This is probably another ignorant question, but why can't we "aim" and shoot protons at each other to make them smack together without requiring all that heat and pressure?
Why is nuclear fusion so hard?
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Re: Why is nuclear fusion so hard?
#92This is probably another ignorant question, but why can't we "aim" and shoot protons at each other to make them smack together without requiring all that heat and pressure?
Re: Why is nuclear fusion so hard?
#93Here is a thought experiment( no cats harmed or wetted). Show a cat how the toilet flushes, then try to flush the cat. You have two hands, the cat has 4 paws, with sharp claws as well as teeth.
This will give you an idea....
Stars have gravity and mass- we do not, so we must try and compress the plasma, heat it AND stops the paws from grabbing the exterior. In truth magnetic confinement is a poor way to constrain a plasma that wants to leave at high speed = quenches the reaction. There have been many avenues tried and they are making incremental advances, year by year. They say we are 5-10 yearsaway? The ITER Tokamak is well advanced. https://www.iter.org/mach/Tokamak New approaches are being tried that might leap past the Tokamak.
Re: Why is nuclear fusion so hard?
#94Earlier quoted context omitted.
You're both right- technically, nuclear reactors are on of the fastest-ramping sources available. A reactor in SCRAM can drop down to However, zero reactors are capable of doing so economically. The cost of a nuclear plant is in its construction, upkeep, and staff. Those costs are the same at 110% and 30% output, but revenue isnt. In order to turn a profit a nuclear plant needs to be running at 80%+, 24/7. Ultimately…
Nuclear plants have high capital costs and low marginal costs for each bit of energy they make. That doesn't mean they can't produce all the power: France is at 80% from nuclear.
France reduces their penalty from load following by being the largest power exporter in Europe. Most grids drop down to ~30% of peak demand at night, while France only drops to around 75%[1]- almost exactly how much nuclear generation it has, because those nuclear plants are running at 100% as much as possible and exporting power. In 2015 nuclear made up 72% of their generation but only 40% of consumption- 40% of their consumption results in such an oversupply of nuclear that they have to export that much.
If anyone else in Europe tried this, or if the US tried it, it would be prohibitively expensive. Even in France, it's still very expensive- the EDF is 36 billion euro in debt[2]. French nuclear gets 9 cents per kWh in operating funds, slightly lower than the US- but the US is MUCH larger, and distribution costs are included in that. And again, the EDF is heavily in debt.
Nuclear doesn't readily beat natural gas on price, and the areas that it's better than renewables are rapidly shrinking. End of the day we'll need ~40% nuclear in the US, but that's not much growth compared to how much renewables need to grow.
[1]: http://clients.rte-france.com/lang/an/visiteurs/vie/courbes....
[2]: https://www.edf.fr/en/the-edf-group/dedicated-sections/finan...
Re: Why is nuclear fusion so hard?
#95Wrong title. Fusion is easy, plasma physics isn't.
Re: Why is nuclear fusion so hard?
#96Earlier quoted context omitted.
That also shows why fusion power always centers around exotic isotopes like deuterium and tritium rather than plain hydrogen. The reaction paths needed to fuse plain hydrogen are so improbable that they don’t happen fast enough to be useful.
Is this an another way of saying that the only way to fuse to Hydrogen is to create a structure as large and with gravitational features that of a star? Then a star/solar energy is the only way you will ever have large scale fusion energy generation and harvesting.
I suppose the universe doesn't owe us a cheap, easy, unlimited source of energy. A lot of people seem to think that it's inevitable we will achieve amazing, magical feats of technology given sufficient time and effort that are unthinkable today. Maybe. But it's also just as possible that we already know most of the general parameters of what is possible in the universe, and the peak practical feats of technology that will ever be open to us are not all that far off from what we have now. How can we tell?
Re: Why is nuclear fusion so hard?
#97Earlier quoted context omitted.
Base load power is not a useful feature. To follow the demand curve you generally what to turn massive amounts of production off at specific points in the day, base load is simply what you keep running during those periods. Nuclear power plants for example where known to be hard to throttle which was a significant design issue. Historically, the tradeoff is worth it as the cost per kWh was less, but again not a usefu…
I used to be a reactor operator and never saw any evidence they were hard to throttle. That's why they are used for warship propulsion: loads in battle are not predictable by their nature, what with changes in course, catapult launches, etc.
Let’s be more specific.
Compare to hydro which can often do 0-100% or 100%-0 in minutes and has little opportunity cost for doing so. It’s relatively cheap to add max capacity even if you can’t increase average capacity much etc. On the other hand increasing nuclear max capacity is as expensive as increasing maximum sustainable capacity.
Nuclear also has issues going from sub 5% and ramping to 100% with little notice. Thermal stress is an issue ramping up and down frequently over the life of the system. 2x cycles per day is possible but would adds noticeable lifetime costs, 30x per day would cause huge issues. Which means you need to look at ramping as an expense each time you do so which causes incentives to avoid doing so.
PS: Civilian and military reactors are also significantly different designs with different goals. Military reactors are more expensive per GW of capacity, making them a poor though relevant comparison.
Re: Why is nuclear fusion so hard?
#98Earlier quoted context omitted.
It's also a function of not yet having really cheap, scalable storage that's not limited by geography. In any case, it's clear that nuclear can do the job if we're smart about it, because France did it.
Right now, France is running almost carbon-free: 83% nuclear, 14% wind and 10% hydro: http://www.gridwatch.templar.co.uk/france/ But that works in part because they're also exporting 15% of their generation to the UK, Switzerland, Italy and Spain. The export is reducing the need for gas plants in these neighbours, which have higher marginal costs. If France was an isolated grid, or if the neighbours had a similar gen…
Exactly, Hawaii is an example of an independent grid, France does not operate an independent grid any more than Ohio does.
Re: Why is nuclear fusion so hard?
#99QUOTE "I took this fusion class when I was at Georgia Tech and I will never forget it. We started studying and I go, "Man, this is really hard." Charged particles don't want to get near each other. Bare nuclei are both charged, positive charged, they want to avoid each other. And my professor had a really great way of putting it. "It's like going to the mini golf." He says, "You know how in mini golf you've got the v…
What point in the video is this quote?
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Re: Why is nuclear fusion so hard?
#100QUOTE "I took this fusion class when I was at Georgia Tech and I will never forget it. We started studying and I go, "Man, this is really hard." Charged particles don't want to get near each other. Bare nuclei are both charged, positive charged, they want to avoid each other. And my professor had a really great way of putting it. "It's like going to the mini golf." He says, "You know how in mini golf you've got the v…
What point in the video is this quote?