If Fusion Is the Answer, We Need To Do It Quickly

Lasrick writes: Yale's Jason Parisi makes a compelling case for fusion power, and explains why fusion is cleaner, safer, and doesn't provide opportunities for nuclear smuggling and proliferation. The only downside will be the transition period, when there are both fission and fusion plants available and the small amount of "booster" elements (tritium and deuterium) found in fusion power could provide would-be proliferators what they need to boost the yield of fission bombs: "The period during which both fission and fusion plants coexist could be dangerous, however. Just a few grams of deuterium and tritium are needed to increase the yield of a fission bomb, in a process known as 'boosting.'" Details about current research into fusion power and an exploration of relative costs make fusion power seem like the answer to a civilization trying to get away from fossil fuels.

Comments

Did I miss the breakthrough?

[sphealey]

Did I miss the part where the human race had a miraculous breakthrough in fusion technology? Even setting aside the expected issues with neutron radiation (sorry, no Mr. Fusion Home Energy Kit) there isn't any fusion technology today that is even close to breakeven on an experimental basis. As for commercial operations...

Re: Fusion Confusion

[gewalker]

Well, since the whole purpose of fusion reactors is to make commercially useful power, it is pretty clear that we do not have a working fusion reactor by any reasonable definition.

Despite having spent billions (22 Billion USD on hot fusion research by US alone) on the problem so far, with billions yet to come, we do not have working fusion reactors. Even ITER will just be a prototype with no power generation at all. Cost to develop commercially, unknown but bound to be a lot of money.

The US alone has also spent around 15 Billion developing Fast Breeder reactors, and has little to show for it. Other countries have similar experience.

Estimated cost to develop commercial LFTR reactors seems to be in the range 3 - 20 Billion USD. A commercial LFTR prototype seems to be likely 1 billion USD by most observers.

And you still have to build the reactors -- that won't be cheap either. Every known possible solution to replacing our energy infrastructure has a large economic cost, and significant to large environmental cost as well. Kind of the way large-scale engineering works.

Yet the cost of doing nothing will be larger yet, at least eventually. Peak fossil fuel is coming sooner or later, even if you master shale and methane hydrates with high recovery rates and limited environmental impact. There are a lot of third-world people in this world that would gladly join the first-world lifestyle which puts a severe constraint on expanding fossil fuels usage to match the growth in demand.

Personally, the combination of LFTR and renewable sources seems most likely to me to be commercially successful by 2050. Why, because the needed development seem to be within or nearly withing the capabilities of current engineering in both cases. Engineers are very happy to deliver good enough when the perfect seems unattainable.

Re:Ready in 30 years

[Rei]

You're arguing against Tokamak fusion. But what about, say, HiPER? Looks to me to be a much more comercializeable approach, yet it's still "mainstream" fusion, just a slight variant on inertial confinement ala NIF to make it much smaller / cheaper / easier to have a high repeat rate (smaller compression pulse + heating pulse rather than a NIF-style super-massive compression pulse). The only really unstudied physics aspect is how the heating pulse will interact with the highly compressed matter; NIF and pals have pretty much worked out the details of how laser compression works out. Beyond this, pretty much everything else is just engineering challenges for commercialization, such as high repeat rate lasers, high-rate hohlraum injection and targeting, etc.

I've often thought (different topic) about how one can get half or more of fusion's advantages via fission if you change the game around a bit. Fusion is promoted on being passively safe (it's very hard to keep the reaction *going*, it really wants to stop at all times), it leads to abundant fuel supplies, and there's little radioactive waste (no long-term waste). But what about subcritical fission reactors? Aka, a natural uranium or thorium fuel target being bombarded with a spallation neutron source. Without the spallation neutrons, there's just not enough neutrons for the reaction, so the second the beam gets shut off, the reactor shuts down, regardless of what else is going on. It'd be a fast reactor, aka a breeder, aka, your available fuel supplies increase by orders of magnitude. And your long-term waste would be much, much less in a well-designed reactor. Spallation neutron sources have long been proposed as a way to eliminate long-lived nuclear waste by transmuting it into shorter-lived elements.