Review of General Fusion's Machine.

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Review of General Fusion's Machine.

Postby ThePolywellGuy » June 1st, 2014, 9:08 pm

Hi All,

I am a fusion blogger - I have been since 2009. I hold a PhD in Engineering from a Major University and have 7+ years of Fusion experience.

This is my blog on the Polywell. The Polywell is an idea for a fusion reactor, based on the fusor.

Normally, I keep my posts secret. However, I thought I would open up a draft for the Hack-A-Day community. (Still a work in progress) (Feedback Welcome)

I am covering General Fusion. and the Northwest Nuclear Consortium in my next post.

The Polywell Guy



On March seventeenth, General Fusion spoke at TED largest conference [46]. You can watch the talk here. Its founder, Michel Laberge has been in fusion for twelve years. He has earned this recognition. The company started as his kooky idea. He has some cash, a PhD and a mid-life crisis. Over time, it has moved down a typical entrepreneurial path (by contrast, EMC2 and LPP have not). Board seats were first given to investors; and then later, to energy industry veterans [35]. This was needed to secure 55 million funding, get mainstream press and to hire the sixty employees [1]. But, the cash comes with strings. If successful - the VC firms will reap the winnings. The company has also been publishing: four papers last year [3-6]. Blogger Henning Dekant recently got a look at their labs [2]. He described it as: “…an engineering approach to fusion and [we] are in a hurry…” Good. We need to hurry.



Michels’ first paper explains the idea simply [34]. It uses a liquid lead-lithium wall. This moves around a spherical cavity. Pumps spin the metal along the equator and draw it off at the poles. This forms a vacuum cavity. Deuterium and tritium is shot into this cavity [36]. This is done with a toroid. It is then compressed by a pressure wave. The cavity reaches fusion condition. If fusion happens, the liquid metal absorbs any products. The liquid metal then exchanges heat with steam. This turns turbines, making electrical power.


On paper, I like this idea. Riders’ thesis tells us that hot, uniform plasma with a bell curve of energy – is a bad direction to go in. This design goes in the opposing direction. It heats the plasma. It spins the plasma. It squeezes the plasma. It combines several old fusion ideas: a liquid wall, a closed magnetic field and compression [40]. Ken Fowler, fusion great, loved this idea [36]. On paper, it looks fine.


We modeled their prototype. This is working, now [46, 45]. The model is rough. Ballpark values were used: this is in design phase so that is fine. Numbers will continue to vary – between tests, targets and what is affordable. The machine has a one meter sphere. Fourteen pistons surround this chamber. They are steam driven. They hit a steel anvil; not the lead itself. This is illustrated below. The outside (a sixteen sided polyhedron) was estimated from pictures.


The chamber is filled with a lead (99.3%) and lithium (0.7%) mixture. This is at 400 Celsius and a density of 10,000 kilogram per cubic meter [38, 39, 6]. It is spun at a few meters per second [47], around a forty centimeter cavity [37]. The cavity maybe evacuated, filled with air or argon [XXX]. Control over spinning really gives them an edge over ICF. It controls their target, simplifying it. This may help with the Rayleigh–Taylor instability.

The Wave:

The compression can be modeled in three parts. First, is the pressure made by a single piston. The piston is fired. It speeds up towards a steel anvil. It hits. The wave is made. The anvil wiggles – moving the wave directly into the liquid lead [40]. An illustration of this impact is shown below [37, 40, 6].


Next, the wave jumps from anvil to the lead. In the process, it loses nine percent of its energy [40]. What happens next, is not fully understood. In the lead, waves move inward. The liquids’ spinning motion may effect this. Waves diffract with other waves - like ripples on water. Mach waves can also form within this diffraction [37]. Additionally, the lead was already pressurized [6]. They focus into the center, and crush the cavity. Before the crush, spinning plasma is injected. The cavity squeezes down to one tenth the size [XXX]. Ideally, this initiates fusion.

Compression Analysis:

The compression is both complex and critical. General Fusion first used a masters’ student to model it [37]. Later, a physicist was hired to do the same job [4, 5, 6]. To simplify the “anvil-wall-lead” system, a cheap finite element software was used [44]. This simplified the wave. The pressure modeled for one piston, is shown below.


This was input for a second software. It was a boundary condition for a CFD code. They used an open-source code for this [42]. Free software; it shows how frugal this team is. The computer looked at two cases. First was a collapsing 2D wave. Next was the same scenario in three dimensions. One result is shown below [6].


Like a wave crashing on a beach. The pressure moves from outside, inward. Waves combine; increasing in power. The energy occupies less space, leading to “geometric focusing”. In half a millisecond, the wave doubles in strength. Ideally, this compresses the plasma in the center, leading to fusion.

Northwest Nuclear Consortium


Carl Greninger is a very passionate guy. His first passion is education; and he is not happy with the trends. He points to a high school dropout rate - in his state - of 24% [7]. Deeper still: Carl is upset that schools are not getting kids excited about science. The kids “…were not impressed, I suddenly saw that while we may be teaching the curriculum - if we’re not inspiring, if we’re not creating passion, then it is a waste of time…” [8]. Fed-up with this, Carl decided to act. He started the northwest nuclear consortium in 2010 [9]. This group is: “the only nuclear engineering curriculum for public high school students in the U.S. with a working fusion reactor” [10]. Each week, a group of students and instructors meet to do nuclear fusion at Mr. Greningers’ home [12].


Standoffish parents - have rapidly become noisy supporters of NWNC. Their kids have collectively won $410,000 in college scholarships [9]. Wow. They are crushing science fairs. They won 2nd place in physics, at the Intel International Science and Engineering Fair beating out millions of other entries [11]. They have also won state, and local competitions [12, 43]. There are four projects/teams listed [13]:

1.Safety Team. A team monitors doses, metals, shielding and personal protection. Unconvinced neighbors called the Office of Radiation Protection [14]. They sent Mike Brennan, a radiation health physicist. Mike declared: “I think that it is not only safe, but he is teaching safety [creating] a culture of safety…”

2.An ion accelerator. This tool speeds ions down a negative 240K voltage. The potential is made using an AC to DC voltage multiplier. The resulting ion beam will add to the groups’ capabilities.

3.Anisotropic fusion. With fusion, come neutrons. Their release is not well understood. A team covered a wall with detectors, charting the neutrons [43]. Results showed most fusion occurring when ions hit the cage, not each other.

Work Cited:

1. "General Fusion." Wikipedia. Wikimedia Foundation, 05 Oct. 2014. Web. 17 May 2014.

2. Dekant, Henning. "Here Be Fusion." Wavewatching. 30 Dec. 2013. Web. 17 May 2014. <>.

3. Carle, Patrick J. F., Stephen Howard, and Jordan Morelli. "High-bandwidth Polarimeter for a High Density, Accelerated Spheromak." Review of Scientific Instruments 84.8 (2013): 083509. Web. 17 May 2014.

4. Suponitsky, V., S. Barsky, and A. Froese. "On The Collapse of a Gas Cavity by an Imploding Molten Lead Shell and Richtmyer-Meshkov Instability." Computers & Fluids 89.20 (2014): 1-19. Science Direct. Web. 17 May 2014. <>.

5. Suponitsky, Victoria, Aaron Froese, and Sandra Barsky. "A Parametric Study Examining the Effects of Re-shock in RMI." Soft Condensed Matter 2013 (2013): 1-43. Arxiv. Web. 17 May 2014. <>.”

6. Suponitsky, Victoria, Sandra Barsky, and Aaron Froese. "Richtmyer–Meshkov Instability of a Liquid–gas Interface Driven by a Cylindrical Imploding Pressure Wave." Cornell University. Arxiv, 22 Oct. 2013. Web. 17 May 2014. <>.

7. Dorn, Randy I., and Robin G. Munson. "Graduation and Dropout Statistics Annual Report." Washington State Office of Superintendent of Public Instruction (2012). Web. 17 May 2014. <>.

8. "Microsoft Manager Teams up with Teens to Build a Fusion Reactor." Interview by Carl Greninger. Youtube. Microsoft Show Us Your Tech, 29 May 2011. Web. 17 May 2014. <>.

9. "Private Conversation." Interview of Carl Grienger. 21 Apr. 2014.

10. Washington State Academy of Sciences, 2013 Symposium Proceedings, October 11, 2013

11. "Intel ISEF 2014." Intel International Science and Engineering Fair, 11 May 2014. Web. 17 May 2014. <>.

12. Greninger, Carl. "NWNC Wins 1st Place at WSSEF - Twice!!" Fusor Forum., 7 Apr. 2014. Web. 17 May 2014. <>.

13. Greninger, Carl. "Home." North West Nuclear Consortium. North West Nuclear Consortium, Jan.-Feb. 2014. Web. 17 May 2014. <>.

14. Greninger, Carl. "Why Are Kids in Federal Way Playing with a Nuclear Reactor?" Interview by Gaberiel Spitzer. Http:// ... ar-reactor. NPR, KPLU. Seattle, Washington, 12 Feb. 2013. Radio.

15. Hurricane, Omar, and D. A. Callahan. "Fuel Gain Exceeding Unity in an Inertially Confined Fusion Implosion." Nature 506 (2014): 343-48. Nature Publishing Group. Web. 20 Feb. 2014. <>.

16. Brumfiel, Geoff. "Scientists Say Their Giant Laser Has Produced Nuclear Fusion." NPR. NPR, 12 Feb. 2014. Web. 17 May 2014. <>.

17. Biello, David. "High-Powered Lasers Deliver Fusion Energy Breakthrough." Http:// Scientific American, 12 Feb. 2014. Web. 15 May 2014. <>.

18. Clark, Jack. "Dr Hurricane Unleashes FUSION POWER at Livermore Nuke Lab." Http:// The UK Register, 12 Feb. 2014. Web. 17 May 2014. <>.

19. Herkewitz, William. "Has Fusion Finally Solved Its Hype Problem?" Popular Mechanics. Popular Mechanics, 12 Feb. 2014. Web. 17 May 2014. <>.

20. Chang, Kenneth, and William J. Broad. "Giant Laser Complex Makes Fusion Advance, Finally." The New York Times. The New York Times, 12 Feb. 2014. Web. 17 May 2014. <>.

21. Press, Associated. "National Ignition Facility Announces Promising Results for Nuclear Fusion." Fox News. FOX News Network, 12 Feb. 2014. Web. 17 May 2014. <>.

22. Boyle, Alan. "Laser Fusion Project Takes One Small Step Toward Energy Leap - NBC News." NBC News. NBC News, 12 Feb. 2014. Web. 17 May 2014. <>.

23. Koch, Wendy. "Quest for Pollution-free Fusion Energy Takes Major Step." USA Today. Gannett, 12 Feb. 2014. Web. 17 May 2014. <>.

24. Kluger, Jeffery. "Nuclear Fusion Breakthrough Sparks Energy Optimism." CBS News. CBS News This Morning, 15 Feb. 2014. Web. 17 May 2014. <>.

25. Kramer, David. "Livermore Ends LIFE." Livermore Ends LIFE. Physics Today, Apr. 2014. Web. 17 May 2014. <>.

26. Nuckolls, John. "Early Steps toward Inertial Fusion Energy (IFE) (1952 to 1962)." Lawerence Livermore National Labs. Lawerence Livermore National Labs, 12 June 1998. Web. 17 May 2014. <>.

27. "National Ignition Facility & Photon Science." Frequently Asked Questions. Lawrence Livermore NationaL Laboratory, Apr.-May 2011. Web. 17 May 2014. <>.

28. "US Fusion Budget for MFE and IFE." Http:// Fusion Power Associate, Dec. 2012. Web. 17 May 2014. <>.

29. Cheng, Baolian, Thomas J. T. Kwan, Yi-Ming Wang, and Steven H. Batha. "Scaling Laws for Ignition at the National Ignition Facility from First Principles." Physical Review E 88.4 (2013). American Physical Society. Web. 17 May 2014. <>.

30. "Fusion Energy Sciences Budget." Fusion Budget. United State Energy, Jan.-Feb. 2014. Web. 17 May 2014. <>.

31. United States of America. Congress. U.S. Global Change Research Program. 2014 National Climate Assessment. Vol. 2014. Washington, DC: U.S. Global Change Research Program, 2014. Http:// Web. 17 May 2014. <>.

32. Gerken, James. "Part Of West Antarctic Ice Sheet Starting Slow, Unstoppable Collapse, Studies Indicate." The Huffington Post., 12 May 2014. Web. 17 May 2014. <>.

33. McKinzie, Matthew, and Christopher E. Paine. "When Peer Review Fails The Roots of the National Ignition Facility (NIF) Debacle." National Resources Defense Council Nuclear Program (2000). Web. 17 May 2014. <>.

34. Laberge, Michel. "An Acoustically Driven Magnetized Target Fusion Reactor." Journal of Fusion Energy 27.1-2 (2008): 65-68. Web.

35. McCollough, Micheal. "General Fusion." Canadian Business. Canadian Business, 21 Feb. 2014. Web. 28 May 2014. <>.

36. Hamilton, Tyler. "A New Approach to Fusion | MIT Technology Review." MIT Technology Review. MIT Press, 31 July 2009. Web. 28 May 2014. <>.
37. Gregson, James. Fluid-Structure Interaction Simulations in Liquid-Lead Simulations of the General Fusion Magnetized Target Fusion Reactor Concept. Thesis. Dalhousie University, 2005. Vancouver: U OF BRITISH COLUMBIA, 2005. Print.

38. Karditsas, Panayiotis, and Marc-Jean Baptiste. "LITHIUM LEAD (17Li-83Pb)." Thermal and Structural Properties of Fusion Related Materials. UKAEA Government Division, Fusion, (Euratom/UKAEA Fusion Association). Web. 18 May 2014. <>.

39. Zinkle, S.J. "Summary of Physical Properties for Lithium, Pb-17Li, and (LiF)n•BeF2 Coolants." Oak Ridge National Labs, APEX Study Meeting, Sandia National Lab 1998 (1998): 1-8. Web. 28 July 1998. <>.

40. Laberge, Michel. "Experimental Results for an Acoustic Driver for MTF." Journal of Fusion Energy 28.2 (2009): 179-82. Web. 28 May 2014. <>.

41. Laberge, Michel. "An Acoustically Driven Magnetized Target Fusion Reactor." Journal of Fusion Energy 27.1-2 (2008): 65-68. Web. 28 May 2014.

42. "The Open Source CFD Toolbox." OpenFOAM®. OpenFOAM group, ESI Inc., 2004. Web. 28 May 2014. <>.

43. Greninger, Carl. "NWNC CR-39 Team Wins the Gold Overall at WSSEF." NWNC Newsletter 1.7 (2013): 1-2. Http:// June 2013. Web. 29 May 2014.

44. "LS-DYNA." LSTC Homepage. Livermore Software Technology Corp., 2011. Web. 29 May 2014. <>.

45. ... al-fusion/
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Re: Review of General Fusion's Machine.

Postby ThePolywellGuy » June 29th, 2014, 1:25 pm

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