Next Big Future : brian wang on 8/19/2015
In April, General Fusion issued a crowdsourcing challenge to come up with a written proposal for a “robust seal technology” capable of withstanding extreme temperatures and repetitive hammering for the purpose of isolating “the molten lead from the vacuum” inside their fusion reactor.
And after examining the 60 credible proposals submitted from 17 different countries, the General Fusion team has selected the winning entry proposed by Kirby Meacham, a Cleveland mechanical engineer who trained at MIT.
The challenge for the “Method for Sealing Anvil Under Repetitive Impacts Against Molten Metal” was issued via the Massachussets based Innocentive crowdsource platform, with over 335,000 registered “solvers” in almost 200 countries, all poring over similarly complicated technical problems submitted by innovators seeking the wisdom of the crowd to overcome a particular technical hurdle.
The winner of General Fusion’s anvil seal challenge claims his $20,000 prize in exchange for transferring exclusive Intellectual Property rights to the solution.
General Fusion is already hinting at using the Innocentive platform again to gain insight into its experimental plasma physics data.
General Fusion is set to close another round of funding in late summer 2015, with the participation of additional investors.
General Fusion is nearing significant milestones. General Fusion’s Approach is Magnetized target fusion (MTF). Magnetized target fusion is a hybrid between magnetic fusion and inertial confinement fusion. In MTF, a compact toroid, or donut-shaped magnetized plasma, is compressed mechanically by an imploding conductive shell, heating the plasma to fusion conditions.
General Fusion has a full-scale prototype [of the injectors and other subsystems], twin plasma injectors resembling five-metre-long cones, each attached to opposite ends of a three-metre-diameter sphere, would pulse a few milligrams of hydrogen gas, heat it until it becomes a plasma, and inject it into a vortex of swirling liquid metal. Electricity circulating in the plasma would create magnetic fields that bind the plasma together and confine the heat.
From there, an array of as many as 300 huge pistons attached to the sphere’s shell would act like synchronized jackhammers, ramming it at 200 km/hr. This would send shockwaves into the very centre of the chamber, compressing the hydrogen isotopes to 100 million degrees celsius — hot enough for fusion to occur, and good enough to generate clean electricity from steam turbines.
General Fusion reached its milestones on the piston timing about two years ago. Technicians are now perfecting functionality of the plasma injectors.
The nearly 200 capacitors that send 10-gigawatt bursts into General Fusion’s machine were “recycled” from an old laser fusion experiment in Los Alamos, New Mexico.
Here is 2013 paper on the progress on the driver timing and the injector work.
General Fusion, which shares investors with D-Wave, is about two to three years out from creating its own power plant. Today, the pistons work well, and the plasma is hot enough and dense enough. Within the last month, the gas donut has started lasting long enough for the system to work, so now the company is turning its focus to compression and timing, according to Michael Delage, VP of strategy and corporate development.
General Fusion thinks it can provide power at a cost of seven cents per kilowatt hour, comparable to the cost of coal.
General fusion also wants to heat the spheromak to 500 eV before injection. They have reached 200 eV, while they would want to reach 500 eV and expect actually to exceed 600 eV.
In the TEDX talk of 2014 – there is the offhand mention that the plasma lifttime issue of getting to 100 microseconds had good progress
The Plan from 2012
In a 2014 Nature paper, there is the statement that the General Fusion “beefier” prototype will be built perhaps by the end of 2016.
General Fusion has demonstrated the idea with a small-scale device, using pistons driven by explosives, and has raised about $50 million from venture capitalists and the Canadian government. If the company can win another $25 million or so, Laberge says, it will build a beefier implosion system that can compress the plasma to the levels needed for fusion — perhaps within the next two years.
Not sure if the beefier prototype would be the net gain prototype since previously that was $80-100 million.
General Fusion is developing full scale subsystems to demonstrate that they can meet their performance targets. This includes full scale plasma injectors and acoustic drivers, and liquid metal vortex compression tests. Every step is matched with simulation to guide ongoing development work.