Molten Salt Reactors • Hacker News Board

Re: Molten Salt Reactors

#81

Post by jabl » Sat, Jul 13, 2019, 1:49 PM UTC

Reason077 wrote: post #58

Mirioron wrote: post #51

Earlier quoted context omitted.

Renewables have the problem that the larger the portion of your power that's generated through these renewables, the exponentially more storage you need. It's not a linear relationship, because you can have weather that doesn't cooperate for long periods of time, but the power can't go out. Another issue is that solar and wind aren't really suitable everywhere. The further north you go the less economical solar becom…

Solar is getting so cheap that it's becoming economical in places that might surprise you. The UK sits further north than almost all of the USA (excl. Alaska), and has a climate not exactly known for its abundant sunshine. But large-scale solar farms are now commercially viable here without subsidy. (eg: https://www.clevehillsolar.com )

Up here the yearly sunshine is pretty good, close to Germany or so. The problem is that almost all of it comes during the summer. In the winter months when demand peaks, solar produces practically nothing. So without seasonal storage becoming economical, it's not a solution to decarbonizing.

Closer to the equator where seasonal variation is less and demand is driven more by air conditioning than heating solar is an excellent choice.

Re: Molten Salt Reactors

#82

Post by Bluestrike2 » Sat, Jul 13, 2019, 3:11 PM UTC

twic wrote: post #77

wffurr wrote: post #64

Earlier quoted context omitted.

And the environmental costs for nuclear were internalized by regulation, while the same did not happen for coal. This is still well within the realm of economics.

> the environmental costs for nuclear were internalized by regulation, while the same did not happen for coal It very much did happen for coal. That's what this whole global warming business is about.

As far as coal's negative externalities go, carbon emissions and their impact on climate change were only some of the most well-known. There's extensive air and water pollution from both mining and electricity production, with negative health effects for everyone from the miners who mine the coal to those living near the power plants themselves. Mining operations can also have pretty significant environmental impacts in addition to the pollution. Fossil-fuel power plants result in thousands of premature deaths each year, millions of lost workdays, and billions in annual healthcare spending.[0][1][2] And estimates are difficult, so it's easy to undervalue their costs; for C02 emissions, for example, more evidence in recent years suggests that we're drastically underestimating the social and economic damages of carbon emissions.[3]

Very, very few of these consequences have ever been priced into coal-fired power production; for decades, it's been a de facto subsidy. And while we're seeing some shifts needed to lower emissions to fight climate change, many of the identified externalities still aren't priced in. Nuclear energy never received that kind of benefit of the doubt, or the sort of friendly regulatory capture that let society ignore many of its own negative externalities and risks.

0. https://www.scientificamerican.com/article/graphic-science-h...

1. https://www.scientificamerican.com/article/the-human-cost-of...

2. https://journals.plos.org/plosone/article?id=info%3Adoi%2F10...

3. https://news.stanford.edu/2015/01/12/emissions-social-costs-...

Re: Molten Salt Reactors

#83

Post by AnthonyMouse » Sat, Jul 13, 2019, 3:41 PM UTC

pfdietz wrote: post #70

AnthonyMouse wrote: post #35

Earlier quoted context omitted.

Nuclear has effectively zero unit cost, it's all fixed cost. Once you build the reactor, you generate at full capacity all day and night and take whatever the market rate is. That means you get paid less during the day when solar is the cheapest provider, but you still match its price and supply your full generation capacity even then, because you can, because anything is more than nothing and the incremental generat…

"as long as the average price is above average cost" And that's the killer. Add enough solar and wind and the average price craters, even if solar and wind cannot handle everything (without help from dispatchable sources and/or storage).

The problem with that argument is that it proves too much. It applies to everything, because solar and wind are the same as nuclear, their incremental generation cost is effectively zero once the capital is paid, so you take whatever the market price is.

Which means you have a problem.

It's physically possible to build enough solar and wind and storage to even handle extended periods of low sun and low wind. But if you do that then on a normal day with a normal amount of sun and wind, you have a large oversupply and the price falls to zero and everybody goes bankrupt.

That happens less if you add real baseload like nuclear to the mix, because something with a fixed generation capacity doesn't have a periodic shortage requiring you to compensate with an overcapacity which bankrupts everybody on a normal day.

Re: Molten Salt Reactors

#84

Post by URSpider94 » Sat, Jul 13, 2019, 3:43 PM UTC

_0w8t wrote: post #63

ivanhoe wrote: post #55

Earlier quoted context omitted.

The cost of manufacturing energy is not the only cost when you need to distribute energy on a large scale. Electrical grids are prone to oscillations and having less and bigger power sources makes things a lot easier and more reliable (and that means cheaper also). You can store energy but that again increases complexity of the grid and costs (even super-cheap storage will always be more expensive than no storage). T…

Grids must be very stable because there is no storage at the end points. If electricity consumers are very OK to be without electricity for few hours per day that alone makes grid much cheaper.

If every endpoint has enough storage to go days without being online, then that’s going to distribute a very large cost to the edge of the grid. Part of the reason that we have a power grid is so that we can pool usage and build capacity based on overall statistics, no absolute peak.

Additionally, the cost to operate the grid is based upon the size of the distribution network and maximum carrying capacity. If we all build local storage that takes us off the grid 90% of the time, we are still going to have to pay the utility roughly the same amount to maintain the network as we do today. Check your power bill, the generation costs are probably less than half of your monthly total, so the rest is going to come back to you one way or the other.

Re: Molten Salt Reactors

#85

Post by pfdietz » Sat, Jul 13, 2019, 3:46 PM UTC

martinald wrote: post #71

jillesvangurp wrote: post #50

Earlier quoted context omitted.

Yes. Not indefinitely of course but we've seen nothing yet and there's enough in the research pipeline to suggest clear trends over the next two decades in terms of cost improvements, efficiency improvements, cheaper materials, etc. That 4% you mention was less than 1% not so long ago and will be closer to 40% not too long from now. Such is the nature of exponentials. IMHO 5X cost reduction is basically a done deal e…

This is very very optimistic. While the prices of panels are going down the rest of the cost isn't (land, permitting, installation labour, etc). And panels are only a small proportion of the cost now. There is also only so much more efficient the panels can get per sq m. Right now we are approaching 20% efficiency, so the idea that they are going to get 10* cheaper with complete ease seems to be pushing it. Regardles…

All the costs have been falling, at various rates.

It's amusing to see "permitting costs" being presented as a barrier, when at the same time "get rid of regulations" is spouted as the panacea for reducing nuclear's costs.

Re: Molten Salt Reactors

#86

Post by petschge » Sat, Jul 13, 2019, 3:50 PM UTC

jabl wrote: post #81

Reason077 wrote: post #58

Earlier quoted context omitted.

Solar is getting so cheap that it's becoming economical in places that might surprise you. The UK sits further north than almost all of the USA (excl. Alaska), and has a climate not exactly known for its abundant sunshine. But large-scale solar farms are now commercially viable here without subsidy. (eg: https://www.clevehillsolar.com )

Up here the yearly sunshine is pretty good, close to Germany or so. The problem is that almost all of it comes during the summer. In the winter months when demand peaks, solar produces practically nothing. So without seasonal storage becoming economical, it's not a solution to decarbonizing. Closer to the equator where seasonal variation is less and demand is driven more by air conditioning than heating solar is an e…

Closer than 51 North? you mean like all of the continental US?

Re: Molten Salt Reactors

#87

Post by rkachowski » Sat, Jul 13, 2019, 3:50 PM UTC

There's a lot of references to "plate out" in the article and most of the results I find on Google are paywalled by Elsevier - can some explain what the term means or point me to a resource?

Re: Molten Salt Reactors

#88

Post by javier2 » Sat, Jul 13, 2019, 3:53 PM UTC

jillesvangurp wrote: post #32

The elephant in the room with any kind of fission reactor is that they are going to need a lot of security. Even when the fuel and waste product is not weapons grade uranium, it's still highly radioactive and a great source of material for a dirty bomb. Basically anything that goes boom combined with small amounts of radioactive material and a bit of wind is a great way to depopulate e.g. large cities. So, having lot…

You can't run an electrical grid on wind and solar alone and expect it to be stable enough.

- The prospect of every household having a battery backup big enough to smooth over spikes and dips is ludicrously wasteful. We are already struggling just mining enough to make batteries for cars and phones.

- the sheer scale of the wind and solar farms will leave major environmental impact to wildlife. Look at how massive area solar farms need, and know the area has to be cleared and desolate of life.

Re: Molten Salt Reactors

#89

Post by nimish » Sat, Jul 13, 2019, 3:56 PM UTC

The big problem with nuclear driven steam turbines is that they cannot be cheaper than thermal coal driven steam turbines due to costs-- construction, operation and decommissioning. Their LCOE is just not great and not lowering quick enough.

Even thermal coal is getting out priced by solar/wind+ batteries. And the latter will always get cheaper due to economies of scale and learning rate reductions not to mention core technological advances.

Nuclear would have kept us out of the carbon free energy mess decades ago but it's not the answer in 2019.

Re: Molten Salt Reactors

#90

Post by achalhp » Sat, Jul 13, 2019, 4:00 PM UTC

jillesvangurp wrote: post #32

The elephant in the room with any kind of fission reactor is that they are going to need a lot of security. Even when the fuel and waste product is not weapons grade uranium, it's still highly radioactive and a great source of material for a dirty bomb. Basically anything that goes boom combined with small amounts of radioactive material and a bit of wind is a great way to depopulate e.g. large cities. So, having lot…

(Molten salt reactor is a fluid fuel reactor. Fluid: liquid, gas and plasma.)

Molten salt reactor is a stepping stone for fusion reactors. We need to master liquid and gaseous reactors before going plasma. Our civilization should aim for larger goals. We need some form of nuclear power to terraform other planets and spread earth's precious life and conciousness everywhere.