1) Estimated $40 billion USD need to build a test reactor.
2) Not enough FLiBe fluid (Low-Z fluid) on the planet for the reaction chamber. Would need large scale manufacturing.
Source: https://youtu.be/KkpqA8yG9T4
The MIT ARC design is half the size using high temperature superconductors and should be in the $1-2 billion range for a full-scale 500MW pilot production fusion reactor.
What is currently being proposed (the subject of the papers being delivered tomorrow) and funded with private money is a $200-250 million SPARC (Smallest Possible ARC) that is half the size again of the full-size ARC.
So yeah, you are off by a factor of 160.
Maybe if I said it would cost more to build, people would think it more likely to work.
I had many discussions with the head of the physics department at the local university who is a specialist in plasma physics. He was of the opinion that it would work at very low pressures/densities, but that the total output would not be high enough to be commercially viable. What is the actual benefit of a room sized $100k fusion reactor that can only put out 100 watts of energy?
I believe I've solved many of those problems, but building a prototype costs $$ that I don't have to spare...
I could bankrupt myself to build the prototype but I can't gamble like that with assets that currently feed my family.
Though I strongly believe it will work, I'm not going to go down the same hole that Tesla went down. I have no intention of dying penniless surrounded by pigeons. I am on track to build the prototype myself without going into debt in several years once a few of my mortgages are paid off.
Right now I own 100% of the IP, and have a submitted patent. I'm not actively looking for funding that would dilute me unless it's a very good deal. I'm kind of stuck bootstrapping unless I can get a grant. I have applied for several in the past, but to no effect.
Being more expensive doesn't make people think it is more likely to work. The easiest way to make people think your design will work is to take an existing design with known parameters and make it 'better'. Unfortunately, 'better' often means bigger and more expensive, which is how we get to projects like ITER. SPARC is a version of a compact tokamak using advances in high temperature superconductors - thus, 'better'.
A different way is to propose something completely different than what has been done before. Then, if it is cheap enough, people may be willing to take a chance on it. This is what I did. However, it needs to be different enough to not be easily dismissable as having the same problems as an earlier design. For example, if you are doing a mirror design, you better have a good answer for fixing the ends.
One thing that often gets overlooked when talking about cheaper fusion designs is speed. Big projects like ITER take a long time to build, and then a lot of experiments get done on them, taking more years, because you need to get your money's worth from them. Smaller designs get the knowledge gains out of the design much faster. Robert Hirsch has been trying to bring this to our collective attention ever since he converted from a tokamak proponent to opponent decades ago.
My answers to the questions in the video are:
Fuel: D-D
Temperature target: 15kev
Confinement: hopefully approaching ideal at small ion counts. (penning traps are very good at trapping particles for long periods of time)
Instabilities: unknown but probable at high ion counts. I know there will be challenges to solve, but hopefully they are not fatal problems.
I believe the first prototype could achieve Q>1
A single ARC reactor would use 40% of this.
The total world Be resource is estimated at 100,000 tonnes, and if fully used in ARC reactors would supply just 1% of the world's primary energy demand.
Uranium was produced at a level of only hundreds of tonnes per year before the development of nuclear weapons and reactors. Now it is produced in quantities of tens of thousands of tonnes per year. Obviously the terrestrial geology of uranium did not change quickly; industrial demand is what changed. Uranium's crustal abundance is comparable to that of beryllium.
Despite cumulative production of more than 2.2 million tonnes uranium through 2003, additions to resource totals have kept pace with production so that overall resource levels have remained level or have increased over time. The ratio between Known Conventional Resources and reactor-related uranium requirements in 2003 was 52 compared to an average of 47 since 1985.
...
Uranium production in 1945 is estimated to have totaled 507 tonnes uranium. By 1965, when the first Red Book was published, production totaled 31,564 tonnes. Production peaked in 1980 at 69,692 tonnes from 22 countries. In 2003, uranium production was reported by 19 countries with output totaling 35,492 tonnes. Cumulative worldwide uranium production between 1945 and 2003 totaled 2,204,732 tonnes...
"Forty Years of Uranium Resources, Production and Demand in Perspective: The Red Book Retrospective"
https://www.oecd-nea.org/ndd/pubs/2006/6096-40-years-uranium...
It's a fair point that beryllium exploration and extraction would have to increase tremendously for routine construction of these reactors. But putting 100,000 tonnes of beryllium in ARC reactors would not mean that the Earth has then run out of beryllium.
If you look at the history of the price for aluminium, it has steadily dropped as production has risen, which is the opposite of what you are saying. And to pick another metal, the lowest copper price of the last 100 years was around the year 2000.
I'm not trying to make predictions about the price movement of beryllium following a very successful ARC demonstration. I'm just pointing out that you can't look at current resource levels and divide by annual production rates to learn when resources will fall to 0. Making predictions about future prices is particularly hard when an element currently has only niche uses (e.g. beryllium, thorium, thallium, rubidium).
That said, if Fusion power ever becomes a reality I hope it doesn't depend on some difficult to source material.
Sodium and potassium are pretty abundant.
That of course leaves the problem of needing relatively large amounts of 6Li, but that's something one has to live with as long as one wants DT fusion, I guess. And it seems this is more with building up the enrichment capacity rather than some fundamental geological limits.
It might be possible to use lead for neutron multiplication (it has a nice high cross section for (n,2n) reactions above 8 MeV), but it would not moderate the neutrons much, and 6Li breeds best off thermal neutrons. So the blanket and reactor would have to be bigger.
The zirconium does not have to be "nuclear grade", since the design not only tolerates hafnium (a strong thermal neutron absorber) in the coolant salt, it depends on it to shield the reactor structure from thermal neutron degradation.
Lithium-7 will still lead to production of some tritium. Any MSR using lithium is going to need a tritium separation and capture system.
https://arxiv.org/pdf/1409.3540.pdf
I presume that the breeding ratio would fall below 1.0 with natural lithium.
DT fusion has the nasty circular dependency that breeding blankets are needed to make tritium, but they cannot be tested without working high intensity DT fusion neutron sources.
The demonstration reactor is the SPARC which is based on a scaled down half-sized (but 1/8 the mass and 1/8 the cost) version of ARC. While the main goal of SPARC is to achieve significant net power output, along with a proof-of-concept for many of the design features of ARC, some features may have to be left out for lack of space.
So I don't know if SPARC will be able to achieve net tritium breeding, but I presume they will be testing as many of the features as they can along with taking measurements and verifying the model. It is also noteworthy that the ARC/SPARC design allows for replacement of the vacuum vessel and cooling blanket without complete removal of the outside magnetic coils, so they foresee design iteration of those components unlike the ITER design which will be pretty much locked in.