Helion Energy to demonstrate net electricity production by 2024

[TallDave]

... but I think we can safely assume they hope to run D-He3 by the end of the year, since you can't convert D-T products to electricity via the virtual dynamo

Let's say that a certain machine can generate 1 MW burning D-He3 (at 20 keV); from that, 0.92 MW would be in ions. Switching to D-T it'd generate over 100 MW, and the fraction in ions would grow to 20+ MW.

So, if Helion's electromagnetic energy capture works, with D-T they'll have 20 times more to draw from than burning D-He3.

Is there a problem I'm not seeing?

Haha, yes that's true, I hadn't thought about that. You could capture the helium atom and its 3.5MeV, but as Skipjack notes the 14.1 MeV neutron would tend to melt the walls. Might be okay for a few pulses, though. I can see how that might be worth doing as a science experiment, if only to poke all the lab coat skeptics (who mostly work on toks) extra hard by getting net electricity from D-T about 50 years sooner than they will.

Still not sure just what the power output for D-T would be at the Te/Ti = .1 regime where Polaris operates though. Presumably it's better than D-D, but is it better than D-He3 at 20 keV? Couldn't say for sure.

[charliem]

Still not sure just what the power output for D-T would be at the Te/Ti = .1 regime where Polaris operates though. Presumably it's better than D-D, but is it better than D-He3 at 20 keV? Couldn't say for sure.

Well, unless some new weird phenomenon pop up in Polaris, power production from D-T at 20 keV is not going to just be higher than from D-He3, it is going to be overwhelmingly higher.

Tritium and Helium-3 have the same atomic mass, but Helium-3 has 2 electrons per atom and T only one.

So, we can expect a lower electron density using D-T (although not by much, 1.5 times at most) and ion densities slightly higher.

Losses (bremsstrahlung, transport and synchro/cyclotron) are mostly proportional to electron density. Less electron density, less losses. Again, not by much, the graph would hardly change from this.

Also, deuterium density will be a bit higher, and power production from D-D too.

The big difference comes from D-T reactions. Switching T for He3 would have a dramatic effect. As said, D-T is more than 100 times more reactive than D-He3 at 20 keV. That means that to represent D-T fusion power on that graph, we'd have to draw the line 2 orders of magnitud above that for D-He3.

I think Helion intends to do shots with D-T to build for themselves a bit of a cushion, in case the rest of the experiment doesn't work as expected.

Helion's initial designs did not use D-He3, but D-T. Look, for example, this 2014 version of their website: https://archive.is/CuaJz

The animation at the bottom depicts a machine that has the reaction chamber sorrounded a by big tank. This tank connects with something that looks like a heat exchanger, and this to a turbine.

That's a disposition suited for producing energy from neutrons.

[TallDave]

Still not sure just what the power output for D-T would be at the Te/Ti = .1 regime where Polaris operates though. Presumably it's better than D-D, but is it better than D-He3 at 20 keV? Couldn't say for sure.

Well, unless some new weird phenomenon pop up in Polaris, power production from D-T at 20 keV is not going to just be higher than from D-He3, it is going to be overwhelmingly higher.

Tritium and Helium-3 have the same atomic mass, but Helium-3 has 2 electrons per atom and T only one.

So, we can expect a lower electron density using D-T (although not by much, 1.5 times at most) and ion densities slightly higher.

Losses (bremsstrahlung, transport and synchro/cyclotron) are mostly proportional to electron density. Less electron density, less losses. Again, not by much, the graph would hardly change from this.

The big difference comes from D-T reactions. Switching T for He3 would have a dramatic effect. As said, D-T is more than 100 times more reactive than D-He3 at 20 keV. That means that to represent D-T fusion power on that graph, we'd have to draw the line 2 orders of magnitud above that for D-He3.

I think Helion intends to do shots with D-T to build for themselves a bit of a cushion, in case the rest of the experiment doesn't work as expected.

True as far as it goes, but here are a couple other factors to consider. For one, the power relationship between fuels does seem to change with both beta and Te/Ti, as well as temperatures. Note that D-He3 power peaks at higher temps than D-T.



Fuel ion heating by fusion products is the other factor that makes me hesitant to assume D-T vastly outpowers D-He3, at least at all machine temps (post-compression, pre-fusion). Since most of the D-T energy is in neutrons we might see less ion heating from D-T (a sort of "wet match" if you will) and consequently lower final plasma temps and lower power.

So for instance we might find that D-He3 is so efficient at self-heating that the average ion temps in a 12KeV FRC spike up to (say) 70KeV after fusion, but for D-T at 12keV machine power self-heating only pushes ion temps up to (say) 15kEV. I don't know that this is the case, but it might help explain why Helion is so optimistic about D-He3 -- Kirtley's paper calls out the need to remove energy from fusion products quickly before they can heat electrons.

One important note, in an ignited D–T (or D–He-3) plasma, particle heating primarily heats electrons (regardless of initial heating method), leading to the typically large electron to ion temperature ratios, and significantly increased radiation losses, further emphasizing the desire to remove energy directly from the fusion products prior to ignition or significant electron heating.

Of course, this is all handwaving, and it probably doesn't particularly matter, but it's fun to think through.

[charliem]

Interesting points.

Yep, lacking hard numbers, speculating over these machines workings can be fun.

Let's see if I can add something that makes sense.

The particles in a D-T plasma are electrons, deuterons, and tritons. In a D-He3 plasma they are electrons, deuterons, and helium-3 ions (helions). The first two are the same, the last one is not. Tritons and helions have equal atomic weights, but different charge.

I think this point of having the same weight is important, for the following:

Accelerating these particles to 300 km/s would impart on them these kinetic energies:

• Electrons - 0.0005 keV
• Deuterons - 1.88 keV
• Tritons - 2.81 keV
• Helions - 2.81 keV

From these numbers I take that most of the energy/temperature of the electrons (before final compression) comes from the initial process of creating the FRCs, while most of the energy/temperature of the ions comes from the acceleration (speed converted into heat).

Given this, I'd say it is reasonable to expect very similar Te/Ti ratios for both fuels before fusion start.

Also, there is this last graph you shared (my understanding is it comes from simulations by Helion). The situation it depicts, even with Te/Ti=1, is one where Qsci>10. If we add the supposition that Te/Ti would be more like 0.1 (not unreasonable, following the previous reasoning), then all those losses would be lower, resulting on an even higher Qsci.

Lastly, regarding electron heating. Remember that, even if by percentage it is much less burning D-T than burning D-He3, absolute power on charged particles is much higher in the former (20+ times more). This will increase losses, no doubt, but will also favor ignition (theoretically not needed in Helion's machines, anyway).

[Skipjack]

You guys are assuming that Helion would operate D-T experiments at power levels that would threaten the health of the machine. I think we can rule that out. Aside from fuel mix, they can also adjust a few other things to limit the amount of wall loading. One is magnetic field strength. The other is the ratio of density vs temperature. There are probably a few other things they can adjust on the fly, but it is late and my brain is not working right.

As for D-He3 vs D-T:

Helion was indeed planning to do D-T originally (even thought of a fusion- fission- hybrid as an intermediate step). Both were a pretty tough sell, though.
D-He3 produced protons should indeed impart a significant amount of heating to the plasma, though how much exactly remains to be seen.
At 14.7 MeV, they could make a significant difference. But, Helion has purposely not factored that into their calculations. So it is sort of a silent reserve that could help. Generally, Helion does not seem to want to do a steam plant (though plans might change if they decide to build D-D-T machines at some point). So, at least for now, the 3.52 MeV alphas produced by D-T would be the main source of recoverable energy. That said, D-T should still produce more net electricity in Polaris than D-He3, but the disadvantages for materials in particular make it tough to do so economically in a power plant.

[charliem]

You guys are assuming that Helion would operate D-T experiments at power levels that would threaten the health of the machine.

Hi Skipjack.

No, not really. I don't assume that. Just talking for the fun of it.

In fact, I'm quite sure Helion's personnel is smart enough to have envisioned this danger long ago (and any other we may imagine). They already know how to avoid it, and I think they are going be very conservative and cautious on their tests (by the way, add to your list of ways to limit power production, "diluting" the Tritium, doing a 1%-99% mix, for instance).

The idea I was trying to present is that doing a few shots with D-T is smart, because it is so much easier. Net electricity production in Polaris is expected to be marginal, at best. That implies that any minor snag could jeopardize it, and we all know how eager some people are to start screaming "scam, scan, scam...".

Trying D-T sounds to me as good insurance.

You know. Just in case.

[Skipjack]

Oh! I totally agree with that.
Oh yeah and the fuel mix ratio was indeed the other one, I was thinking of. Got distracted and then had completely lost my train of thought. Getting old, LOL
Anyway, they can do all that and probably get a decent performance with D-T out of it without doing too much damage.
We will see how it goes. Exciting times for sure!

[Skipjack]

New Helion News Letter is out:

HelionCableTray.jpeg (75.42 KiB) Viewed 11890 times

We always knew that 2024 would move quickly for all of us at Helion and the past few months have been no exception. Our production floor is bustling with activity as we push to finish building Polaris. Next door, in Ursa, Polaris itself is continuing to come together!

Compression section installation is underway

In April, we successfully installed the major support structures for Polaris' compression section. The final position requirements have extremely fine margins, and I’m so impressed with the team achieving an accuracy of less than 0.015”, which is challenging for a machine of this scale. With each support in place, we have been installing compression coils and are now far enough along to start testing the coils, as well as evaluating some of the diagnostics we will be using.

Cable trays are moving in

When we built Trenta, we spent more time hooking up cables than on anything else. For most of the machine, each was installed on a capacitor, dragged into place, then installed on the machine. Anyone who was at Helion for the Trenta cable install will attest to how long and tedious the process was. We’ve learned from it.

We’re now doing cable connections with modular cable tray units that can be assembled out of the racks, hundreds installed all at once, and quickly attached at each end. Over the past couple months, we’ve made major progress on tray fabrication and installation. We have no illusions about how time-consuming cable installation will still be, but we’re seeing that our new system is much faster, cleaner, and better than what we did on Trenta.

Control room goes live

Our control room is officially up and running. Our operators, engineers, and scientists have already been operating our formation tests from the control room for several months. In the last three months, we completed the monitoring and control connections, setting us up to remotely operate Polaris from our HQ building, Antares.

ADVANCE Act is passed into law

On July 9, President Joe Biden signed into law the Accelerating Deployment of Versatile, Advanced Nuclear for Clean Energy (ADVANCE) Act. The act does two things with respect to fusion: 1. It amends language in the Atomic Energy Act (AEA) of 1954 to classify fusion machines as particle accelerators, meaning fusion facilities can be regulated like hospitals and industrial facilities that use radioactive materials rather than nuclear fission reactors. And 2. It directs the NRC to study a design-specific license framework that would allow companies to site and operate facilities at different locations nationwide without the need for repetitive, site-by-site reviews. Both provisions should help significantly simplify the regulatory environment in which fusion energy companies operate.


This year alone, Helion has welcomed more than 90 new people to our team, all dedicated to ensuring we can bring fusion power to the world as soon as possible! As we grow, we are continuing to foster a culture founded on our core values. I am proud to see our 300+ member team continue to evolve as a mission-driven environment that still builds with the same urgency and rigor as our team did when we were building our first machine that achieved fusion, the Inductive Plasmoid Accelerator (IPA), over a decade ago.

Want to be part of our incredible growth and mission? See our current open positions!


David
Co-Founder & CEO

[TallDave]

As for D-He3 vs D-T:
So, at least for now, the 3.52 MeV alphas produced by D-T would be the main source of recoverable energy. That said, D-T should still produce more net electricity in Polaris than D-He3, but the disadvantages for materials in particular make it tough to do so economically in a power plant.

At sufficiently low temperatures that seems quite likely.

But keep in mind you'd need (first off) 5x as much D-T power to equal the electric output of D-He3, because you're losing 80% of the power to neutrons (D-He3 won't be totally aneutronic but Kirtley describes the difference as "orders of magnitude").

And besides the aforementioned ion heating upthread, the other reason I suspect the D-T and D-He3 electric outputs might converge at some higher temp machine conditions is Kirtley's warning about not letting fusion products heat electrons, as this moves us into high Te/Ti ratio regimes. Seems likely D-He3 is going to keep the Te/Ti ratio quite a lot lower than D-T once fusion begins, as we're harvesting the bulk of the fusion energy (as the charged products presumably whirl about the edges of the smoke ring, becoming ash that would eventually poison the reaction in a non-pulsed machine).

In some respects for this question we don't really care whether synchotron and brem losses increase for D-T, as long as we get a charged product to harvest, since we aren't trying to ignite the plasma anyway. But while the power given in the graph is instantaneous, for actual electricity production the fusion duration matters too. D-T seems likely to far more quickly raise electron temps to less friendly regimes. Although, since output doesn't seem to be affected, possibly this doesn't matter, or least not as much as D-He3's advantage in ion heating.



So a potentially shorter pulse of possibly less power. I think of this as the "D-T fizzle" scenario

But to be clear I still think they can get net electricity from a D-T pulse, just that there might be some regimes where D-He3 actually outperforms D-T.

Helion's FRCs are weird in that you're actually trying to avoid ignition, because an ignited plasma mainly heats the electrons.

[Skipjack]

David Kirtley is now commissioner at the newly established "Commission on the Scaling of Fusion Energy".

https://www.prnewswire.com/news-release ... 06152.html

[mvanwink5]

Any information as to when Polaris will be fully assembled & in service for operation?

[Skipjack]

Any information as to when Polaris will be fully assembled & in service for operation?

No firm numbers given by the company. I believe they are still aiming for the end of the year.

[mvanwink5]

Given their efforts to improve assembly, cabling prefab, in house capacitor manufacturing, quartz vessel manufacturing, I was hoping their project was ahead of schedule (they also reported logistics trouble was solved - not sure what they were - power semiconductor delivery?)

[crowberry]

To meet the goal of small scale net electricity production with Polaris during 2024 Helion Energy must of course have Polaris ready a reasonable time before the end of the year assuming there are no delays. I guess meeting this target that was set a few years ago is hard enough that Helion Energy has had to really make their best effort to keep up with their schedule. Anyway soon we will learn how things are going with Polaris.

[mvanwink5]

Since that target Helion learned their machine needed to be larger in diameter & they had some logistics issues (I believe unspecified), so their schedule shifted to full assembly in 2024 & early 2025 for net electric. I still am in hope for early news. LOL