Earlier quoted context omitted.
Fission seems like the better option for mars. The technology is ready now, and no one cares about a bit of nuclear waste on mars anyways.
Space probes require a minuscule amount of radioactive fuel, but launching that into space has still occasionally caused concern among environmentalists, as something might go wrong during launch. Can you imagine the resistance if someone wanted to launch enough processed uranium to support a Mars colony?
U.S. physicists rally around plan to build fusion power plant
231–240 of 240 posts
Re: U.S. physicists rally around plan to build fusion power plant
#232Earlier quoted context omitted.
the physics of Fission work better (or work at all, really) at scale. Fitting the weight and size of a fusion reactor on a rocket ship strikes me as impossible for the forseeable future.
Fusion should lead to unbeatable specific impulses, so the huge size of a reactor may not be a problem at all. (Or maybe it is, I don't think anybody can be sure before there are actually working reactors out there.)
No, because the effective specific impulse is so low, as a fusion reactor will only be able to fuse a small fraction of its mass before it is too radiation damaged to work. ITER, for example, would take 300,000 years to fuse its own mass in fusion fuel, but no DT reactor could operate more than a few years (if that) before parts need replacing.
If you want high effective specific impulse and high thrust at high specific impulse, beamed power is the way to go.
Re: U.S. physicists rally around plan to build fusion power plant
#233How much of the excess renewable energy is being wasted rather than stored? Maybe fuel generation like hydrogen or ethanol, or kinetic can help make nuclear less crucial?
Very little; the term to look for is "curtailment", and it happens a few days a year.
http://www.ercot.com/content/cdr/contours/rtmLmp.html
Right as I post this there's a spot in NE Texas where the wholesale price of electricity is negative 6.275 cents per kWh.
There's a good reason everyone gave up building nuclear power plants in Texas.
Re: U.S. physicists rally around plan to build fusion power plant
#234Earlier quoted context omitted.
The US medical system wastes enough each year ($950B) to start an LHC sized project (~$10B), fully funded, in each US state every year and have enough left over to fully fund three new Apollo scale set of missions ($150B). You can't recover all that, but still, it's hard to picture just how big some of these figures are until you compare to other large costs.
That number is shocking. I'd love to know details. Can you provide a source please?
This was the original article I saw when it was $700B: https://www.theatlantic.com/health/archive/2012/09/how-the-u...
More recent one, I thought it was $950B but this puts it at $760-935B. The potential savings are lower but still in the low hundreds of billions.
https://jamanetwork.com/journals/jama/fullarticle/2752664
I originally started thinking about "how do we understand large numbers" when I saw the article as I think I had roughly the same emotional reaction as I would have done if the number was $70B. Most "big number" comparisons go to things like "dollar bills up to the moon" or "swimming pool full of X" which only gets across "this is a big number". I found comparing it to other enormous projects was hard even as if you take out the US contribution to the LHC you don't move the needle, so you need to then cover all countries costs, then the full project budget for all years and you're still left with almost the entire figure left.
Re: U.S. physicists rally around plan to build fusion power plant
#235Earlier quoted context omitted.
Ethanol is wasteful, hydrogen is a beast to store, kinetic requires too many moving parts. If you want to store renewables you should turn them into methane, best storage volume, safe and proven hardware for storage, transportation and power generation. It’s even better if you can efficiently obtain atmospheric CO2 for the reaction, closes the loop. Honestly, fission is probably the best 0 carbon power technology tho…
> blows everything out of the water I guess that's kind of what I am afraid of. Plus the issue of waste storage.
Re: U.S. physicists rally around plan to build fusion power plant
#236Earlier quoted context omitted.
Fusion is not going to solve the sea level rise problem. You can see this by comparing it to fission. Fission fuels is not expensive on a kWh base, so cheaper fuel is not really a big advantage. Fusion plants produce radioactive waste too (perhaps less?), so you don't save yourself from that headache. Which isn't actually that big of a problem either, even if the costs are probably underestimated for fission plants.…
Wouldn't the major differentiator be the safety standards? You can't have a runaway reaction, because you need energy input to the magnet field to get more energy out. Instead of creating the right environment to get a chain reaction started if your control rods end up in the wrong place. Drop the magnet field and it all collapses. Even if you lose control of it with the magnet field on the quantity is limited, tokam…
While the fusion reaction itself isn't very dangerous, the magnetic coils in a fusion reactor can potentially quench, causing them to explode, which because of their position will throw radioactive debris from the irradiated reactor vessel all over the place, as well as your tritium breeding blanket which will be highly flammable, toxic, and a bit radioactive. Worse, you can't make the magnets passively-safe.
Then there are the standard issues like tritium release. And you have nuclear proliferation concerns as a fusion reactor is great at making plutonium by just doping the tritium breeding blanket with some natural uranium. In fact, the first "fusion" reactors will probably do this anyways as they need to produce more tritium to get more reactors online and because this dramatically increases power output - so you get all the fun of dealing with fission products too.
I would be willing to bet complying with the safety standards for fusion will in fact be more expensive than for fission. Yes the general population doesn't have the same irrational fear of fusion that it has of fission, but once people start seriously proposing to put these in people's backyards that will likely change.
Re: U.S. physicists rally around plan to build fusion power plant
#237Earlier quoted context omitted.
If it's a pebble bed design, easily. Pebbles are uranium coated with multiple protective layers, extremely strong. They could be collected and reused if the launch vehicle plainly explodes on the launch pad.
I think the problem is more when it explodes when the rocket is already going mach 10 and the resulting explosion scatters thousands of radioactive pebbles across several thousand square kilometres of Atlantic ocean, possibly hundreds of metres deep.
Re: U.S. physicists rally around plan to build fusion power plant
#238Earlier quoted context omitted.
Its amazing how cutting emission by regulation is completely left out of the list of options, somehow spending infinite money is seen as easier than getting congress to act... Anyway, I let Wellerstein reply to this: """The Manhattan Project was an unusual, somewhat dubious enterprise that had massive, world-affecting consequences. Ignoring that not only misunderstands the Manhattan Project, it misunderstands what ha…
Cutting emissions by regulation is a continually losing battle. You can't tell people to live a lower-quality life and expect to win elections, and you'll have the combined lobbyists of a lot of different interests against you. It's actually more tractable to invent fusion than to try and win that battle long-term -- at least it's theoretically possible to make fusion work. And heck, if we could put some $ in pockets…
Fixing market failures increases economic wellbeing.
Re: U.S. physicists rally around plan to build fusion power plant
#239Ok, say I've got a new design for a fusion reactor, but it takes me 5 years to convince anyone that it's worth investigating. Fusion power has been set back 5 years. Someone please help me evaluate my design. Please! http://www.DDPROfusion.com
Re: U.S. physicists rally around plan to build fusion power plant
#240Earlier quoted context omitted.
I've been helping with messaging for somebody looking for demonstration funding for an experimentally proven clean oil recovery technology and it makes me feel hopeless seeing there are so many people struggling to demonstrate potentially game changing technologies, often because people investing or allocating money have little technical competence. for those curious: http://www.envirotechdme.com If I could offer you…
Thank you for your advice. Communicating a new idea effectively is quite difficult. I have been thinking about doing some explainer videos. I took a look at your site and had some thoughts I wanted to share with you.