National Ignition Facility

[crowberry]

NIF reports on progress using a diamond target and uranium hohlraum:

https://physicsworld.com/a/giant-lasers ... on-energy/
https://journals.aps.org/prl/abstract/1 ... 120.245003

[CharlesKramer]

No doubt everyone's seen this (below).

I am no physicist, but....

-- isn't "chain reaction" misleading when used in connection with fusion?

-- how could NiF even theoretically achieve ignition? It is a pulse device, kinda like an old school flash camera storing up a charge with capacitors, then FLASH. The machine seems uniquely unsuited to achieve ignition (unless the excess energy powers the next FLASH)

NiF is the successor to a long line of failed smaller devices, so the apparent fact this one has achieved something is good news, I guess.

Looking forward to comments...

CK

https://www.yahoo.com/now/why-u-fusion- ... 10961.html

For decades, fusion scientists have attempted to create reactions by essentially shooting high-powered laser beams at hydrogen atoms. However, they’ve struggled to reach a phenomenon called “ignition,” which is a break-even point when a fusion reactor produces more energy than it consumes.... Researchers have gotten close in the past—the NIF was able to produce 70 percent of the energy needed to begin a fusion reaction in 2021. The lab might now be a massive step closer after new experiments reportedly resulted in a net energy gain, which means it extracted more energy from the fusion reaction than was required to trigger it, according to The Financial Times

But wait, isn’t that the same thing as ignition? Not quite. Ignition requires the nuclear reaction to be self-sustaining, which means that it creates a chain of reactions that create other reactions and so on. When that happens, things start to really cook (just make sure the robot octopus arms you’re using for the experiment don’t get damaged in the process).

[Skipjack]

For devices like NIF, definition of ignition is a bit sketchy. Check this paper for some more info:
https://arxiv.org/pdf/2105.10954.pdf

[CharlesKramer]

> Check this paper

Excellent! Thx - CK

[crowberry]

Fusion gain has been demonstrated for the first time!!! The NIF shot from the 5th of December 2022 had a 300 MJ wall plug input for a 2.05 MJ laser output and 3.15 MJ of fusion yield. So the Q value was about 1,5. It was reported that the fuel burn up rate in this shot was about 4 %. The NIF team will rather likely be able to significantly improve on this result in the future with their newly learned lessons.

This is what we have been waiting for a long time also on this forum. Obviously this will have a huge positive impact on fusion in general. This shows the first way to achieve controlled fusion gain in the laboratory. It will be even more interesting to see how the announced plans for fusion gains turns out in the coming years from the private fusion companies, which are more advanced on the road toward parctical fusion power plants.

[CharlesKramer]

If I understand correctly, the fact any fusion effort using any method achieved fusion gain must be encouraging for all the other efforts. So: it *can* be done (without, you know, a bomb). So cheers for stubbornly pursuing a goal! It's been a long road for NiF and its many laser/target predecessors ("Shiva" etc.). But...

which are more advanced on the road toward practical fusion power

Was NiF ever imagined to be practical?

In my "I am not a physicist" ignorance it always seemed silly -- all those acres of amplifiers and capacitors all focusing multiple lasers on a teeny weensy dot, and then one shot at a time. Even if that dot (well, hohlraum) could be rapidly replaced, and even the machine could charge up and pulse many times a minute it doesn't sound practical.

Was their ever a plan to do that -- charge and pulse frequently enough to generate useful power ? Just curious.

[mvanwink5]

Was NiF ever imagined to be practical?

I realize some are celebrating, but my understanding was this was a device for bomb research not for commercial electric power. I get in a celebratory mind frame when the announcements by groups that have a clear shot at commercial power are made. With that in mind, until a Tokamak project has a solution for the first wall issue they are off my list (others are less picky for their own reasons).

[crowberry]

I
Was NiF ever imagined to be practical?

In my "I am not a physicist" ignorance it always seemed silly -- all those acres of amplifiers and capacitors all focusing multiple lasers on a teeny weensy dot, and then one shot at a time. Even if that dot (well, hohlraum) could be rapidly replaced, and even the machine could charge up and pulse many times a minute it doesn't sound practical.

Was their ever a plan to do that -- charge and pulse frequently enough to generate useful power ? Just curious.

The primary goal of the NIF is to do military research, high density physics research and show that fusion ignition is possible as stated in the name of the facility. NIF did have an energy research program called LIFE, but that was officially terminated because of the slow progress on NIF in 2014.

In 2008 LLNL began the Laser Inertial Fusion Energy program (LIFE), to explore ways to use NIF technologies as the basis for a commercial power plant design. The focus was on pure fusion devices, incorporating technologies that developed in parallel with NIF that would greatly improve the performance of the design.[101] In April 2014, LIFE ended.

https://en.wikipedia.org/wiki/National_ ... n_Facility

NIF has inspired a handful companies to try to develop ICF based reactors. The challenges are great of course and it will take time and money to make progress. Economics of fusion will be an requirement for success and that is where the other concepts are much more practical and advanced compared to ICF.

The NIF team has to be congratulated for the accomplishment as it it is indeed a long sought milestone to demonstrate in the laboratory fusion gain.
Hopefully it will not take much more time until we will have similar announcements from other groups.

[paperburn1]

Fusion gain has been demonstrated for the first time!!! The NIF shot from the 5th of December 2022 had a 300 MJ wall plug input for a 2.05 MJ laser output and 3.15 MJ of fusion yield. So the Q value was about 1,5. It was reported that the fuel burn up rate in this shot was about 4 %. The NIF team will rather likely be able to significantly improve on this result in the future with their newly learned lessons.

Read the paper and was disappointed.while the energy at the chamber was 1.5 times higher than input power after you take the total power used to make that one shot the total power was about 100 times less. so congratulation on you shot producing more power than imputed at the chamber. BUT and its a big BUT the output of the chamber was only 1 percent of the energy used to charge up the device. so in reality Q=.01. I am going to go kick the dog now. (just an expression , I love my doggie.)

[charliem]

And they did it again: US scientists achieve net energy gain for second time in nuclear fusion reaction

I was slightly worried that last December's scientific break-even could be a fluke. Glad it was not.

How long until the next group gets there. A couple years? More? Less? We'll see.

[Skipjack]

I guess less than 2 years. That would be Helion and/or Zap. Less likely but not zero possibility candidates are LPPFusion, Horne, Pulsar Fusion and Avalanche.

[crowberry]

CFS is aiming for 2025 with the SPARC and General Fusion today issued a press release aiming for 2026 with their Lawson Machine 26 (LM26). Tokamak Energy and TAE Technologies also have detailed plans. The next step after achieving scientific breakeven is to do that repeatedly and reliably, which requires that instabilities, plasma impurities, geometric imperfections and such factors are under control. That will not be an easy task to accomplish. And then the fusion gain needs to be increased to power plant levels, so there is still much ground to cover until we start seeing fusion power plants around.

[Skipjack]

CFS is aiming for 2025 with the SPARC and General Fusion today issued a press release aiming for 2026 with their Lawson Machine 26 (LM26). Tokamak Energy and TAE Technologies also have detailed plans. The next step after achieving scientific breakeven is to do that repeatedly and reliably, which requires that instabilities, plasma impurities, geometric imperfections and such factors are under control. That will not be an easy task to accomplish. And then the fusion gain needs to be increased to power plant levels, so there is still much ground to cover until we start seeing fusion power plants around.

Yeah, I was only mentioning those that are less than 2 years away (potentially!). CFS, GF and TAE will be longer. CFS Q>1 attempt has shifted to the right to 2026 as well.

[crowberry]

Yeah, I was only mentioning those that are less than 2 years away (potentially!). CFS, GF and TAE will be longer. CFS Q>1 attempt has shifted to the right to 2026 as well.

Skipjack, I did not know that the SPARC Q>1 target year has moved to 2026. Where did you see that?

[charliem]

It is 1994 and the Internet again (or 1765 and steam engines, or 1906 and electronics, or 1980 and personal computers, etc., etc.).

When Internet was about to change everyone's world, the overwhelming majority were completely oblivious to it.

Now it is controlled nuclear fusion. Again, we are on the threshold of deep changes in our lives. It is going to start with the global economy but soon the effects will reach most aspects of our societies: transport, water availability, food production, geopolitics, wealth distribution, weapons, wars, and the military, space exploration, popular culture, and so on.

Interesting times ... once more.

edits: grammar and spelling