General Fusion in the news

[crowberry]

My guess and speculation is that the fancy architecture of the Fusion Demonstration Plant became too expensive as a next step in terms of the available funding for General Fusion, so LM26 was created to target a bit scaled down results with less money required. This plan has clearly been welcomed by the investors as General Fusion received new funding.

[choff]

Been awhile since I last posted. Went to check google map for a restaurant location for a birthday lunch, and low and behold, General Fusion has practically moved right into my back yard, 4 km, 8 minutes away. Right in the same business park with the hobby store I buy my comic books at.

[choff]

Been awhile since I last posted. Went to check google map for a restaurant location for a birthday lunch, and low and behold, General Fusion has practically moved right into my back yard, 4 km, 8 minutes away. Right in the same business park with the hobby store I buy my comic books at.

[mvanwink5]

Huge announcement by General Fusion. Their last hurdle was a proven liquid metal wall compression chamber for their plasma.
https://mailchi.mp/generalfusion/publis ... c2986861e1

[crowberry]

General Fusion has written in detail on the status and plans for LM26 at https://generalfusion.com/post/innovati ... ft-launch/.

[mvanwink5]

LM-26 was mentioned in their January 11, 2024 news letter, but I had no idea what it was and this latest publication (TY Crowberry) illuminates that.

In abbreviated review (my understanding), GF has followed a fusion path of concept (mechanical compression of plasma using steam pistons and a spinning liquid metal chamber), to building and testing the device components in parts. De-risking a costly project has been their constraint as it is for all private fusion projects. The point of a de-risked (financial) is to build near full scale devices step wise to develop & justify the next more expensive step.

Breaking the component parts into projects:
The mechanical compressor steam pistons were designed, built tested at full scale for speed and timing.

The spinning liquid metal chamber was more difficult due to dynamic turbulence at the chamber surface that would result in contaminating the plasma during the piston driven shock compression. A process of testing, modeling, concept reformulation, finally resulted in their latest design, scaled build, and successful test. This was the project hold up.

Plasma injector design took years and required first determining the topological plasmoid that could be adiabatically compressed to fusion conditions, then building the near full scale injector to produce that exact plasmoid.

LM-26 is a full scale throwback to their earliest plasma compression testing which at the beginning used explosives to compress a small scale plasma chamber, except now LM-26 goal is to use a full scale lithium cylinder and high powered magnetic coils to collapse the lithium cylinder. This test is a step wise de-risk effort to prove plasma compression will meet fusion conditions on their injected plasma. This simplified compression method using a solid lithium chamber, magnetically compressed, seems to be the last financial de-risk hurdle before proceeding to the assembled near commercial prototype which will use a mechanically compressed spinning liquid metal chamber.

First step in LM-26 is their smaller scale 'prototype stage 0', designed & built in less than a year, and it looks like it has satisfied GF, so they are now proceeding to their next step, a full scale of their simplified compression system (solid metal chamber, magnetically compressed by their Theta Coils). Time line for the full scale testing of LM-26 is for it to be complete by 2026.

To be clear, commercial machine will not use magnetic compression so there is that step going from solid lithium ring compressed by magnetic coils to a liquid metal ring compressed by pistons, but LM-26 is intended to accelerate GF's progress by proving full scale plasma compression.

[mvanwink5]

Latest GF update, this one on their computer code for hydrodynamics, to be used on their liquid metal liner design.

https://mailchi.mp/generalfusion/peer-r ... c2986861e1
Excerpts:

The code, introduced in a new paper in Physics of Fluids, helps General Fusion to rapidly model its game-changing liquid metal liner in a commercial machine. General Fusion completes simulations in a minute on a single computer that otherwise would take hours or weeks.
*****
the validated code predicts the motion of General Fusion’s proprietary liquid metal liner as it is mechanically compressed by an array of pistons. As the company optimizes the power plant configuration, it uses the code to understand the performance of the liner in a commercial machine. General Fusion’s MTF approach to compressing liquid metal around the plasma to create fusion energy is unique in the world. It is the only fusion technology that addresses the major barriers to commercialization, including material degradation, fuel production, energy capture, and cost barriers.
*****
General Fusion’s new MTF demonstration, LM26, is designed to reach fusion conditions of over 100 million degrees Celsius by 2025. It will progress towards scientific breakeven equivalent by 2026.

[crowberry]

General Fusion has described in detail their plans for LM26 and their preceeding steps: https://generalfusion.com/post/charting ... with-lm26/.

[mvanwink5]

Launched in the Fall of 2023, our P0 testbed uses magnetic force to compress a solid lithium tube. It’s a small-scale version of the LM26 compression system and provides critical data, significantly de-risking LM26.

GM is forming plasma and compressing the plasma partially in their full size plasma device termed PI3. Then, GM injects the plasma into a solid metal lithium test chamber, a machined lithium tube, for further adiabatic compression of the plasma to fusion conditions. This test chamber that the plasma is injected into is a solid lithium tube, and plasma compression is performed by magnetically collapsing the lithium tube. Collapsing the solid lithium metal tube magnetically is intended to simulate compression operation cycle of their spinning liquid lithium metal mechanical compressor, called LM26.

A lot of work, but GM is doing everything possible to de-risk the big investment into a full scale plasma mechanical compressor, called LM26, that compresses plasma to fusion conditions.

PS: Originally General Fusion used explosives to compress an aluminum tube to adiabatically compress plasma to get their test data. The tokamak toroidal geometry was finally determined through these early experiments to enable adiabatic compression to fusion conditions. Now they are using magnetic compression instead of explosives (a bit more expensive I imagine).

[crowberry]

General Fusion has issued a new press release: New third-party analyses support General Fusion’s MTF technology path to commercialization, which is worth reading:

To assess General Fusion’s TBR, the UKAEA conducted modelling with simplified spherical parameters representative of the company’s commercial MTF concept and calculated advantageous tritium breeding ratios greater than 1.5. For comparison, a power plant requires a minimum TBR of 1.1 to ensure it will breed sufficient fuel for the life of its operations.

SRNL’s study found that the design requires less tritium for start-up, has a significantly lower doubling time, and has a higher tritium breeding ratio than what is publicly available for traditional tokamak fusion approaches.

The UKAEA’s modelling also supports General Fusion’s plasma compression approach using a liquid metal wall—the game-changer in General Fusion’s power plant design—to shield the vessel from neutron activation.

The company is accelerating its progress by building a fusion demonstration called Lawson Machine 26 (LM26) to achieve technical breakthroughs that will de-risk and fast-track the path to a power plant. LM26 is designed to achieve fusion conditions of over 100 million degrees Celsius by 2025 and scientific breakeven equivalent by 2026.

https://generalfusion.com/post/new-thir ... alization/

[crowberry]

General Fusion has announced that:

The fusion vessel for LM26 is here!
A core component of our groundbreaking fusion demonstration machine, it houses the lithium liner that will compress plasmas to transformative technical milestones for fusion energy—1 keV, 10 keV, and ultimately scientific breakeven equivalent.

Sub-scale testing is complete. Our capacitor banks are ready. Lab operations are going full tilt to begin compressing plasmas at full scale in early 2025—stay tuned!

[mvanwink5]

In other words, GM says everything is going as planned with their program:

https://iopscience.iop.org/article/10.1 ... 326/ad9033

Measurement of spherical tokamak plasma compression in the PCS-16 magnetized target fusion experiment

A sequence of magnetized target fusion (MTF) devices built by General Fusion have compressed magnetically confined deuterium plasmas inside imploding aluminum liners.

Here we describe the best-performing compression experiment, PCS-16, which was the fifth of the most recent experiments that compressed a spherical tokamak plasma configuration. In PCS-16 the plasma remained axisymmetric with δBpol/Bpol < 20% to a high radial compression factor (CR > with significant poloidal flux conservation (77% up to CR =1.7, and ≈ 30% up to CR = 8.65) and a total compression time of 167 μs. Magnetic energy of the plasma increased from 0.96 kJ poloidal and 17 kJ toroidal to a peak of 1.14 kJ poloidal and 29.9 kJ toroidal during the compression, while thermal energy was in the range of 350 ± 25 J. Plasma equilibrium was a low-β state with βtor ≈ 4% and βpol ≈ 15%. Ingress of impurities from the lithium coated aluminum wall was not a dominant effect. Neutron yield from D-D fusion increased significantly during compression.

Thermodynamics during the early phase of compression (CR < 1.7) were consistent with increasing Ohmic heating of the electrons due to a geometric rise in the current density at near-constant resistivity, and with increasing ion cooling that approximately matched ion compression heating power. Ion cooling by electrons was significant because the electrons were much cooler than the ions (Te = 200 eV, Ti = 600 eV).

Magnetohydrodynamic simulation was used to model the emergence of instabilities that increased electron thermal transport in the final phase of compression. Conditions for ideal stability were actively maintained during compression through a current ramp applied to the central shaft, and after this current ramp reached its peak two-thirds of the way through compression we measured a transition in plasma behavior across multiple diagnostics.

[crowberry]

General Fusion has completed the assembly of the LM26 device. The status of the project and the plans for it are described in this detailed and long post at https://generalfusion.com/post/building ... -complete/.

[Skipjack]

5 to 10 ms confinement is pretty long for a plasmoid like that. Suprised by that a bit.

[crowberry]

General Fusion has created the first plasma in LM26 and they are by now forming plasmas daily in LM26.

https://generalfusion.com/post/general- ... n-machine/