Do We Know Enough (Now) To Say If Fusuion Power Reactors Are Impossible?

Despite 60 years of R&D, we seem to have made little progress in fusion power.
We have ahcieved fusion-but only for short intervals, and with an enormous input of power (thousands of times what is released by the reaction).
So I pose this question: are we at the point at which we ought to forget about fusion power?
It seems to me, that the engineering problems are almost insurmountable-the materials we would use for such a reactor would fail within hours.
Moreover, the intenses neutron radiation would make the design and operation of such a reactor problematic.
I don’t think we ought to abandon all fusion research-but is it time to invest more in feasible fission reactors (pebble bed reactors, thorium fueled reactors, failsafe designs, etc.).
If there are some fundamental problems with fusion (that we cannot overcome), maybe we should rethink our efforts?

We know enough to know that they are possible. We don’t know if they are possible cost-effectively.

It took about 2,300 years from the time Archytas built a steam-powered mechnical bird until the Wright Brothers were able to figure out how to control power, lift and steering (and the totally unrelated invention of the internal combustion engine) to make powered mechanical flight possible.

It was about 50 years between the first theoretical work on atomic particles and the first controlled nuclear fission, and a similar amount of time between the theoretical idea of laser beams and the first working model, so 60 years isn’t all that long in the scientific scheme of things.

We have been past the energy break-even point for decades. We know more than one way to construct a fusion reactor in which pumping in X megawatts will result in an output of 2X megawatts.

The problem lies in building such a reactor in which consistently and safely over years or decades fusion may be used as a power source at an affordable cost in initial infrastructure and operating costs. And where the theoretic possibility has been demonstrated to be real, it’s just a matter of applying enough engineering knowhow to get the job done.

As a WAG, I’d hazard the guesstimate that ExxonMobil, BPAmoco, et al. spend several times in lobbying, advertising, and campaign contributions in a single year what is expended on fusion research over a couple of decades. If appropriate laws made it economically beneficial to them to pursue how to build economically feasibe fusion power plants, my hunch is we’d have them wityhin a couple of years.

Given insane funding levels, I’d still expect it to take a decade or so for the first power plant, and then perhaps another decade for widespread installation. It takes time just to build one of these things, and you’d need to go through multiple iterations before you got the design just right.

With current non-insane funding levels, we’re probably looking at more like 50 years.

Well, it’s obviously possible, there’s one in the sky right now.

Ok, let’s use that one! Oh wait… :slight_smile:

I’ll call BS on all of this.

We know how to make oil refineries. Sure, there have been advances in technology, but we’ve got the basic idea down.

Even so, with unlimited funding, minimal regulatory worries, and freely available land from some community/state, it would still take several years to bring a new refinery online. With more limited funding and more care in environmental/community concerns, it takes the better part of a decade, if not longer. Even in other countries, refineries take the better part of a decade to bring online, if not longer. Delays in construction can create supply shortages, as we saw in Iran a couple years ago.

For new technology like fusion, it is completely unreasonable to expect them to build a fusion reactor faster than they can build a refinery.

Also, while they may spend quite a bit on lobbying and advertising, they are ultimately beholden to shareholders. I will guarantee none of the oil majors spend anywhere close to a $1 billion a year on these activities. Basic research is not necessarily expensive, but the construction costs for ITER (at least $20 billion as of now and rising) well exceed what the oil majors spend combined on lobbying and advertising efforts for a single year or for several years.

I’m not saying the oil companies are good guys or anything, but the idea they can create miracles is astounding. It’s a lot like how people in developing nations think of the US. Just because the US is the richest, most powerful country in the world doesn’t mean we can just make all their problems go away - no matter what they think of our capabilities.

To answer the OP - No, as far as we know (and we now know a lot) there are no fundamental problems with achieving fusion power, and No, now is not the time to abandon R&D into fusion (both magnetic and inertial). It’s not certain we can produce electricity from fusion economically (the idea that chucking infinite cash at it would produce a power station in a couple of years is just wrong) but if it does work it is a power source for the second half of the century and beyond. My kids will be in their 60s in 2050 and I want them, and their kids, to have the chances we’ve had. Given the pay off if it works the money the world is spending on it now is well worth it.

Just for comparison, the UK alone is spending over $14 billion on the 2012 Olympics against the $22 billion the whole world is spending on ITER.

FWIW, I think that a fundamentally new idea will be needed to make it feasible. During most of the 2300 or whatever years it took to develop powered flight, people thought you flew by flapping wings. Balloons were a kind of flight, just relatively slow and hard to control. Gliders were an important way station to powered flight. Even so at the same time as the Wright brothers there were a number of other unsuccessful attempts at powered flight. But I say that gliders were the new big idea. The hard thing the Wrights did wasn’t the power but the control. Even so, there were a lot of crashes and deaths in the early days of flight.

Take computers. There were purely mechanical computers, some of them reasonably successful. Even Babbage’s design could, in principal, have worked. Vannever Bush’s differential analyzer certainly worked. Electronic computers cam along and worked, sort of. The trouble was tubes kept burning out. The MTBF of the Univac I was five minutes and the machine kept saving its state on tape to allow restart. Transistors change all that, especially integrated circuits.

I don’t think current fusion designs are going anywhere, but I would be very hesitant to say that it is impossible in principle.

Speaking of which, I’d be stunned if in 50 years time we haven’t figured out a way to use all that wasted sunlight to power almost everything. Despite the cool factor of fusion reactors, it’s only a matter of time before we tap into the sun itself in a big way, which might make fusion energy almost entirely moot over the next century.

It’s always been “50 years” away for a good half-century now. Scientific American did a nice article on the current state of the problem in March 2010. The overall tone was “don’t bet the farm we’ll ever figure it out in any realistic timeframe”, e.g., don’t wait for fusion power to save Earth (oops, I mean the biosphere we’re adapted to) from fossil fuel burning.

Oh, it certainly won’t be soon enough to save us from global warming-- We’ll need other technologies for that. That doesn’t mean it’s not worth pursuing, though.

I just wonder about the reactor itself…our presnt day fission reactors suffer from neutron damage-the steel pipes become brittle, and after 40 years or so, the reactor must be shut down. A fusion reactor would have thousands of times the neutron flux-do we have materials that can withstand this?

Forgive me for being ignorant, but I thought fusion used preexisting deuterium from heavy water and the usual everyday protium, without any extra neutrons. Where does the flux come from?

IIRC for some time a primary engineering issue has been that the reaction itself tends to massively irradiate and (over time) compromise the structural integrity of the containing mechanism. Until this is solved fusion is not going anywhere.

Fusion Power wiki

The easiest fusion reaction to achieve is actually the fusion of deuterium and tritium. This results in an atom of helium-4, and a high energy neutron. This reaction is undesirable due to much of the energy being released in the damaging neutron, but it is also far easier to achieve than any other reaction.

Then there’s the deuterium-deuterium reaction. This is harder to achieve than deuterium-tritium, but cleaner. Half the time this reaction results in an atom of tritium and a proton, and half the time it results in an atom of helium-3 and a neutron.

Fusing deuterium with normal protons is not a viable reaction.

Yeah but try getting that design past the EPA nanny-staters today.

It’s simple. You just pitch them on all the magnificent tans we’ll have.

Must have been running Windows.

One of my professors worked on the research torus in Oak Ridge. I remember him saying at the time what the plan was for reactor vessel but can’t for the life of me think what that was these many decades hence. If I had to guess I would say they were going to change it out after some period of time. Given it would be within huge coils of wires I am not sure about the practicality of such an operation.

With the laser type approach to fusion you have the added difficulty of how to get the power out. With a torus it is relatively simple. Not so much with the other process.