Hacker News Reader

Comment by MichaelCollins | Hacker News Reader

Little effect I think. Fusion power can do little that fission power can't do already, which is provide "free" power after you look past the cost to build and maintain the plant. The best advantage of fusion power is the public perception is presently better.

View on HN

Don't ignore the fact that uranium reserves would not last 100 years if we used it as our sole power source.

You should say "current" uranium reserves.

As demand goes up, so does supply, as additional reserves are prospected for and more costly uranium sources become economically viable.

There's not much reason to prove reserves if you won't be able to profitably mine them.

That seems like an estimate on the lower side, but still, in those 100 years we should be able to at least move to thorium, no? Which could last a lot longer.

There is enough uranium on Earth for getting all our current power for millions of years. (source: wikipedia)

There just isn't much at current prices, but fuel costs are not significant so prices cam rise.

Linky? It seems preposterous to assume that we will be able to map the energy budget of earthlings over a thousand millennia.

If you're comparing with solar, it seems fair to assume a level of energy usage that could reasonably be supplied by solar. We're not going to cover the planet in solar panels.

With that assumption, fission can last for a very long time if we get uranium from the oceans, and burn it in fast reactors. The oceans hold four billion tons of uranium, and with fast reactors we'd use it a hundred times more efficiently than we do today.

I said "all our current power" and I mentioned my source.

Is the safety profile any better? Or is it just public perception?

The safety profile is better with fusion, but I think you underestimate how good the safety profile of nuclear is these days. We haven't had any significant incidents since Fukushima, but we upgraded the safety mechanisms of our nuclear plants a lot based on that experience. Nuclear is on a path similar to flight, were we started off with very risky airline travel and got to a point where you are more likely to suffer an accident on the taxi on your way to the airport.

The lack of major radioactive waste is a plus, only the pipes and stuff inside the core of the reactor will have radioactive elements due to neutron activation. The only waste from it otherwise is helium (and tritium, which is re-used in the reaction later).

isn't helium valuable? seems like a good "waste" to produce

Yeah that's GP's point by the 'only'. It's 'waste' as in a byproduct.

It's part of the reason fusion's so sought after - it doesn't result in anything bad or that has to be carefully sequestered.

(Apart from extraordinary heat I suppose. Perhaps there's an argument the actual reactor would always be a pretty risky place. But any incident isolated at least, worst case a remote industrial building burns down beyond economical repair.)

The temperature is high but the amount of heat is no different than other thermal power plants. The atoms move very fast, but there aren't many of them.

Safe airships for all!

Very little will be produced. Indeed, a fusion reactor may leak more He from its cryo system than it creates.

There are major differences. For one, in case of catastrophic failure, the plasma will dissipate, its temperature will drop and the fusion reaction will stop.

It's a lot easier to build passively safe fission power plants than any sort of fusion power plant.

https://en.wikipedia.org/wiki/Passive_nuclear_safety

In case of catastrophic failure, thousands of tons of radioactivated lithium hydroxide burn uncontrollably, the smoke producing drain opener in contact with mucus membranes and lungs.

(Lithium hydride. The resulting caustic vapor is lithium hydroxide.)

This. The hard part is keeping it going, not getting it to stop.

Also, if I understand correctly, the waste products are a lot less nasty.

> The hard part is keeping it going, not getting it to stop.

I'm rather glad that doesn't apply to the fusion reactor in the sky that we'll be fully dependent on for a while yet.

Doesn't matter.

Public perception > reality.

Look at hydroelectric. Terrible for ecosystems, decent number of deadly failures over the years, way better perception and less pushback from the public than fission.

Dams are being taken down at an increasing rate as it is recognized that the fisheries they destroyed are far more valuable than anything they produce.

Fission power is already the second safest form of energy production, after hydro.

At least one source saying hydro causes more deaths than fission:

https://www.businessinsider.com/dam-safety-statistics-risk-o...

And the worst power plant accident ever was Banqaio Dam, which killed 26,000 people immediately, and another 150,000 or so in the aftermath.

Even with fusion, it's very clear that many politicians are afraid of it simply because of the word “nuclear” in it.

As nuclear fission, nuclear fusion might simply not be used because of that scary word alone.

It's possible that some Western countries will be that silly at first, but China certainly won't. Everybody else will come to their senses before long.

Reply on news.ycombinator.com