Helion Energy to demonstrate net electricity production by 2024

[Carl White]

Turbo pumps alone will not get you to UHV.

Can't turbomolecular pumps (TMPs; the label appears upside-down in the image) achieve 1.0e-11 torr though?

[Skipjack]

These tweets should give some more insights into their pumps:

HelionTurbopump02.JPG (68.98 KiB) Viewed 6039 times

Turbomolecular pumps like this one let us pump out all the air to 1E-8 Torr (1 Trillionth of an atm!). Rotating at 33,000 rpm, they pump Hydrogen (and Deuterium), operate at high temp, and support continuous fusion operation without regeneration (unlike Cryopumps).

https://twitter.com/Helion_Energy/statu ... NmUj-L5lwg

HelionTurbopump01.JPG (59.1 KiB) Viewed 6039 times

Turbo pumps also have a unique feature – the Drop. They operate most efficiently when the gas transitions from fluid flow to molecular flow (individual particles), dropping OoM in seconds. Watch it in action – top is foreline, bottom is chamber pressure.

Note that on twitter, the above is actually a video.
https://twitter.com/Helion_Energy/statu ... NmUj-L5lwg

Helion is still going to use turbomolecular pumps for Polaris.
They have high throughout, steady operating, compatible with tritium and high temperatures.
Cryo panels in contrast are much more difficult to engineer with, plus it’s where all the tritium lives.

[kurt9]

Usually a turbo pump is used with a cryo-trap to get down to UHV regime. I've never heard of a turbo pump getting down to UHV regime without the assistance of a cryo-trap.

The article mentions a 24 hour bake out period. My customers running MBE tools used a 3 day bake out cycle. They also used diffusion pumps as well. Granted this was 30 years ago and diffusion pumps are considered antiquated these days. However, diffusion pumps work, have no moving parts, and are much cheaper than turbo pumps. Their drawback is that you have to be careful to make sure they are closed off whenever the pressure rises into the regime where roughing pumps work or you will get the diffusion pump oil all over your chamber.

The advantage of turbo pumps is they do not use diffusion oil and do not have to be cleaned (usually once a year for a diffusion pump). However, they can be "crashed" if you allow too high of pressure into them while running. Its just like a jet engine when you have a bird strike.

[kurt9]

Turbopumps with cryo-traps can get down to 10-11 torr. This is the typical pressure used in MBE process.

MBE is a rather low throughput process to make certain opto-electronic chips. These guys make them.

https://www.riber.com/

The image you posted above just reminded me that cryo-traps do not work well with Hydrogen. Neither do diffusion pumps. Hydrogen is such a small molecule compared to other gases (O2, N2, Argon, etc.). Its a pain in the ass to work with really.

[Skipjack]

IIRC, Trenta runs at >= 1E-5 background pressures.

[usesbiggerwords]

I have first hand experience in the semiconductor industry with turbopumps pumping down to the uTorr range, regularly. No cryo-trap needed. Having a molecular mean-free path on the order of meters is necessary for transistor fabrication.

I've also seen what happens when the bearings fail. The blades weld themselves together just from the kinetic energy alone, and the whole 5 ton piece of processing equipment moved off it's base by a good foot. Good times.

[mvanwink5]

I had forgotten Helion's turbo pump development and the discussion about it. It is important. Helion has all the pieces.

[Munchausen]

Some film from 12:00 here

https://www.youtube.com/watch?v=Dp6W7g9no0w&t=712s

[mvanwink5]

The government researchers act ignorant of what is being done by Helion and General Fusion, and then they speak with such self confidence in their pessimism. What I find lacking is anything to back up the government researchers naysaying, anything that contradicts the published experimental results and published theoretical results of Helion and General Fusion.

This video fails to explore why the government researchers act with such pessimistic ignorance; could it be their multi deca-billion dollar, multi decade research contracts would be at risk of being defunded? That aspersion was not cast in the video, but there was the implication that Helion and General Fusion might be over promising to get funding.

Nothing new in that regards.

[usesbiggerwords]

This video fails to explore why the government researchers act with such pessimistic ignorance; could it be their multi deca-billion dollar, multi decade research contracts would be at risk of being defunded?

This is typical with government research in general, and not just in fusion. The self-licking ice cream cone metaphor is real for a reason.

[Skipjack]

Helion Machine Shop:
https://twitter.com/Helion_Energy/statu ... GCEHXHOjDQ

[mvanwink5]

This is about manufacturing, it is no longer about proving fusion is economical. Utility scale solar / batteries is obsolete, it is just not obvious to most. This is the age of dinosaurs, extinction is next.

[Skipjack]

AFAIK, the first task of the machine shop is to make components for Polaris.

[mvanwink5]

Yes, it looks like a machine tool for rather large components, which might help with lead time. 3 machines are planned, this being the first. I wonder if this is for machining diverters? On the other hand, that large wheel might be for winding large magnets; it does not look like a typical lathe?

It is exciting to see long lead time factory manufacturing equipment being delivered already.

[mvanwink5]

This is the machine:
https://www.haascnc.com/machines/vertic ... /vs-3.html
https://twitter.com/dekirtley/status/15 ... 0251293696
Not a lathe, but a computer controlled milling machine. Awesome!