Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Compact nuclear fusion reactor is 'very likely to work,' studies suggest

nytimes.com

Post reply on HN
Print view View original

171–180 of 373 posts

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#171

Post by samatman »

pklausler wrote: post #46
mdorazio wrote: post #16

Here's the actual summary: "Although many significant challenges remain, the company said construction would be followed by testing and, if successful, building of a power plant that could use fusion energy to generate electricity, beginning in the next decade." In other words, "very likely" in this case means "if several roadblocks are overcome, it might be a net-positive power generator in a decade". Even so, this…

Speaking pedantically, the next decade actually starts 1-Jan-2021.

This is not even pedantically correct.

I quote ISO/WD 8601-2:

Representation of a decade must be exactly three digits, leading zeros, if any, must be included. Thus the time interval 200 through 209 is represented as ‘020’ and NOT ‘20’; the latter would represent the time interval 2000 through 2099.

Here you can clearly see that the ISO definition of a decade is in keeping with the common understanding, not whatever oddball misunderstanding you've chosen to promulgate.

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#172

Post by pfdietz »

xyzzyz wrote: post #135
dnautics wrote: post #127

Earlier quoted context omitted.

You don't know that. What if you had spent 1000x the budget of the manhattan project on building an atom bomb in the year 1789? You would have gotten squat.

I know that, because we already got ITER, which is widely expected to be energy positive. Moreover, the ITER approach is known to scale upwards: in fact, the ITER is so large, because it's the smallest size that is expected to work.

ITER is expected to be energy positive, but it's a kind of pyrrhic breakeven. The gross power density of ITER will be 1/400th power density of a PWR reactor vessel.

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#173

Post by ClumsyPilot »

Maursault wrote: post #166
RealityVoid wrote: post #98

Earlier quoted context omitted.

I am really not buying the fact that nuclear is expensive because it's nuclear. I think the fears around it, the overregulation and opposition to it make it costly. Obviously, there have been plenty of plants that were profitable. Also, nuclear fusion is possibly the cleanest energy source we could get. If we touch this, we might have a real path forward.

That just isn't the case. Nuclear (fission) has always been the single most expensive way to generate electricity, and the expense has only increased. Uranium is crazy expensive. Security is very expensive. Spent fuel storage effectively never stops costing, and it isn't ever cheap. If nuclear was simply expensive because of regulations, investors would find a way, and you could not beat them away from building nucle…

Thats not accurate at all, Uranium itself is much cheaper than coal / any fuel per unit energy. Some contries have permanent, final storage for nuclear waste, it does not cost any more once created.

Furthermore, not only was solar power borderline non existent when those reactors were built, it is also still intermittent. You are just glossing over the biggest challenge of energy - balancing the powe grid. No-one needs energy if it's only avaliable at the wrong time. Energy storage multiplies cost of renewable electriciry several times over, and no country-scale grid has ever operated on wind and solar.

Lastly, energy is actually cheap - you can see that because we can afford transporting a pair of jeans 4 times across the world in the process of manufacture. We could have had zero-carbon grid since the 70s with nuclear - and France did. Even though France has cheapest energy in EU, suppose energy would be 30% more expensive. So what? We would be so much better off in terms of climate change.

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#174

Post by skykooler »

Florin_Andrei wrote: post #42
isoprophlex wrote: post #8

I never quite understood the math behind power densities in a fusion reactor. In the sun, isn't energy production occurring at something like 100-1000 W/m3? So, if you want to build a multiple MW fusion plant, shouldn't these plants be ridiculously huge compared to, say, a wind turbine rated at a couple of MW? Is the density of the plasma so much higher in a fusion reactor? Also, something else I never grokked, how d…

> In the sun, isn't energy production occurring at something like 100-1000 W/m3? It's just an average. Fusion occurs only in the core, which is pretty tiny, relatively speaking. > The plasma heats up, but how do you turn that into useful electrical energy? The same way you can turn any kind of heat into useful energy.

It's not just that the fusion only occurs in the core, but the fusion rate is also very low; it's only because the sun is so incredibly massive that this slow reaction rate can self-sustain. With a much smaller fusion reactor, the reaction rate needs to be much higher to keep itself going and to create enough power to run the electromagnets that keep it confined.

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#175

Post by Retric »

Maursault wrote: post #166
RealityVoid wrote: post #98

Earlier quoted context omitted.

I am really not buying the fact that nuclear is expensive because it's nuclear. I think the fears around it, the overregulation and opposition to it make it costly. Obviously, there have been plenty of plants that were profitable. Also, nuclear fusion is possibly the cleanest energy source we could get. If we touch this, we might have a real path forward.

That just isn't the case. Nuclear (fission) has always been the single most expensive way to generate electricity, and the expense has only increased. Uranium is crazy expensive. Security is very expensive. Spent fuel storage effectively never stops costing, and it isn't ever cheap. If nuclear was simply expensive because of regulations, investors would find a way, and you could not beat them away from building nucle…

Uranium and even enriched uranium is still reasonably cheap. Fuel rods get expensive, and more critically only using up ~5% of a fuel rod before you need to replace it gets even more expensive. Other reactor designs can use a higher percentage of uranium without reprocessing, but they have other issues. In the end fuel including waste disposal represents about 10% of nuclear reactors operating costs or ~1c/kWh. It’s a significant but hardly gamebreaking cost.

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#176

Post by skykooler »

DennisP wrote: post #162
Animats wrote: post #32

How's the Lockheed effort coming along?[1] [1] https://lockheedmartin.com/en-us/products/compact-fusion.htm...

Looks like they're still working, and on their fifth test reactor, the largest so far: https://www.thedrive.com/the-war-zone/29074/skunk-works-exot...

What happened to General Fusion's steam piston design? It seemed like such an elegant concept.

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#177

Post by credit_guy »

Tossrock wrote: post #150

I wish these people the best, and I really hope they get a working fusion plant soon. That said, I can't resist sharing Admiral Rickover on academic reactors vs practical reactors: Important decisions about the future development of atomic power must frequently be made by people who do not necessarily have an intimate knowledge of the technical aspects of reactors. These people are, nonetheless, interested in what a…

Admiral Rickover was a smart dude. But none of these points are applicable here. This development here is about fusion, not fission, those who are pursuing it are not amateurs at all, they are MIT people and they are not shy to pick up a wrench and use it in a lab. One by one, the points made by Rickover against his adversaries are not relevant here:

1. It is simple: no, nobody says here that fusion is simple.

2. It is small: well, this one is small compared to ITER, but nobody's saying it's small in an absolute sense.

3. It is cheap: sure, compared to the billions and billions poured into ITER, this is dirt, dirt cheap, but still, they have secured $200MM so far, and they will need more money until they build an actual reactor.

4. It is light: really not applicable here, since nobody's thinking of putting these reactors in submarines (which is what Rickover was really talking about).

5. It can be built very quickly: sure, the time horizon is less than the perpetual 30 years of the old fusion reactor proposals, but it's not going to be "very quick",

6. It is very flexible in purpose: no, for the time being, something that just works is fine, nobody cares about flexibility,

7. Very little development is required, it will use mostly off-the-shelf components: nope, there will be plenty of very custom made components developed for just this purpose, and lots and lots of development are required.

8. The reactor is in the study phase. it is not being built now: it is both in the study phase and being built.

In the end, what was Rickover's agenda: some people were competing with him for government funding for nuclear reactor R&D in general, and for naval nuclear reactors in particular. All those people were a nuisance to him, he had to go and plead for funds again and again, so he decided to write this letter to put this thing to rest once and for all. He managed.

But here it's fusion. Commonwealth Fusion is privately funded, they are not looking for government funding, and they are not making inflated representations to the public. They are actually keeping a low profile in general. The message of this article is simply "this time there is a glint of hope", nothing more.

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#178

Post by Retric »

ClumsyPilot wrote: post #173
Maursault wrote: post #166

Earlier quoted context omitted.

That just isn't the case. Nuclear (fission) has always been the single most expensive way to generate electricity, and the expense has only increased. Uranium is crazy expensive. Security is very expensive. Spent fuel storage effectively never stops costing, and it isn't ever cheap. If nuclear was simply expensive because of regulations, investors would find a way, and you could not beat them away from building nucle…

Thats not accurate at all, Uranium itself is much cheaper than coal / any fuel per unit energy. Some contries have permanent, final storage for nuclear waste, it does not cost any more once created. Furthermore, not only was solar power borderline non existent when those reactors were built, it is also still intermittent. You are just glossing over the biggest challenge of energy - balancing the powe grid. No-one nee…

Nuclear has the opposite problem as solar in that it needs high uptime 24/7 to stay reasonably economical. You can easily design a grid following reactor as seen with nuclear subs etc, it just doesn’t save you any money.

24/7 365 grid scale battery backed and thus load following solar runs about 8c/kWh* which is cheaper than nuclear at high utilization. Sure, France’s model of importing and exporting significant chunks of electricity allowed them to ramp up nuclear, but they where exporting power at a loss and utilization still fell into the 80% range.

*Excluding the most northern and southern areas.

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#179

Post by deepnotderp »

xyzzyz wrote: post #124
simonh wrote: post #112

Earlier quoted context omitted.

I think it’s generally very hard to force technological progress along by just throwing money at it. Let’s suppose this proposal works out, ITER will become a very expensive boondoggle. A technological dead end. But if you’d taken the ‘Manhattan Project’ approach and thrown 10x as much money at fusion research 20 years ago we’d most likely have spent most of it on a super-ITER. It might be operational by now and migh…

Sure, but on the other hand, such a lucky break of this new approach might have had never happened. At the same time, if super-ITER approach was shown to work, by producing it en masse, it would likely be cheaper per installed MW than nuclear power, which would remove the need for solar panels and wind altogether. We'd have cheap power with no danger of nuclear pollution, no real nuclear waste problem, and no destroy…

https://www.nature.com/articles/454397c

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#180

Post by [deleted] »

tim333 wrote: post #119
_kst_ wrote: post #67

Earlier quoted context omitted.

Speaking even more pedantically, a new decade is starting right now ... and here comes another one. The 2020s start 2020-01-01 (just as the century called "the 1900s" started 1900-01-01). The 21st century started 2001-01-01. The 203rd decade starts 2021-01-01 -- but nobody talks about the "203rd decade". That's the difference in terminology between decades and centuries; we don't refer to decades by their ordinal num…

Continuing the pedantalization escalation the 21st century started 2001-01-01 if you follow the Gregorian calendar "named after Pope Gregory XIII, who introduced it in October 1582" However if you are not fussed about pope Greg and then and go with ISO 8601 or common usage it started 2000-01-01.

[deleted]
Post reply on HN