Nuclear Fusion

Grey Havoc said:
hardware.slashdot.org

Government Scientists 'Approaching What is Required for Fusion' in Breakthrough Energy Research - Slashdot

Scientists hoping to harness nuclear fusion -- the same energy source that powers the Sun and other stars -- have confirmed that magnetic fields can enhance the energy output of their experiments, reports a new study. The results suggest that magnets may play a key role in the development of...
hardware.slashdot.org
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So this is hybrid laser-inertial and magnetic confinement combined.
 
Financial Times/ft.com article on the story (subscription or registration may be required):
Fusion energy breakthrough by US scientists boosts clean power hopes

https%3A%2F%2Fd6c748xw2pzm8.cloudfront.net%2Fprod%2F34be1380-7975-11ed-8784-df5ff10bb3cd-standard.png
 
I'm very sceptical of these reports because there's Qplasma and Qtotal. Equally, with lasers, it is not sufficient that the power out > power laser puts in, it must also be > the power put into the laser, since lasers have an efficiency too.

Then if power out > power driving laser, that only means the thermal power out > total driving power in, you now have to convert that thermal power to electricity, which means you lose 50% of it.
 
Is the 2.5MJ out thermal power or electrical power? Because if thermal, then the electrical output will likely only be 1.25MJ.
 
What Livermore Lab achieve is fantastic
They boosted there Light Laser into X-ray laser for Fusion

But it's long way for Laser Fusion Reactor
it has to burn constant fuel capsule.
means constant power up Laser banks ready to fire into Hohlraum
and after how many fusions of capsules the Golden Hohlraum has to be replaced ?
 
Michel Van said:
What Livermore Lab achieve is fantastic
They boosted there Light Laser into X-ray laser for Fusion

But it's long way for Laser Fusion Reactor
it has to burn constant fuel capsule.
means constant power up Laser banks ready to fire into Hohlraum
and after how many fusions of capsules the Golden Hohlraum has to be replaced ?
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I’ve always wondered how commercially possible this kind of fusion actually is compared to other forms of fusion.
 
Couldn't you arrange the pellets so that the detonation of one causes that of another, or have some kind of pellet injection method?

1670960485866.png
 
Flyaway said:
Michel Van said:
What Livermore Lab achieve is fantastic
They boosted there Light Laser into X-ray laser for Fusion

But it's long way for Laser Fusion Reactor
it has to burn constant fuel capsule.
means constant power up Laser banks ready to fire into Hohlraum
and after how many fusions of capsules the Golden Hohlraum has to be replaced ?
Click to expand...
I’ve always wondered how commercially possible this kind of fusion actually is compared to other forms of fusion.
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Frist, it works compare to other system with issues like Tokamak

Laser are not the problem, if you build enough Laser, you could operate the Reactor constantly
while one Laser recharge, another charge Laser fire into Hohlraum, while others are offline for maintain.
also issue with exchange of Hohlraum can be solve by Laser optics redirect the light into another Hohlraum
while "burn out unit" is exchanged

Stuff you can't do with Tokamak reactor, you have to shutdown entire thing, while Laser Fusion reactor works Modular.

But what now makes thing interesting is Laser Fusion Engine
It could bring Specific Impulse between 17000sec to 1000000sec
means you could reach Jupiter or Saturn in months, Mars in few weeks !
 
Michel Van said:
Frist, it works compare to other system with issues like Tokamak

Laser are not the problem, if you build enough Laser, you could operate the Reactor constantly
while one Laser recharge, another charge Laser fire into Hohlraum, while others are offline for maintain.
also issue with exchange of Hohlraum can be solve by Laser optics redirect the light into another Hohlraum
while "burn out unit" is exchanged

Stuff you can't do with Tokamak reactor, you have to shutdown entire thing, while Laser Fusion reactor works Modular.

But what now makes thing interesting is Laser Fusion Engine
It could bring Specific Impulse between 17000sec to 1000000sec
means you could reach Jupiter or Saturn in months, Mars in few weeks !
Click to expand...
Yup, Hyde fusion rocket. The impulse per pellet is given by:

(2 x pellet debris mass x Energy output)^0.5

Exhaust velocity is ~0.01c

Laser-fusion rocket for interplanetary propulsion (Conference) | OSTI.GOV

The U.S. Department of Energy's Office of Scientific and Technical Information
www.osti.gov www.osti.gov

Realistic Fusion Designs - Atomic Rockets

projectrho.com projectrho.com
 
Forest Green said:
Wonder how heavy the pellets are? A kg of hard black coal gives 25MJ/kg.
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The pellets are tiny, about 2-3mm in diameter (and made primarly of deuterium and tritium, so not heavy). We are not close to a working commercial plant yet, but we have proven it can work. There was a gap between the Wright Brothers first flight and commercial aviation, but now that its been proven to work, private companies are a lot more likely to get involved.
 
Nik said:
With respect, that Russian fission/fusion hybrid seems to have gone the way of China's 'Commercial Fusion Within Five Years' which, IIRC, would be needed to power the vast lift-pumps on the mega-N/S aqueducts.

Fusion laughs at 'Five Year Plans': IIRC, China now planning linear-ish solar & wind-farms along aqueducts to pick up the lack. Upside, local power-grids to pumping stations and near-by communities. Also, 'economies of scale'. Plus, pumping water with such vast canals to 'buffer' output is well-suited to 'wind/solar' mix. Down-side, those Chinese planners must be feeling very unhappy at how the universe has conspired to humble them, too....
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Humanity has been trying to confine a sun by means of magnetic fields for more than seventy years. Nature can only achieve it inside a star millions of times larger than a Tokamak. The zebra and the horse are very similar animals but one can be tamed and the other not. In my opinion this whole thing is a futile effort, based on faith, like the pyramids.
 
Michel Van said:
What Livermore Lab achieve is fantastic
They boosted there Light Laser into X-ray laser for Fusion

But it's long way for Laser Fusion Reactor
it has to burn constant fuel capsule.
Click to expand...
I regard the finding a curiosity at best-at worst a distraction away from building a device that can harvest constant fusion power right now-space-based power sats.
 
Dilandu said:
Forest Green said:
Is the 2.5MJ out thermal power or electrical power? Because if thermal, then the electrical output will likely only be 1.25MJ.
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Thermal.
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So really we need at least 5MJ out to have a chance of break even after conversion to electricity. I think heat exchange will be a real problem too. How do you transfer heat efficiently without melting things and/or cooling the plasma? I think Helion proposed a method that uses the fact that the expanding plasma caused by the fusion pulse pushes on a magnetic field to generate electricity directly.

www.helionenergy.com

Helion | Our technology

Helion is the first private company to reach 100 M°C plasma temperatures, a key milestone for generating electricity from fusion. Here's how.
www.helionenergy.com www.helionenergy.com
 
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" The zebra and the horse are very similar animals but one can be tamed and the other not."

{Cough} IIRC, not quite so binary: Google zebra carriage for multiple photos of eg Walter Rothschild and his single & 'four-in-hand' exploits around London. Seems he employed a 'superstar' horse-whisperer...
 
Forest Green said:
So really we need at least 5MJ out to have a chance of break even after conversion to electricity. I think heat exchange will be a real problem too. How do you transfer heat efficiently without melting things and/or cooling the plasma? I think Helion proposed a method that uses the fact that the expanding plasma caused by the fusion pulse pushes on a magnetic field to generate electricity directly.
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To be exact, you need a lot more, since the "input" here is the energy absorbed by fuel pellet. Lasers actually spend about two orders of magnitude more energy to deliver enough to pellet. If I recall correctly, the output of the fusion in this experiment was about 0,05% of energy spent.

So they managed to produce more energy from fusion, that were absorbed by the fuel. Which is tremendous achievment. But still quite far away from producing more energy that was totally spent.
 
publiusr said:
I regard the finding a curiosity at best-at worst a distraction away from building a device that can harvest constant fusion power right now-space-based power sats.
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SPS have own issue
Like launching tausend of tons hardware into Space to build Manhattan size solar collector in GEO
Biggest issue is transfer the energy of the SPS to Earth, too much losses
worst case scenarios in 1970s estimate only 12% of SPS Energy would comes out ground receiver...
 
Nik said:
" The zebra and the horse are very similar animals but one can be tamed and the other not."

{Cough} IIRC, not quite so binary: Google zebra carriage for multiple photos of eg Walter Rothschild and his single & 'four-in-hand' exploits around London. Seems he employed a 'superstar' horse-whisperer...
Click to expand...
Usually they paint a horse black and white for those kind of events. Pretty sure it's illegal to use an actual Zebra in fact.
 
I don't understand the obsession with nuclear fusion, there are other alternatives (e.g. molten salt Thorium reactors) which could deliver the same quasi unlimited energy with very little radioactive waste. Unlike the fusion reactors these concepts allready work and deliver energy.

Even if a fusion reactor might one day produce electricity I don't see any evidence that this would be cheap energy. These reactors will be extremly complicate to manufacture and operate, many parts have to cope extreme temperatures and will be checked/replaced periodically and will propably also become radioactive.

To me, fusion reactors are the Wankel engines amog the nuclear power plants, they look good on paper but not in the real world...
 
Dilandu said:
Well, if we could use Lunar materials - like silicon and aluminum - the cost would significantly drop down.
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That would work
but now you have launching tausend of tons hardware to the Moon to build factories and linear launch gun.

I wonder if it's cheaper to get near earth Asteroids and use them as building material for SPS
it would easier to move the building parts to Earth GEO, it would take little more time.
 
Michel Van said:
That would work
but now you have launching tausend of tons hardware to the Moon to build factories and linear launch gun.
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Not nessesary. We could use chemical approach. Lunar soil contains a lot of aluminum oxides. By using the free solar energy (solar furnace), they could be by various processes reduced to aluminum and oxygen. Which is basically two components of not-very-efficient, but free rocket fuel. So, we could send a chemical processing station on Moon, that would slowly but steadily crunch the regolith into materials for solar panels and fuel components for chemical "shuttle" that would arrive, load the cargo, took the fuel and boost it on low Earth orbit.
 
Nicknick said:
I don't understand the obsession with nuclear fusion, there are other alternatives (e.g. molten salt Thorium reactors) which could deliver the same quasi unlimited energy with very little radioactive waste. Unlike the fusion reactors these concepts allready work and deliver energy.
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People are still researching those, but nobody has succeeded in solving the waste issues they do have.

www.theguardian.com

Don't believe the spin on thorium being a greener nuclear option

Ecologist: It produces less radioactive waste and more power but it remains unproven on a commercial scale
www.theguardian.com www.theguardian.com

Thorium cannot in itself power a reactor; unlike natural uranium, it does not contain enough fissile material to initiate a nuclear chain reaction. As a result it must first be bombarded with neutrons to produce the highly radioactive isotope uranium-233 – 'so these are really U-233 reactors,' says Karamoskos.

This isotope is more hazardous than the U-235 used in conventional reactors, he adds, because it produces U-232 as a side effect (half life: 160,000 years), on top of familiar fission by-products such as technetium-99 (half life: up to 300,000 years) and iodine-129 (half life: 15.7 million years).Add in actinides such as protactinium-231 (half life: 33,000 years) and it soon becomes apparent that thorium's superficial cleanliness will still depend on digging some pretty deep holes to bury the highly radioactive waste.
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theconversation.com

Nuclear power: Why molten salt reactors are problematic and Canada investing in them is a waste

Molten salt reactors are being touted as an advanced technology for the production of nuclear energy, but their implementation is fraught with challenges.
theconversation.com theconversation.com

Another basic problem with MSRs is that the materials used to manufacture the various reactor components will be exposed to hot salts that are chemically corrosive, while being bombarded by radioactive particles. So far, there is no material that can perform satisfactorily in such an environment.
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Forest Green said:
People are still researching those, but nobody has succeeded in solving the waste issues they do have.
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Well, Rosatom actually made research on the hybrid fusion-fission reactor (which would use Tokamak-type device to produce fusion plasma, that would bombard the thorium fuel with neutrons - thus "burning out" the Th-232 and resulting U-233 by intence neutron radiation. Boosted-fission reactor, sort of. Currently it's still a theory, but, well, Rosatom is a world leader in advanced reactors. They are the guys who are most likely to figure it out.
 

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