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Fusion Reactor Breaks Even
mysqlbytes writes "The BBC is reporting the National Ignition Facility (NIF), based at Livermore in California, has succeeded in breaking even — 'During an experiment in late September, the amount of energy released through the fusion reaction exceeded the amount of energy being absorbed by the fuel — the first time this had been achieved at any fusion facility in the world.'"
why is the bbc first to report on this? It happens in CA, and we get scooped? wtf??
FTFA:
"Soon after, the $3.5bn facility shifted focus, cutting the amount of time spent on fusion versus nuclear weapons research - which was part of the lab's original mission."
Makes you wonder where we'd be now if we stopped pissing about on weapons research.
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The RESEARCH is expensive. The base fuel comes from seawater and costs hundreds of dollars per pound. The energy in one pound is equal to millions of pounds of coal.
Even better, most of the fuel cost is the energy needed to separate the fuel from seawater. With self-powering desalination / fusion plants, fuel cost would be pennies.
The difficulty is that conditions have to be just perfect to keep the reaction going. If anything isn't just right, the process stops and you're left with what looks and acts like a baby aspirin. That's awesome for safety, though. That's the opposite of fission, where they are trying to keep a naturally volatile reaction under control.
There are still three things missing:
1. Scientists are only counting the laser energy absorbed by the fuel. Not all of the laser energy is absorbed by the fuel.
2. Lasers are not 100% efficient. They take lot more energy than they give out.
3. The generated energy is in the form of heat. Converting it to electrical is not there.
Overall, the efficiency is still less than 1%. Far away from anything usable.
The energy in neutrons is not unrecoverable. You would probably need to use a heat engine to get the energy out, but at high temperatures that could be efficient.
The break even point is somewhat arbitrary, as any neutrons out will give you some heat. All you have to do is harness it. In practice, though, about 10X break even is thought to be necessary. To be economic you would need much more, especially since fission is so easy. Most fusion reactions will also create waste, and any reaction that creates copious neutrons will be a proliferation risk. Aneutronic fusion is very hard, and the NRC would probably crush anything else.
It's a nice technical achievement, but I can't see us using it to produce electricity.
a,e,i,o,u and sometimes w and y (at be if of up cwm by)
One of the big criticisms of the NIF is that the design is basically unsuited to capture more than a slim percentage of the energy released. It's good for weapons research because it works vaguely the same way a bomb does - rapidly compressing fuel in a burst. But it doesn't really have a mechanism for capturing that energy, unlike tokamak-based designs.
Based on the summary (still reading TFA itself), it sounds like they broke even in terms of the energy input into the fuel being less than the total amount released from the reaction. But to be a self-sustaining, practical fusion power source, it needs to extend that two directions - first, by breaking even in terms of power into the entire system being less than that released, and second by breaking even in terms of power captured, not just power generated. The former is straightforward - more efficient lasers, more efficient reactions - but, and this is from a non-engineer's perspective, I don't think the latter will be simple.
There are different ways to break-even.
Scientific break-even means the energy you've provided to the fuel's environment is less than the energy the reaction liberates. This is what is claimed here, although even then they're squinting a bit by only counting the light absorbed by the fuel pellet.
Engineering break-even accounts for the inefficiency in providing energy to the reaction (losses in laser beam generation and transmission, in this case) and inefficiency in converting the reaction energy into electricity (or other useful form.) Once you've reached engineering break-even, you have a facility which, provided with fuel, will provide you with electricity.
Economic break-even is when the amount of electricity generated is sufficient to pay for the capital, consumables and maintenance (and perhaps waste disposal and decommissioning) cost of the facility.
Incidentally, I thought magnetic confinement fusion reactors had reached scientific break-even a decade or two ago. I haven't found any support for this belief in a quick web search, so maybe I'm delusional.
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
Why? Nobody else does.
Coal is considered as present in the boiler - no taking into account powering sootblowers, crushers, conveyors, trains and actually getting the stuff out of the ground. That total consumption is not so easy to work out and will vary widely anyway.
Nuclear does the same thing and starts with the assumption that fuel rods appear by magic, which although dishonest is understandable if they are comparing it with coal in the situation above.
This is cutting edge stuff and we're only now getting the first of the 1980s design of the AP1000 nearing completion - "commercial use" is not going to be a consideration for a while no matter how good it is. It takes a lot of work to turn a breakthrough into a commodity.