Spherical Tokamaks

[Giorgio]

More proof (if needed) that private sector works an order of magnitude faster than government.

[paperburn1]

And cheaper as well, Just happened in my building, after the hurricane we lost the roof. After installing the new roof they were to put in drywall and the question was to drywall the ceiling or leave it bare like the other high bay and just paint it black. cost saving of 10,000 dolors to paint it black. Had to go back to navair for a decision and 8 months later they decided to drywall it, meanwhile they spent 40 thousand dollars in rental for all the scaffolding and staging waiting for a decision on to save ten grand or not.

[crowberry]

There is a new initiative on spherical tokamaks in the UK: https://www.gov.uk/government/news/next-step-in-fusion.

[Carl White]

UK hatches plan to build world's first fusion power plant

Nuclear scientists are designing an ambitious prototype facility that could demonstrate commercial energy production by 2040.

The British government announced a £200-million (US$248-million) investment on 3 October.

So more funding than the £20 million announced earlier for a first year.

Over the next four years, scientists at the Culham Centre for Fusion Energy near Oxford will produce a detailed design for the Spherical Tokamak for Energy Production (STEP)

https://www.nature.com/articles/d41586- ... HtqPFLXkRQ

[Skipjack]

It seems like companies like TE like this effort. It leaves a lot of room for private 3rd party contributors. I believe that TE would be a good candidate for that. Wasn't there another ST startup in the UK?

[Carl White]

Wasn't there another ST startup in the UK?

I haven't heard of another one. There's FIrst Light Fusion but they're trying inertial confinement.

[Skipjack]

Wasn't there another ST startup in the UK?

I haven't heard of another one. There's FIrst Light Fusion but they're trying inertial confinement.

Yeah, I know the FLF guys. Not sure how valid their idea is, but I think it is good that people pursue and invest in other approaches.
And I just remembered the other ST company in the UK: Applied Fusion Systems.
Quite frankly, I am a bit puzzled why AFS is doing their own ST, when the guy behind it could have just as well invested his money in TE, with a higher chance of success:
https://www.bbc.com/future/article/2017 ... on-reactor

[Carl White]

MAST UPGRADE

Officials at the Culham Centre for Fusion Energy (CCFE) in Oxfordshire have announced that they have achieved “first plasma” on the upgraded Mega Amp Spherical Tokamak (MAST). Following seven year of upgrade work on MAST at a cost of £55m, the machine was fully powered up for the first time yesterday allowing the experimental programme to begin.

https://physicsworld.com/a/first-plasma ... l-tokamak/

The MAST tokamak was operational between 1999 and 2013 before being shut down for the upgrade, which was completed last year. Known as MAST-U, it is expected to be able to create a plasma of deuterium with a timespan of around 2–4 s, compared with just 0.5 s before. A major feature of the upgrade is a new exhaust system – known as a divertor – that will aim to show that the tokamak is able to handle the intense exhaust heat emerging from the plasma more effectively than existing designs, including that used on ITER. The MAST-U divertor will aim to take a 50 MW/m2 heat load and reduce it to just 5 MW/m2.

Note: despite the name, it's essentially a new machine.

[Munchausen]

Fresh article on sperical tokamaks:

https://iopscience.iop.org/article/10.1 ... 587/abcdfc

"We find that for similar values of field and fusion power, but smaller volume, STs can have nTτΕ up to a factor of three higher and Qfus an order of magnitude higher than CTs."

"Potentially our results open an alternative and faster route to fusion power based on relatively small, low power STs."

[Skipjack]

That sounds very encouraging. Seems like Tokamam Energy made the right choice going for a Spherical Tomakak instead of a regular shaped one like Commonwealth does.

[Giorgio]

"We find that for similar values of field and fusion power, but smaller volume, STs can have nTτΕ up to a factor of three higher and Qfus an order of magnitude higher than CTs."

"Potentially our results open an alternative and faster route to fusion power based on relatively small, low power STs."

I don't want to cool down the excitement, but is worth mentioning that these are not experimental results but numerical simulations based on a specific physic model.
Also important to say that until a proper material/technology will be devised to manage the proposed heat flux for the first wall and the divertor, it will be tough to build a prototype to test the results of this math model (same power in smaller volume=higher heat flux on the surface).

[Skipjack]

I agree with that, but it shows that there is a path forward to do this IF engineering challenges can be resolved.
Clearly there is a lower limit to the how small it can get, but it is still better than that ITER monstrosity, likely even better than ARC.

[Munchausen]

"We find that for similar values of field and fusion power, but smaller volume, STs can have nTτΕ up to a factor of three higher and Qfus an order of magnitude higher than CTs."

"Potentially our results open an alternative and faster route to fusion power based on relatively small, low power STs."

I don't want to cool down the excitement, but is worth mentioning that these are not experimental results but numerical simulations based on a specific physic model.
Also important to say that until a proper material/technology will be devised to manage the proposed heat flux for the first wall and the divertor, it will be tough to build a prototype to test the results of this math model (same power in smaller volume=higher heat flux on the surface).

Better performance is always benificial. One way or the other.

For example:

If the tokamak finally becomes technology that produces energy, not interesting plasma physics, the scaling up and roll out will be accompanied with resource issues concerning rare earth metals for superconducting tapes. With better plasma performance MgB2 superconductors might be acceptable as a cheaper and more available alternative.

If it could be run D-D all the trithium breeding hassle could be avoided

[Giorgio]

I agree with that, but it shows that there is a path forward to do this IF engineering challenges can be resolved.
Clearly there is a lower limit to the how small it can get, but it is still better than that ITER monstrosity, likely even better than ARC.

Of course I fully agree. My concerns are mainly on the stability of their model once it will transposed into an actual physical setup.
Way too many times we have seen beautiful mathematical models succumb to tiny unaccounted natural phenomena when implemented in real experiments.

I see ITER as the equivalent of the SLS in the modern space race.
By the time it will be finally completed and running, people will be already using something cheaper, faster and more efficient, to the point that no one will really care about it anymore.

[Giorgio]

Better performance is always benificial. One way or the other.

Absolutely true.
I was just pointing out that those are not data from a real machine for now but just the results of a numerical simulation, with all the limits and pitfalls of simulations.