Reply To: would nuclear energy really be accessible to all?

[TimS]

From the CNN article,

General Fusion aims to achieve net gain fusion experimentally in 2012. By 2018, it plans to complete a power plant prototype that would generate 100 megawatts, enough to power about 100,000 homes.
“We would like to be in a commercial stage of being able to take orders and build power plants by the end of the decade,” said Michael Delage, General Fusion VP of business development.

If I understand correctly from this and several other sources, the General Fusion guys are building a demonstration reactor right now, not just a research device. As far as I know this is a new thing and breaks the current fusion paradigm. Instead of being some giant (ITER, NIF, etc) project, or some cool little plasma research project (LPPX, PWELL, etc), they are using an already developed plasma manipulation technology (MTF) that has not provided critical plasma parameters for fusion tied to a chamber with 200 air hammers… Basically about as brute force as you can get, ugly, expensive, radioactive, but they are building a fusion reactor out of it right now. If it works it will shatter the Tokamak paradigm that you need 10-100 billion dollars and 20-40 years to build a demonstration fusion reactor, and finally more sensible fusion technologies, such as DPF, might get some real funding.

General Fusion Reactor Diagram
They are building a 3m diameter sphere with places for 200 big air hammers on the outside, and MTF spheromak (semi-stable plasma rings, like plasmoids but much larger) generators at the top and bottom. The MTF technology has already been well developed elsewhere, there is a guy at Los Alamos interviewed in this article who has been working it for decades, but it has not achieved critical density / temperature for fusion. By banging a few dozen hammers and focusing the shockwave inside the sphere with a fluid, spheromaks at the middle should go critical. Banging some hammers on a fluid filled sphere is not exactly new science- this is just a massively complicated engineering problem (mostly involving synchronizing the hammers). As the article says, shortly (within a year or so) they plan to have built enough hammers and a good enough synchronization system for a critical reactor that achieves break even.

Then there are a couple of years for practical issues- their demonstrations so far have used water as the fluid and a tube through the water for the plasma which gets crushed by each shot. The plan is to use molten lead for the fluid to protect from the fusion neutrons, with molten lithium in the lead to breed tritium as a source for DT fusion, and spin up the molten lead lithium mixture to make an opening in the middle for the plasma like the opening in water as it spins around a sink before going down the drain. They also will need to build the rest of the 200 hammers the system needs for full operation, all synchronized to generate a shockwave in the middle on time-scales of 1-100 microseconds. These are engineering issues, no plasma research and nothing ‘scientific breakthrough’-ish about it.

Once they get all this to work, they shoot it once a second, take heat out of the molten lead using a heat-exchanger / steam turbine combo, and they have a fusion reactor power generator. This is a big-ugly-absolutely no finesse way of getting MTF to work, not very attractive to your average fusion scientist, but the thing is it is just an expensive engineering problem. The Los Alamos MTF researcher says if they can solve their engineering issues to provide the needed shockwave, then it should generate the output energy they claim. The guy named Laberge who dreamed all this up was engineering parts for Kodak printers, but he actually got his doctorate in plasma physics when he was younger and was interested in fusion at the time, and he decided to go back to his roots and do something for the world. His company is getting the money it needs. A fund with Jeff Bezos, the founder of Amazon, just put in $20 million, and they already had millions.

I think it is quite possible General Fusion will be selling reactors before there is a prototype DPF. And their reactors will be big, ugly, noisy, expensive, deal with bunches of radioactive material from the tritium and high energy neutrons, and not very reliable. Kind of like first generation analog cell phones, but radioactive. Did I mention expensive? Consider heat exchangers and steam turbines, interfacing with molten lead laced with radioactive tritium. However, for comparison current power reactors cost billions of dollars.

tl;dr

My point is their success could be a very good thing for the fusion field, and for LPPX in particular. How many billions of dollars every year are invested in cell phone technology these days? Would all that money be invested if passing the initial hurdle of demonstrating some type of cell phone had not occurred? Why does DPF need to be the first commercial fusion reactor? Once we get past investors thinking about fusion as something that will never actually happen, to investors thinking about the merits of various types of reactors, I expect DPF to take off. Especially considering the radioactive part.