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Nuclear Fusion

Flyaway

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AI will help solve problems with nuclear fusion or so at least the US Federal government seems to believe.


The world’s largest nuclear fusion project began its five-year assembly phase on Tuesday in southern France, with the first ultra-hot plasma expected to be generated in late 2025.

The €20bn (£18.2bn) Iter project will replicate the reactions that power the sun and is intended to demonstrate fusion power can be generated on a commercial scale. Nuclear fusion promises clean, unlimited power but, despite 60 years of research, it has yet to overcome the technical challenges of harnessing such extreme amounts of energy.


And on a different tack.

 

uk 75

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1965 was an eventful year (my beloved TSR2 got canned) but it also marked the opening near my home town of Oxford of another futuristic project.
Reading this, it seems another of my lost futures along with Syd Mead's cars and the Boeing SST.
 

Flyaway

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Researchers find unexpected electrical current that could stabilize fusion reactions

Electric current is everywhere, from powering homes to controlling the plasma (link is external) that fuels fusion (link is external) reactions to possibly giving rise to vast cosmic magnetic fields. Now, scientists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) have found that electrical currents can form in ways not known before. The novel findings could give researchers greater ability to bring the fusion energy that drives the sun and stars to Earth.


Related journal article:

 

Grey Havoc

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This could prove to be quite useful indeed.
 

TomcatViP

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It reminds me:
As of today, about five years since Lockheed's public revelation of the cold fusion project, Lockheed is working on its "T4B" test reactor. That sounds pretty good -- about halfway through a 10-year project, you'd probably expect Lockheed to be on test reactor four or five right about now.

But here's the (other) thing: According to AW, Lockheed's T4 reactor was actually tested "in 2014-2015" -- in other words, the year Lockheed initially unveiled the project, it was already on its fourth iteration of the test reactor.
 
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Zoo Tycoon

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So how does this “we’ll have it sorted in five year” plan deal with neutron embrittlement of the highly loaded reactor structure? This is a fundamental problem with all the Tokamak schemes. It means that even if a demonstration was successful of say sustained net energy output for the easiest D/T fusion reactions a multi billion dollar power plant would have a safe operational life of just a few years.... hopelessly uneconomic. A while back there was talk of switching to the He3/T reaction because it has lower neutron flux...... all we need to do is mine the closest source of bulk He3 .....that’ll be the moon.

I‘m similarly skeptical about SPARC’s claims due to my memories of reading fusion articles/plan in the late eighties claiming it would be cracked within a decade because they knew enough to do it;- I suspect 40 years after these claims still no one does.

Still best of luck to em.
 

sferrin

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Stupid question here but couldn't you just put neutron absorption tiles (or reflectors) between the plasma and the structural portion of the tokamak?
 

Zoo Tycoon

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The problem is Fusion produces fast neutron which are difficult to effectively absorb. Here’s an explanation;-


This is also a problem for fission reactors as well which can be solved by running a continuous temperature profile which repeatedly anneals the pressure vessel steel, thus softening back to its design state. The problem with doing this in a fusion reactor is a lot of the highly loads structural parts within the neutron flux are not at the sorts of temperatures that anneal.
 
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Flyaway

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Well the Sun is a fusion reactor.;)


Experimental evidence of neutrinos produced in the CNO fusion cycle in the Sun

Abstract
For most of their existence, stars are fuelled by the fusion of hydrogen into helium. Fusion proceeds via two processes that are well understood theoretically: the proton–proton (pp) chain and the carbon–nitrogen–oxygen (CNO) cycle1,2. Neutrinos that are emitted along such fusion processes in the solar core are the only direct probe of the deep interior of the Sun. A complete spectroscopic study of neutrinos from the pp chain, which produces about 99 per cent of the solar energy, has been performed previously3; however, there has been no reported experimental evidence of the CNO cycle. Here we report the direct observation, with a high statistical significance, of neutrinos produced in the CNO cycle in the Sun. This experimental evidence was obtained using the highly radiopure, large-volume, liquid-scintillator detector of Borexino, an experiment located at the underground Laboratori Nazionali del Gran Sasso in Italy. The main experimental challenge was to identify the excess signal—only a few counts per day above the background per 100 tonnes of target—that is attributed to interactions of the CNO neutrinos. Advances in the thermal stabilization of the detector over the last five years enabled us to develop a method to constrain the rate of bismuth-210 contaminating the scintillator. In the CNO cycle, the fusion of hydrogen is catalysed by carbon, nitrogen and oxygen, and so its rate—as well as the flux of emitted CNO neutrinos—depends directly on the abundance of these elements in the solar core. This result therefore paves the way towards a direct measurement of the solar metallicity using CNO neutrinos. Our findings quantify the relative contribution of CNO fusion in the Sun to be of the order of 1 per cent; however, in massive stars, this is the dominant process of energy production. This work provides experimental evidence of the primary mechanism for the stellar conversion of hydrogen into helium in the Universe.


 

Flyaway

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Related paper:

The advanced tokamak path to a compact net electric fusion pilot plant

Abstract
Physics-based simulations project a compact net electric fusion pilot plant with a nuclear testing mission is possible at modest scale based on the advanced tokamak concept, and identify key parameters for its optimization. These utilize a new integrated 1.5D core-edge approach for whole device modeling to predict performance by self-consistently applying transport, pedestal and current drive models to converge fully non-inductive stationary solutions, predicting profiles and energy confinement for a given density. This physics-based approach leads to new insights and understanding of reactor optimization. In particular, the levering role of high plasma density is identified, which raises fusion performance and self-driven 'bootstrap currents', to reduce current drive demands and enable high pressure with net electricity at a compact scale. Solutions at 6–7 T, ~4 m radius and 200 MW net electricity are identified with margins and trade-offs possible between parameters. Current drive comes from neutral beam and ultra-high harmonic (helicon) fast wave, though other advanced approaches are not ruled out. The resulting low recirculating power in a double null configuration leads to a divertor heat flux challenge that is comparable to ITER, though reactor solutions may require more dissipation. Strong H-mode access (x2 margin over L–H transition scalings) and ITER-like heat fluxes are maintained with ~20%–60% core radiation, though effects on confinement need further analysis. Neutron wall loadings appear tolerable. The approach would benefit from high temperature superconductors, as higher fields would increase performance margins while potential for demountability may facilitate nuclear testing. However, solutions are possible with conventional superconductors. An advanced load sharing and reactive bucking approach in the device centerpost region provides improved mechanical stress handling. The prospect of an affordable test device which could close the loop on net-electric production and conduct essential nuclear materials and breeding research is compelling, motivating research to validate the techniques and models employed here.

 

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This was surprising news to me, the UKAEA is drawing up nominations for a potential site for a STEP (Spherical Tokamak for Energy Production) fusion reactor for operation from 2040.
Kind of exciting to think the world's first fusion power station could be on my doorstep, but I wasn't aware fusion experiments had got that far to start thinking about building a prototype station in the next decade.

https://www.lancasterguardian.co.uk...tion-in-heysham-takes-one-step-closer-3270292

Edit: link fixed
 
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Flyaway

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This was surprising news to me, the UKAEA is drawing up nominations for a potential site for a STEP (Spherical Tokamak for Energy Production) fusion reactor for operation from 2040.
Kind of exciting to think the world's first fusion power station could be on my doorstep, but I wasn't aware fusion experiments had got that far to start thinking about building a prototype station in the next decade.

https://www.lancasterguardian.co.uk/news/uk-news/proposal-to-build-worlds-first-fusion-power-station-in-heysham-takes-one-step-closer-3270292?fbclid=IwAR3r6SJb2iVBEI3lq51-a871P3v-Q1SSGrhwboLtrVqkr2rnhbdYFPEIFHk
I can’t get that link to open for some reason it says it cannot be found?

I did find this.

 

Grey Havoc

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Yes, original link seems to be down at the moment.
It is back up now.
 
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