LPP Fusion Will Scale to Higher Fusion Yield With New Beryllium Electrode

On June 4th, 2019 LPPFusion’s research team started a new series of experiments using for the first time beryllium electrodes in a plasma focus device.

If LPP Fusion development succeeds then they will be able to mass-produce 5 megawatt nuclear fusion reactors with aneutronic (aka low radiation) reactions and each device will be about the size of a small shed. They would fit in a regular ten foot by ten foot room and they would capture arcs of energy directly as electricity.

The price would be ten to twenty times less than coal or natural gas at half a cent per kilowatt-hour.

After 44 shots to date, they have achieved their first goal of firing with low impurities.

Fusion yield has risen 60-fold since the first shot and is now 1/10th of a joule. This is
comparable with the best results achieved with the similar 10-cm long tungsten anode, but not yet above our record of ¼ J, achieved in 2016 with a longer 14-cm anode. They have not yet seen the long-lived filaments that they hope to produce as a step to getting much higher fusion yield. That is their next goal.

The main reason for replacing their tungsten electrodes with beryllium ones was to reduce impurities in the plasma. The tungsten electrode formed a deep, fragile, tungsten oxide outer layer, that was easily vaporized, unlike pure tungsten metal. They expected beryllium would be far better in this respect, and they were right, as it formed a self-limiting oxide layer only 10 nm thick.

The initial goal of getting low impurity was reached but it looked different than expected. The electrode looked really dirty as it was totally covered in dark dust. They roughly measured the amount of dust on the vacuum chamber windows, using a spectrometer. They estimate the thickness at 25 nm. That does not sound like much, but it was 20 times more than they had expected.

Subsequent shots rapidly removed the dust or melted it into a smooth layer on the electrode and vacuum chamber. As more and more of the dust was removed, the impurities in the plasma decreased.

Yield rising

While the beryllium overall has a small impact on the plasma, remaining concentrations of beryllium dust still have a big impact on the symmetry of the current sheath, especially at the start of the shot. This lack of symmetry, they think, is limiting the compression in the pinch and thus the density needed to achieve high fusion yield.

They are seeing a steady rise in fusion yield as tests continue. The first measurable fusion yield was on shot 3, with only 1.6 mJ. By shot 7, they were at 20 mJ. They started altering the axial field coil current, which controls the amount of spin on the plasmoid, reaching 100 mJ on shot 43. By comparison, their record yield with FF-1 was 250 mJ, a quarter-J. Their first fusion yield goal with the beryllium is 1 J and they aim to reach 10 J by 200 shots.

They have achieved the first goal of the 2019 plan and might get to the 200 shot and 10 joule per shot level in another month.

The commercial goal is to generate 5 megawatts. 5 megawatt is 5 million joules per second. This would mean generate a net of 10 kilojoules per shot with 500 shots per second or generate a net of 50 kilojoules per shot with 100 shots per second.

The energy available in the pinch is proportional to the square of the current, so with a current of around 2.8 MA, instead of the present 1.1 MA, energy into the pinch could be increased to 80 kJ, which is almost 70% of the maximum energy that can be put into FF-1.

Written By Brian Wang, Nextbigfuture.com

26 thoughts on “LPP Fusion Will Scale to Higher Fusion Yield With New Beryllium Electrode”

  1. Ultimate plan is to harvest all forms of energy generated by Fusion e.g. photonics, kinetic (charged particles) and heat. Hoped for conversion ratio of 90%. No neutrons for decaborane fueled process makes this much easier, but it is harder to get Fusion temperatures for p boron reaction. Pinch magnetic field allows more heat absorption from electrons before they radiate off kinetic energy as X-rays. Learning which dials to turn to get consistent results is a tedious process. Right now
    a mixture of nitrogen and deuterium is being used to understand variables. Most needed now is $ for people and equipment upgrades.

  2. Question is: Can they do it? Can they make this system work and produce net energy? One would think the Chinese would fully fund this experiment.

  3. The fusion from the collapsing plasma “pinch” produces high energy charged alpha particles. These particles are ejected directionally down the axis of a conductive coil. The kinetic energy of the harged alpha particles is captured directly by producing current in the coil by induction.

  4. As long as they continue demonstrate progress then this going in the right direction. By the way, progress includes finding and fixing problems, even if the fix requires some backtracking, like changing to new anode and cathode materials. Note, I believe it was always their plan to go to beryllium but unforeseen problems (read the posting above about impurity problems) forced them to do so earlier than intended.

  5. Helium-3 could make the case for the R&D portion, while the business case would be based on the p+B11. The thing is that p+B11 is too difficult to do right off the bat, because the Coulomb barrier is too high. Meanwhile, D-T is too dangerous for a small laboratory like theirs, and it isn’t even aneutronic. Helium-3 is benign while having the lower Coulomb barrier and still being aneutronic.

    1. electricity (lots of it) goes in to hot decaborane gas, ionizes and makes plasma
    2. decaborane plasma forms a plasmoid, density goes up fusion occurs
    3. you get an electron beam going one way, ion beam going the other way
    4. electron beam needs to be captured and fed back in to the capacitors
    5. ion beam flies through coils, generates current that is fed back in to capacitors

    So step 4.

  6. The principle is largely already proven. DPFs aren’t really new devices. LPP contributions are largely in having a better understanding of how to control the fusion process and the realization that impurities are what lead to diminishing returns when pinch devices are scaled to extremely high current.

    Personally I wish that they had enough money and manpower to try D-T as I think they would do quite well. He3 is certainly an easier fuel but it can’t make the business case for investment because it is too rare and expensive.

  7. What they really need is proof of principle – proof of concept – proof of the basic science. If Helium-3 offers a lower bar to help them achieve this, then later on they can switch to p+B11 while optimizing the engineering and the economics. They haven’t even shown that their basic claim of a 4th-power scaling law works. Right now, it’s all about fussing over impurities.

  8. For R&D they are busy and don’t have time to swap fuels.

    For power production He3 is really quite rare and expensive. Boron is cheap.

  9. But their roadmap and milestones are pretty clear, and they seem to be well on their way. They need to improve by a couple of orders of magnitude to hit their next milestone. If they can do that, then that’s major progress.

  10. Now someone remark about how ‘plucky’ they are while being fully ‘transparent’ about their progress with a path towards fusion that other experts consider ‘not even wrong’.

  11. It seems that every one believe slow and steady is going to win the fusion race. I don’t believe penny pinchers will. This incremental process with take many years before you will know whether or not it will even work.

  12. The tungsten itself would vaporize and taint the plasma.

    Same happens for the Beryllium it is just that it doesn’t impact the plasma as much as W.

  13. My impression is that the tungsten impurities were coming from the oxide layer. If that’s the case, wouldn’t it be easier to eliminate oxygen sources in a production device with a tungsten electrode, then prime it by burning off any remaining oxide and flushing the chamber?

  14. Any exact timeline would be wrong, because this is new experimental science. Besides that, everything goes slower than expected for them, because they’re such a small team and so many engineering problems crop up. But this new device is the one they’ll use for the breakeven attempt. They’ll need to upgrade it to use boron fuel, and double the input power.

  15. That’s the goal, which is why I said “so far,” but they haven’t yet upgraded the reactor to borane. Right now they’re experimenting with deuterium.

    Fusion projects targeting D-T fuel use deuterium as well, because tritium is hard to handle, and unlike plain hydrogen, deuterium lets them count fusion neutrons.

  16. Im writing a patent on methods of removing the berrylium dust in the DPF reactor and making more symmetrical longer lived
    filaments. The method gives more control of the angular momuntum also. Im showing it to Eric Lerner.


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