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Nuclear fission fuel is inexhaustible (2022)

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Re: Nuclear fission fuel is inexhaustible (2022)

#71

Post by [deleted] »

baybal2 wrote: post #47
HPsquared wrote: post #27

Earlier quoted context omitted.

That chart overemphasizes waste heat. 1 MJ of heat at 50°C is a lot less valuable than 1 MJ of electricity. They are not interchangable. The 1 MJ of electricity could pump much more than 1 MJ of low-grade heat, and it would take a lot of low-grade heat to generate 1 MJ of electrical energy. The parameter of interest is exergy. That is, usable energy. https://en.m.wikipedia.org/wiki/Exergy

And important note that relatively modern coal and gas powerplants are more thermally efficient than nuclear. Nuclear is ran in between 250C-350C, which is rather inefficient, and requires very big turbines.

[deleted]

Re: Nuclear fission fuel is inexhaustible (2022)

#72

Post by SigmundA »

baybal2 wrote: post #47
HPsquared wrote: post #27

Earlier quoted context omitted.

That chart overemphasizes waste heat. 1 MJ of heat at 50°C is a lot less valuable than 1 MJ of electricity. They are not interchangable. The 1 MJ of electricity could pump much more than 1 MJ of low-grade heat, and it would take a lot of low-grade heat to generate 1 MJ of electrical energy. The parameter of interest is exergy. That is, usable energy. https://en.m.wikipedia.org/wiki/Exergy

And important note that relatively modern coal and gas powerplants are more thermally efficient than nuclear. Nuclear is ran in between 250C-350C, which is rather inefficient, and requires very big turbines.

Nuclear does not emit carbon when used, the waste heat means very little, emissions are what matters when discussing efficiency.

Plutonium 239 is also 83,610,000 MJ/kg vs coal at 35 MJ/kg so the difference in thermal efficiency is nearly meaningless given how much specific energy density advantage nuclear has.

Re: Nuclear fission fuel is inexhaustible (2022)

#73

Post by throwbadubadu »

roenxi wrote: post #15
gmerc wrote: post #14

Earlier quoted context omitted.

Surely a nuclear accident will affect 600x more people than a plane crash…

It'll kill a lot less people than a plane crash.

Kill is anyway a very bad metric for something that (if at all) will only manifest in some dice rolls of many dice probabilities involved in the cancer and other illnesses rolling game. In that sense, always surprised that deaths by coal exhaust get fully overattributed, but that this is completely ignored (e.g. when also claiming that Tschernobyl caused only few deaths, while we see a lot of young people still suffering today). Hard to take it serious then :/

Re: Nuclear fission fuel is inexhaustible (2022)

#74

Post by zokier »

zerodensity wrote: post #35
zokier wrote: post #7

If humans were perfect then all problems are trivial. In cryptography there is the idea of misuse resistance, and the same line of thinking applies to other fields where things are expected to be used at scale. Wind and solar are pretty much idiot-proof, and their low density means that the risks are spread out also. As someone who is in principle pro-nuclear but has been following the process of OL3, I am pretty pes…

> Maybe nuclear will make a comeback once the now installed wind/solar plants reach end of life and need replacement, but before that it is just too slow and uncertain to be effective tool (with our current engineering/construction capability!) to combat climate change imho. If we do not start working on brining nuclear power online now it will not be ready when the current generation of renewables needs replacement.…

> Does it matter if nuclear takes 15-20 years to build? No, it does not matter. When it's built it will help out.

It matters because every dollar put into nuclear is dollar away from something else. Sure it would be great to have more resources put into nuclear power, and even more so into fusion power. But right now we are at a situation where that can not happen at the cost of things that have more immediate impact. That is simply the nature of having existential crisis at our hands right now, not in some far future.

Re: Nuclear fission fuel is inexhaustible (2022)

#76

Post by jillesvangurp »

_n_b_ wrote: post #38
jillesvangurp wrote: post #12

The article has a great flow chart in it that highlights rejected energy and energy services and where the rejected energy comes from. energy here spans the spectrum of electricity generation, heating, industrial usage, transport, etc. Basically more than two thirds of the energy is lost to heat, friction, noise, transmission losses, etc. Most of the losses are coal, gas, and oil. Important to note that the image is…

> Nuclear has a useful role to play. But it is in decline. In the US, absolute nuclear generation has been relatively stagnant over the last 10 years as plant shutdowns have been compensated by uprating other plants[1]. About 2.2 GW are coming online via the Vogtle 3 & 4 units, more updates are coming, and the Palisades unit may restart… so I think you’ll see that number creep up a bit. Existing nuclear is economical…

Well according to the two graphgs for 2018 and 2019, nuclear declined a bit in the US. Not surprising because there were some plant closures and not a whole lot of plant openings. And nothing is on track to be added any time soon. Maybe one or two plants.

New nuclear is a bit like an oil tanker (pun intended, sorry): just very slow to ramp up new capacity. This boom you are talking about is so far not adding up to a lot of capacity being delivered. We're talking a few gw here and there. Solar and wind are being deployed by the tens of gw per year. Same with battery.

I believe we'll see some nuclear plants being approved for the next decade. And maybe these modular reactors start delivering on their promises. I still think they are expensive. But why not? Unless something happens on the cost front, that will remain a minority of useful output.

Re: Nuclear fission fuel is inexhaustible (2022)

#77

Post by zerodensity »

effed3 wrote: post #60
rayiner wrote: post #37

Nuclear is the only optimistic energy solution—I.e. one that could enable continually increasing human prosperity, rather than rationing. Forget simply replacing today’s energy generation. That’s sad. What does the future look like when we have 10 times as energy available? Moreover, technology that will “level up” civilization is almost certainly going to be an outgrowth of nuclear development, or something similarl…

>What does the future look like when we have 10 times as energy available? What does the future look like when we have 10 times the efficency on energy use? This is the right question/goal. Denemark (IIRC) has sometimes reached the 100% solar/wind coverage, sure in a sunny day and low demand situation, but 10 years ago this was unthinkable. This appear the true way of prosperity, not the growt of availability/consump…

Having excess energy is great!

We can use it for alot of useful stuff. For example to:

- Recycle waste products. Most (not all) things are recyclable you just need the energy.

- Grow food vertically so more land can be nature.

- Siphon greenhouse gasses out of the atmosphere.

- Desalinate Water

Re: Nuclear fission fuel is inexhaustible (2022)

#78

Post by petree »

peteradio wrote: post #64
bigfryo wrote: post #63

Earlier quoted context omitted.

I think we will outlive the Sun. I think it's possible that we will repair the Sun and prevent its death..

How would you repair a sun? It would seem to defy some entropy laws but what do I know?

A star is just a giant fusion reactor. We just need to add more fusion material (hydrogen) and remove the waste material, which gathers in the core and makes it more difficult for the fusion reaction to continue. It would be possible to prolong the life of the Sun for a while by adding more hydrogen to it, and ideally taking out the heavier elements at the center, which might also be valuable on their own. This seems pretty impossible today, but given we survive enough time until this becomes a problem, then we might find ways to also fix it.

Re: Nuclear fission fuel is inexhaustible (2022)

#79

Post by abecedarius »

peteradio wrote: post #64
bigfryo wrote: post #63

Earlier quoted context omitted.

I think we will outlive the Sun. I think it's possible that we will repair the Sun and prevent its death..

How would you repair a sun? It would seem to defy some entropy laws but what do I know?

https://en.wikipedia.org/wiki/Star_lifting

Re: Nuclear fission fuel is inexhaustible (2022)

#80

Post by jillesvangurp »

PaulKeeble wrote: post #19
jillesvangurp wrote: post #12

The article has a great flow chart in it that highlights rejected energy and energy services and where the rejected energy comes from. energy here spans the spectrum of electricity generation, heating, industrial usage, transport, etc. Basically more than two thirds of the energy is lost to heat, friction, noise, transmission losses, etc. Most of the losses are coal, gas, and oil. Important to note that the image is…

Another aspect is the power it costs to make the power. Oil is a huge industry with enormous transport fuel usage. Nowadays about a 6th of the energy goes into collection. The more we electrify the more that will be saved too coming off the total power we need. Solar, Wind, Hydro and Nuclear are all vastly better in this aspect on production costs and little ongoing transport.

Good point. Oil tankers by themselves put out a measurable percentage of CO2. Also oil refining is an energy intensive industry. Ironically, a lot of that has been cleaned up. It's literally cheaper for oil refineries to be using wind and solar than it is for them to burn their own product. That's why Texas has so much renewable power.
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