Helion Energy to demonstrate net electricity production by 2024

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jrvz
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Joined: Thu Jul 09, 2009 5:28 pm

Re: Helion Energy to demonstrate net electricity production by 2024

Post by jrvz »

Skipjack wrote:
Wed Dec 21, 2022 2:57 am
jrvz wrote:
Wed Dec 21, 2022 1:23 am
I saw one error in the animation at about 27:00 into the video, which seemed to show the two FRCs being formed with opposite polarity. They actually have to have current in the same direction, so after the collision they can form a single hotter FRC.
Actually both polarities will merge into a single FRC and opposite polarity seems to work better, from what I remember.
In an FRC, the current in the plasma is enough that the magnetic field within it (in the doughnut hole) is opposite the background field (see
https://en.wikipedia.org/wiki/Field-rev ... figuration). In Trenta, there's no cusp between the two FRCs, so the background field is in the same direction for both, so the internal field direction is the same for both, so the current direction is the same for both.

If you could arrange for oppositely polarized FRCs to collide, the result would have no net current loop. Maybe this led the animator to show a disorganized ball of plasma rather than an FRC after the collision.
- Jim Van Zandt


Skipjack
Posts: 6805
Joined: Sun Sep 28, 2008 2:29 pm

Re: Helion Energy to demonstrate net electricity production by 2024

Post by Skipjack »

usesbiggerwords wrote:
Fri Jan 13, 2023 8:31 pm
New video up:

https://www.youtube.com/watch?v=G1vyMcqiVtA
This is very similar to the presentation that David Kirtley gave at Princeton a few weeks ago. It is still great to hear him explain things again without interruptions though. Some things are a little clearer, others might actually be slightly less clear. It also looks like the Te:Ti = 0.1 plot is missing.

mvanwink5
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Location: N.C. Mountains

Re: Helion Energy to demonstrate net electricity production by 2024

Post by mvanwink5 »

Helion using a short pulse, avoiding ignition, using advanced (commercial) power electronics available only lately, has jumped ahead of their two FRC competitors (TAE, General Fusion) in terms of time to commercial prototype. It remains to be seen if Zap is able to succeed, but Helion is near term.

We can see with the sudden PR efforts of the Fusion teams that commercial Fusion is coming faster than the Utilities or politicians imagined. This PR is therefore necessary to avoid commercial shock (Utilities plan a decade ahead).
Counting the days to commercial fusion. It is not that long now.

Skipjack
Posts: 6805
Joined: Sun Sep 28, 2008 2:29 pm

Re: Helion Energy to demonstrate net electricity production by 2024

Post by Skipjack »

mvanwink5 wrote:
Fri Jan 13, 2023 9:58 pm
two FRC competitors (TAE, General Fusion)
Interestingly General Fusion switched from an FRC to a Tokamak. I assume that is because they only ever tested with injecting a single FRC- target that did not merge with another one. This makes things a lot harder because FRCs at low temperatures are rather unstable. Accelerating two of them and merging them forms a single, hotter and more stable FRC. It is why both Helion and TAE are doing this.

Skipjack
Posts: 6805
Joined: Sun Sep 28, 2008 2:29 pm

Re: Helion Energy to demonstrate net electricity production by 2024

Post by Skipjack »

jrvz wrote:
Fri Dec 23, 2022 5:17 pm
Skipjack wrote:
Wed Dec 21, 2022 2:57 am
jrvz wrote:
Wed Dec 21, 2022 1:23 am
I saw one error in the animation at about 27:00 into the video, which seemed to show the two FRCs being formed with opposite polarity. They actually have to have current in the same direction, so after the collision they can form a single hotter FRC.
Actually both polarities will merge into a single FRC and opposite polarity seems to work better, from what I remember.
In an FRC, the current in the plasma is enough that the magnetic field within it (in the doughnut hole) is opposite the background field (see
https://en.wikipedia.org/wiki/Field-rev ... figuration). In Trenta, there's no cusp between the two FRCs, so the background field is in the same direction for both, so the internal field direction is the same for both, so the current direction is the same for both.

If you could arrange for oppositely polarized FRCs to collide, the result would have no net current loop. Maybe this led the animator to show a disorganized ball of plasma rather than an FRC after the collision.
You were correct. I was wrong.
From David Kirtley's Twitter today:
"It does matter what the polarities are -and they are aligned in the same direction."

Carl White
Posts: 476
Joined: Mon Aug 24, 2009 10:44 pm

Re: Helion Energy to demonstrate net electricity production by 2024

Post by Carl White »

"The problems with Helion Energy"

https://www.youtube.com/watch?v=3vUPhsF ... ableMatter

In case anyone has the time and energy to post a rebuttal there. The top level (pinned) comment smears David Kirtley's honesty.

Skipjack
Posts: 6805
Joined: Sun Sep 28, 2008 2:29 pm

Re: Helion Energy to demonstrate net electricity production by 2024

Post by Skipjack »

Carl White wrote:
Sat Jan 21, 2023 12:16 am
"The problems with Helion Energy"

https://www.youtube.com/watch?v=3vUPhsF ... ableMatter

In case anyone has the time and energy to post a rebuttal there. The top level (pinned) comment smears David Kirtley's honesty.
I tried. It got deleted. Go figure.
That guy is a complete jerk.

mvanwink5
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Joined: Wed Jul 01, 2009 5:07 am
Location: N.C. Mountains

Re: Helion Energy to demonstrate net electricity production by 2024

Post by mvanwink5 »

Big money at stake.
Counting the days to commercial fusion. It is not that long now.

Skipjack
Posts: 6805
Joined: Sun Sep 28, 2008 2:29 pm

Re: Helion Energy to demonstrate net electricity production by 2024

Post by Skipjack »

He is trying to ride on the popularity of the Real Engineering video to get some view, I guess.

mvanwink5
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Location: N.C. Mountains

Re: Helion Energy to demonstrate net electricity production by 2024

Post by mvanwink5 »

Yes, could just be a Y-troll for cash. I never rule out outside $$ though. The fact he deleted your comment speaks to dishonesty.

The more I consider your point the more it could make sense, there were a huge number of views of the Helion video. It is a shame that mud thrown at a popular topic is a handy way to garner views.
Counting the days to commercial fusion. It is not that long now.

Giorgio
Posts: 3061
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Location: China, Italy

Re: Helion Energy to demonstrate net electricity production by 2024

Post by Giorgio »

Skipjack wrote:
Sat Jan 21, 2023 1:39 am
I tried. It got deleted. Go figure.
That guy is a complete jerk.
Not only him.
I also tried few times in the past to correct wrong information on video of other channels, but if you do not follow their narrative they just delete you.
It seems that this has become a standard procedure on youtube.

Just ignore them.
A society of dogmas is a dead society.

mvanwink5
Posts: 2143
Joined: Wed Jul 01, 2009 5:07 am
Location: N.C. Mountains

Re: Helion Energy to demonstrate net electricity production by 2024

Post by mvanwink5 »

Just ignore them.
Sound advice.
Counting the days to commercial fusion. It is not that long now.

Maui
Posts: 586
Joined: Wed Apr 09, 2008 12:10 am
Location: Madison, WI

Re: Helion Energy to demonstrate net electricity production by 2024

Post by Maui »

Skipjack wrote:
Sat Jan 21, 2023 1:39 am
Carl White wrote:
Sat Jan 21, 2023 12:16 am
"The problems with Helion Energy"

https://www.youtube.com/watch?v=3vUPhsF ... ableMatter

In case anyone has the time and energy to post a rebuttal there. The top level (pinned) comment smears David Kirtley's honesty.
I tried. It got deleted. Go figure.
That guy is a complete jerk.
As someone with only a casual understanding of the physics I'd love if someone were able to provide that rebuttal here.

Skipjack
Posts: 6805
Joined: Sun Sep 28, 2008 2:29 pm

Re: Helion Energy to demonstrate net electricity production by 2024

Post by Skipjack »

- Critique: "FRCs have been done before and never worked."
First, define "worked"! What was the goal of the experiment and what was the outcome?
Second, yes, FRCs have been done before and the members of Helion's founding team were actually involved with several of them. They applied the lessons learned from those to their own design, which they have tested over 6 prototypes so far.
Lessons learned and applied:
1. Size of the FRC. The larger, the less susceptible to n=2, rotational instabilities.
2. Elongation to radius ratio. The longer the FRC, the more stable it is to tilt instabilities.
3. The merging before the compression. This part creates a single, hotter and more stable FRC as a target for compression. FRCs get more stable, the hotter they are.
4. Helion's FRCs have a very low electron to ion temperature (Te:Ti) ratio of 0.1 and less. That makes things a lot easier compared to machines where both are in an equilibrium because:
P(fus)/P(loss) scales as Ti^1.5 / (Z^2 * Te^0.5 )
Where Z is the atomic number (in case you wonder about that).

- Critique: "Deuterium -Helium3 has a smaller reaction cross section than Deuterium- Deuterium. At the 100 million degrees temperature discussed in the video, Deuterium-Deuterium reactions would be much more likely than Deuterium-Helium3 reactions."

That is generally true, but the author misses some key points:
Trenta is a subscale prototype with much weaker magnets than what they are proposing for a full scale powerplant. Because of that temperatures are somewhat lower than in a full scale power plant. Power plants aim for temperatures 20 keV (220 million degrees) and up to 330 million degrees (30keV). At that point the D-He3 reactivity surpasses the D-D reactivity.
That said, Helion actually wants some D-D reactions because that is how they are breeding their He3.
D-D => He3 +n or D-D => T +p
Both reactions have a 50% chance of happening.
So, in mixed mode (breed and power) machines, they will need two D-D reactions for every D-He3 reaction, at least until the Tritium inventory is large enough that they have a constant supply from decay (Tritium beta decays into Helium3). Sicne Tritium has a half life of 12.3 years, that can take maybe 20 years. That fact is probably the best criticism of Helion's approach.

- Critique: "Deuterium- Helium3 is too hard and Tokamaks cannot do it. Therefore Helion's approach of fusing Deuterium and Helium3 can never work."
D-He3 is very hard to ignite, but they do not need ignition for their design to produce enough net electricity to be economic. Most of the energy from D-D and D-He3 reactions is released as charged particles, not in neutrons. Helion can recover the energy in charged particles directly as electricity at a higher efficiency than a steam plant would. They can also recover 95% of the input energy directly as electricity. That makes their machines a lot more efficient.
Further, FRCs are high Beta (~1.0) compared to Tokamaks (~0.05). Beta means the ratio of the plasmas internal pressure to the pressure applied externally via magnets. If it was just about the efficiency of the magnets (it is not), then a 10 Tesla Helion machine would outperform a 200 Tesla Tokamak.
But, it is a bit more complicated than that, because confinement times in FRCs are generally lower. You win some, you lose some. Overall it is still a win for Helion's approach.
Since Helion is using adiabatic heating through the compression stage, they can to some extent(!) balance temperature and density almost linearly for a given magnetic field. D-D reactions favor higher density and lower temperatures. D-He3 is the opposite way round. They can tune that just to the right sweet spot between density and temperature depending on which reaction they want more of.
Another thing that works in Helion's favor is the aforementioned Te:Ti ratio. This ratio actually decreases further with higher temperatures. So the hotter the plasma gets, the smaller that ratio. Trenta already showed Te:Ti at <0.1. It is likely that a power plant will have an even lower ratio. Lower electron temperatures greatly reduce Bremsstrahlung losses. At a ratio of 0.1, thermal transport losses actually kick in earlier than Bremsstrahlung.

- Critique: "The neutrons from Deuterium-Deuterium reactions would have fried Trenta and I see no shielding."

As mentioned, Trenta is a subscale prototype, an experiment. It is smaller, weaker and only operates at one pulse every 10 minutes (max). A full scale powerplant would do 10 pulses a second!
Not all shots were fueled by Deuterium or Deuterium + He3. Many were fueled by a mix of hydrogen and Deuterium or pure hydrogen, depending on what they wanted to test.
Because of that alone, the total neutron flux that Trenta has experienced so far is not that high.
What the critique does not mention is that neutrons from D-D reactions have a much lower energy than those from Deuterium- Tritium reactions (2.45 MeV vs 14 MeV). Those 2.45 MeV are below the activation energy of many materials.
The machine is mostly made from low activation materials or materials with a half life measured in minutes. Aluminum activated by D-D neutrons has a half life of 2 minutes.
In fact testing different materials under neutron exposure was one of the purposes of Trenta. They have tested quite a few alloys to see how they behave.
There is still permitted shielding of course. It is in the walls of the room and not close to the actual machine, which can handle the aforementioned relatively reduced neutron load just fine.
It is also worth mentioning that a mixed mode Helion power plant (that does both breeding and power production) would produce neutrons only in one third of all reactions. So the neutron flux, even for those machines would be lower than for a D-T Tokamak.

- Critique: "Helion claims that they discovered new physics when they say that the ion gyro radius is 25% larger."
The whole ion gyro- radius thing was based on a misunderstanding and out of context quote and maybe also bad wording.
What happened was that Trenta achieved a higher ion temperature than predicted by Helion's too conservative physics model (a higher ion temperature is actually a good thing!). That higher ion temperature caused a 25% increase in ion gyro radius, which is perfectly in line with established physics. That's it. Nothing to see here!

- Critique: "Helion had previously said that they would have a working power plant in 2021. "
IM was very eager to get a "gotcha" on Helion. I guess he did not read further up on the page, or he would have seen that Helion was in the process of raising funding at the time. Those of us here, who have been here for a while and were paying attention, will remember their funding problems until recently.
They did not get that funding until now. Even Trenta was less than 35 million (especially if you take the 35 million into 2019 dollars, when they started building it).

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