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MIT-designed project achieves major advance toward fusion energy

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Re: MIT-designed project achieves major advance toward fusion energy

#341

Post by hoseja »

codethief wrote: post #281
mchusma wrote: post #112

Earlier quoted context omitted.

You are right, people who flippantly dismiss fusion just don't understand it. -Fusion has made consistent improvement, roughly in line with expectations for the level of investment (20 years away predictions were considering if we invested massively, which we did not). - Fusion is in theory something that could give us true energy abundance. Want to just desalinate water like crazy? Want to extract gigatons of carbon…

> Fusion is in theory something that could give us true energy abundance. Well, at least for a few hundred years but then: > if you plot the U.S. energy consumption in all forms from 1650 until now, you see a phenomenally faithful exponential at about 3% per year over that whole span. The situation for the whole world is similar. […] the Earth has only one mechanism for releasing heat to space, and that’s via (infrar…

>(infrared)

How to tell an undereducated journo.

Re: MIT-designed project achieves major advance toward fusion energy

#342

Post by jabl »

AnthonyMouse wrote: post #273
ant6n wrote: post #257

Earlier quoted context omitted.

Again this assumes fusion power will be cheap. But in reality it may cost about as much as (fission) nuclear power. So yes it may help with making energy production carbon-free (together with solar, wind, hydro), but it won't necessarily create a some sort of energy abundance.

The theory isn't that the cost will be low, it's that the output will be high. If it costs the same amount as a fission reactor but produces ten times more power, that's lower cost per MW than anything on the market. Even if it costs more than fission, it could be competitive as long as the more it costs is less than the more it outputs.

But why would a fusion reactor produce 10 times more power than a fission reactor of the same cost? A fission reactor is, comparatively, very simple. Just a steel cylinder filled with fuel and control rods. No superconducting magnets, no zillion degree plasma to contain and control, low neutron field (as long as we're comparing to D-T fusion). Also heat transfer is much more efficient, enabling high power density, since you pump coolant through the entire reactor vessel instead of just the outer edges.

Re: MIT-designed project achieves major advance toward fusion energy

#343

Post by goodpoint »

ifdefdebug wrote: post #289
codethief wrote: post #281

Earlier quoted context omitted.

> Fusion is in theory something that could give us true energy abundance. Well, at least for a few hundred years but then: > if you plot the U.S. energy consumption in all forms from 1650 until now, you see a phenomenally faithful exponential at about 3% per year over that whole span. The situation for the whole world is similar. […] the Earth has only one mechanism for releasing heat to space, and that’s via (infrar…

Well if we transform solar into electric then into motion or bound carbon, that should actually help reduce the heat balance?

Absolutely yes. Energy is captured by solar panels. They make a shade, obviously, and what is in their shade does not get heated by the sun.

If you were to use 100% of solar panel energy to heat up something else the overall balance would be 0.

Contrarily, nuclear fission/fusion that releases energy from its fuel, ultimately heating up the planet.

Re: MIT-designed project achieves major advance toward fusion energy

#344

Post by DanielVZ »

codethief wrote: post #281
mchusma wrote: post #112

Earlier quoted context omitted.

You are right, people who flippantly dismiss fusion just don't understand it. -Fusion has made consistent improvement, roughly in line with expectations for the level of investment (20 years away predictions were considering if we invested massively, which we did not). - Fusion is in theory something that could give us true energy abundance. Want to just desalinate water like crazy? Want to extract gigatons of carbon…

> Fusion is in theory something that could give us true energy abundance. Well, at least for a few hundred years but then: > if you plot the U.S. energy consumption in all forms from 1650 until now, you see a phenomenally faithful exponential at about 3% per year over that whole span. The situation for the whole world is similar. […] the Earth has only one mechanism for releasing heat to space, and that’s via (infrar…

I'd take that statement with a grain of salt. If there's something that COVID has taught me is that in reality exponential curves almost always turn into sigmoids wherever there are limiting factors. The key here is where the curve starts flattening.

The same goes for infinite growth. In the close future it sure looks infinite, but I'd say it's infinitely hard too to predict what will happen in say a 100 years (a fourth of the time before we hit the heat death wall predicted here).

Re: MIT-designed project achieves major advance toward fusion energy

#345

Post by bell-cot »

dfdx wrote: post #34

Plenty of skepticism in these comments. I've been following CFS for a while and can present a point of view for why this time might be different. Fusion energy was actually making rapid progress in the latter half of the twentieth century, going from almost no power output in the fifties and sixties to a power output equal to 67% of input power with the JET reactor in 1997. By the eighties there was plenty of experim…

Not an expert, but... "Net gain" seems to be the "give us enough $Billions and years and we'll find it" holy grail of fusion power. Vs. a $4 Casio calculator I can buy on Amazon today includes a zero-maintenance solar cell that is good for "net gain, plus useful work". Large-scale solar and wind power are already real-world at commercial scale, with costs per MW-h that pretty much beat every alternative. ( https://en.wikipedia.org/wiki/Cost_of_electricity_by_source ) Old-type nuclear (fission) energy has a horrible "what was promised, vs. what was delivered" record.

Maybe your equations and power laws are right, and a "big enough" tokamak would be a competitive source of power. But then there are the details, like "big enough will cost $25 Trillion". Followed by delays, cost overruns, etc.

I'm thinking that a rational, non-expert taxpayer would say, "This fusion thing is a hundred times worse than NASA's Senate Launch System. Stop wasting my money on it NOW, and let gullible investors waste theirs instead."

Re: MIT-designed project achieves major advance toward fusion energy

#346

Post by phscguy »

nickik wrote: post #320
phscguy wrote: post #301

Earlier quoted context omitted.

Sadly no. While I think that it would work and probably be cheaper and easier than fusion, fission has an absolutely abysmal public image. People are terrified of radiation, even if the danger is very low. This means it becomes prohibitively difficult and hence expensive to build and run a fission plant because safety has to be prioritized so heavily. That is even if permission is granted to build in the first place.…

Fusion also produces radiation. So not sure why changing one word to the other should magically change public opinion. We can just rename fission to #goodenergy or something, that would be cheaper then developing fusion. People don't even know that nuclear reactors use fission, so the idea that this would change anything is crazy. People opposed will call fusion reactors 'nuclear' just like they do fission.

The amount of long lived radioactive material produced by fusion reactors is many orders of magnitude less than fission. Iirc it's about the same amount of the radioactivity released as burning coal in a coal plant of the same power output.

Re: MIT-designed project achieves major advance toward fusion energy

#347

Post by pfdietz »

nickik wrote: post #323
pfdietz wrote: post #202

Earlier quoted context omitted.

If reactors were ten times safer but no cheaper, they still wouldn't be being built. If reactors were ten times cheaper but no safer, we'd be building them like hotcakes.

While this is true, its a fact that the regulatory and governmental outlook on fission has prevented these changes from happening. The western world has made development of new fission plants practically impossible. Requiring 100s of millions in development before you might get a hint if the government would actually allow you to build a plant. Thankfully this has finally started to change. Mostly in Canada and that'…

Regulation is the scapegoat for nuclear's failure, but it's equally the case that regulation is vital to nuclear (and to nuclear getting liability caps.) If the risk of nuclear were not socialized no one would build it (or insure it).

What has also prevented changes from happening is that nuclear scales down poorly, so the cost of iterating designs is so large. Making a new kind of PV cell or module, or wind turbine, is comparatively much cheaper, because these are individually much smaller and cheaper. The replicated nature of these sources is an advantage in so many ways.

Re: MIT-designed project achieves major advance toward fusion energy

#348

Post by jonnycomputer »

danans wrote: post #55
rnhmjoj wrote: post #50

Earlier quoted context omitted.

> But are they surmountable AND cheaper than existing nuclear or other energy sources? DT fusion solves the two biggest arguments that are always raised by nuclear energy opponents: storage of nuclear waste (it doesn't produce high-level waste) and safety (it's not perfect but it can't explode). I wouldn't call it a "meh", even if it comes off as much more expensive than fission.

> I wouldn't call it a "meh", even if it comes off as much more expensive than fission. It's not competing with fission, though. It's competing with renewables + storage + load shifting + efficiency. Compared to those, it might indeed be "meh".

I am generally in support of solar and wind. But then, people underestimate the environmental destruction those can entail, depending on the site. Yesterday, I saw a hillside in a very rural part of Appalachia covered in solar panels. Nothing grew on the hill. Because, you know, plants would cover up the panels in no-time, so you have to vigorously keep all of it in check, with herbicides. Aside from the loss of potential carbon storage from allowing trees to grow on the hillside, which very well might offset any carbon-related gains from using solar, it's just bad for the ecology (which is exceedingly rich in the vicinity). Any farm typical for the area would be multiples of times better.

This is not intended as a rant against solar (again, I'm an enthusiastic supporter), but I'd guess a landscape of fusion generators would take fewer square meters of land than the equivalent using solar. And that is nothing to scoff at.

Re: MIT-designed project achieves major advance toward fusion energy

#349

Post by jeremyjh »

amelius wrote: post #336
codethief wrote: post #281

Earlier quoted context omitted.

> Fusion is in theory something that could give us true energy abundance. Well, at least for a few hundred years but then: > if you plot the U.S. energy consumption in all forms from 1650 until now, you see a phenomenally faithful exponential at about 3% per year over that whole span. The situation for the whole world is similar. […] the Earth has only one mechanism for releasing heat to space, and that’s via (infrar…

The thermodynamics argument would hold only for a closed system. If we send big blobs of lava into space, and import big chunks of solid rock back to Earth, then theoretically we should have no problem.

> If we send big blobs of lava into space

I honestly can't tell if you are joking. The energy expenditure to get anything into orbit would produce more heat than you are offsetting.

Re: MIT-designed project achieves major advance toward fusion energy

#350

Post by rnhmjoj »

mordymoop wrote: post #100
rnhmjoj wrote: post #50

Earlier quoted context omitted.

> But are they surmountable AND cheaper than existing nuclear or other energy sources? DT fusion solves the two biggest arguments that are always raised by nuclear energy opponents: storage of nuclear waste (it doesn't produce high-level waste) and safety (it's not perfect but it can't explode). I wouldn't call it a "meh", even if it comes off as much more expensive than fission.

I had heard that one of the major drawbacks of tokamaks was the incredible temperatures lead to situations where the smallest mechanical failure will lead to an explosion of hot, radioactive gas. Is that not the case?

Temperature is not a very good quantity to gain intuition about plasmas (or heat transfer in general): the temperature of the electrons in a incandescent light bulb is around 10000 K, which seems very hot, but since their density is much lower than the air density, the powers involved are quite small and a light bulb is pretty safe to touch.

In the same way, a fusion plasma doesn't hold that much energy because of the extremely low density (4×10^-6 that of air). An explosion (a runaway/chain reaction) is also not possible: the reactor must continuously supplied with fuel or the fusion reactions will stop in a matter of seconds.

There are situations which could result in significant damage to the reactor components, but still not a public safety concern. Distruptions are events in which the plasma confinement is lost and a large amount of heat is released that could damage all components that face the plasma, but reactors are designed to withstand this.

Another drawback, if you like, are runaway electrons, which are populations of relativistic particles that become unbound and penetrare the vacuum vessel for several mm. Again, this is not a particular issue from a safety point of view, but they can do a lot of damage: if they hit a magnetic coil and cause a loss of the superconductivity state, the coil can heat very rapidily (due to the huge current that goes through it) and potentially melt. Replacing such a coil could cost years of maintenance, for this reason reactors are build with many fallback systems.

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