21, 2022, 4:56 PM UTC

ncmncm wrote: post #109

adrian_b wrote: post #78

Earlier quoted context omitted.

The kinds of fusion generators that are considered for the near future produce most of their energy as kinetic energy of neutrons. The energy of the neutrons is transformed into heat by adsorbing them into some shielding walls. The materials for those walls will be chosen to minimize the quantity of radioactive waste that is produced by the extremely intense neutron irradiation, but it is impossible to avoid complete…

You could absorb neutron flux in a thousand tons of molten 6Li/7Li, and then try to separate grams of tritium from that thousand tons of molten, extremely inflammable metal, on a continuous basis. Good luck with that. Renewables do not incur such operating expenses. Put renewables and a fusion reactor on the grid, and fusion would never, ever win a bid. "Fusion .. will generate ... less ... than fission"? The whole d…

I dug more about this because it's an interesting topic. Basically we don't know how long a fusion generator will last before radioactivity forces its decommissioning because none exist yet, but fortunately it's short-life isotopes, about 50-120 years before they become safe. Orders of magnitude better than fission waste.

I don't know about fusion vs renewables, because renewables are better, but they need a lot of non-renewables to be manufactured. If a fusion reactor lasted 100 years, it would be a much better option than renewables.