## Tuesday, October 08, 2013

### NIF: laser-powered fusion creates more energy than it consumes

Peaceful fusion may be just 49, and not 50, years away now

This project has been discussed twice on this blog.

In May 2009, I mentioned that the National Ignition Facility in Livermore near San Francisco (StreetView) was activated – Chu and Schwarzenegger couldn't miss this opportunity for self-promotion.

In January 2010, it was projected – and we absorbed the information – that the facility with 192 powerful lasers heating and pressing a piece of hydrogen fuel should be able to produce more energy than what they invest.

Ladies and Gentlemen, the D Day apparently came yesterday. The countdown had to be exciting:

As Fox News, BBC, and a dozen of other major mainstream media told us, they compressed the fuel so that for 14 nanoseconds, it was producing the power of 350 terawatts, hundreds of times exceeding the whole consumption (power) by the United States of America (during the same 14 nanoseconds).

The single blast is cheap – it only costs between $5 and$20 for lasers to blink. You must also add the $3.5 billion price of the facility so it's between$3,500,000,005 and $3,500,000,020. ;-) So the progress is very promising. The only problem – which will remain a challenge for the future – is the middle word in the name of the facility. It's an "ignition" facility but no ignition has actually taken place and there is a risk that there won't be any ignition seen for those$3.5 billion, ever. Maybe it's not necessary?

Half-a-minute introduction to the project for the busy TRF readers... Those who can afford to spend five minutes, go here.

The next breakthrough will occur once they hire Ron Maimon who will cleverly turn all the lasers off and place the whole facility in a giant refrigerator, starting cold fusion in this way. ;-)

1. Maybe it's not necessary?

I'm guessing that's tongue-in-cheek? It seems unlikely that something with an energy return of less than 200% could be economically viable.

2. "for 14 nanoseconds, it was producing the power of 350 terawatts" - that's an ignition for me. Don't even think of maintaining that power for 14 seconds. Exactly 0.000% of that energy was harvested to generate power,

3. What a waste of money :-) for funders at least. Anyway... today is Juno Earth flyby day! Cheers!

4. Let us be fair. An airplane carrier costs more than twice the price of this experiment, and it seems it is a successful experiment that might be used to ignite fusion in a controlled way. An airplane carrier could go to the bottom of the sea in case of war.The knowledge from this experiment will surely take the fusion process further.

60 years ago I was contemplating graduate school and one of the options was fusion experimental. So it is not just 50 years we are waiting for controlled fusion. My son, a physicist, is working on the diagnostics of ITER. I do not think he expects to see commercial fusion before he retires. Nevertheless, harnessing fusion is necessary for the continuation of our energy hungry civilization, and it will be done, one way or the other.

We have a modern greek proverb : "the bean bag fills up bean by bean", from the time before the harvesting tractors were invented.

5. The basic problem with all these fusion devices is cost and size. Assuming they can be made to work, which is highly dubious, no one has come close in over 40 years, they would cost about 10 times as much as a fission reactor of the same power output. Therefore, they will have no possible commercial or military use, "Aliens" not withstanding.

That being the case, aircraft carriers are clearly a better investment, because they keep open the oil-shipping lanes. We will be mining methane gas hydrates from the sea before these failed experiments are finally ended.

6. My pessimism for peaceful fusion power is not as absolute as others here. Perhaps it is with regard to ITER and the NIF, but in the not so distant future there might be advances in magnetic confinment, materials sciences, and manufacturing that allow for an inexpensive compact tokamak. I suspect that these new avenues are already being explored by at least one large, technically capable corporation.

7. An optically-imploded microscopic cryogenic wet hydrogen bomb, most of whose energy comes out as fast neutrons, is crap at all levels. Never implode solid pellets of (Li-6)D (dry H-bomb), LiBH_4, or (Li-6)BD_4 (silly and expensive, hence a priority).

B(10) + proton fusion gives three alpha particles (helium being in short supply). Clean, cheap, and recyclable! Aim Fermilab at a chunk of boron (600 keV capture resonance - piddles, even given electron shielding) and power Chicago. No, wait...build another Fermilab at twice the hardware cost under Lake Michigan (radiation shielding) to pay back political debts. Build, then freeze everything until environmental studies are completed. Who hears the algae when they cry?

8. I would not call 5-20\$ per 1 kWh of heat cheap :)

9. strictly speaking...Oct 10, 2013, 2:08:00 AM

I personally believe that the inertial confinement method is a dead end for commercial power generation. Getting useful power out of it is probably going to be so expensive that there's no point in bothering.

However, this doesn't mean that this test reactor is a bad investment for the department of defense. It's pretty much the only way to circumvent the total test ban treaty for resarching processes inside thermonuclear weapons. It's a reliable way to do "clean" fusion experiments and get uncorrupted data out of it. There's also other stuff you can do with it, such as breeding Tritium and He-3 for further research.

The likely result of this will probably be improvements in current bomb designs, with the possibillity of it leading to completely new designs, such as practical pure fusion bombs. It is also a good way to provide enough active jobs in the field to maintain a constant flow of new nuclear engineers that are potentially capable of designing, building, and maintaining the US nuclear arsenal, which is not a trivial task.

If you're going to have an overinflated defense budget anyway, this is one of the few investments that would lead to something that is actually useful in a worst-case total war scenario. Investing a similar sum into say another aircraft carrier would just leave you with another asset that is defenseless against an ICBM.

10. Regardless of whether the topic be fusion or anything else involving prediction, I don't understand why so many people in comments threads (on many different websites) feel so confident in making one prediction or another, e.g., the opposite. They say things like, "Bullshit! It won't happen." - "Bullshit! It will happen."

11. Mmm... good point! :-)

12. You are correct that ignition did not occur. Ignition is necessary, if inertial confinement fusion is ever to be used for commercial power.

"Ignition" in this context means that the thermonuclear alphas (from D + T -> He + n) are the dominant, or a significant, heat source of the compressed fuel. There is some fuzziness in this definition. Conventionally, people have used a criteria for ignition that the energy in thermonuclear neutrons exceeds the input laser energy (Gain~1). An ignited NIF capsule is predicted to produce Gain ~ 10.

This is certainly not what has yet occurred at NIF. They are claiming that the energy in thermonuclear neutrons is somewhat higher than the x-ray energy absorbed by the fuel. Recall that NIF is operating in indirect drive, where the laser hits a gold canister that then functions as an x-ray oven. The x-ray energy absorbed by the fuel is much less than the laser energy, so the gain is still much less than 1.

13. This is all just hype. Livermore keeps dumbing down the definition of "breakeven." For the record, they explicitly accepted "fusion energy out equals laser energy in" as the definition of ignition back in the 90's before the ICF Committee of the National Research Council. I heard it with my own ears. That definition would put them on a level playing field with magnetic fusion. It's embarrassing that they would stoop to this, especially when it's so easy to make the case for the NIF using the truth instead. The facility meets and exceeds its design specs, is highly precise, and has fantastic diagnostics. It was built and funded primarily as an above ground experimental facility for the nuclear weapons program. It will serve that mission extremely well whether it achieves ignition or not. Such facilities give the U.S. a bit leg up over the competition in maintaining the safety and reliability of our arsenal. With it, we have a big advantage as long as nuclear testing is not resumed. That's the argument that should be used to convince Congress to maintain funding.

14. The input energy you're referring to is that amount absorbed by the hydrogen fuel. This is significantly less than the input laser energy due to inefficiencies within the system.