471–480 of 536 posts
Earlier quoted context omitted.
Do you have a source on that low cost?
https://pv-magazine-usa.com/2020/07/03/nrel-study-backs-hydr...
2050!!!
By 2050 we'll also have Fusion and other mythical power sources.
Earlier quoted context omitted.
Nuclear has had 70+ years and untold zillions in government research money and subsidies poured into it[1] - if the same level of investment over time had gone into renewables, imagine where they'd be now. [1] worldwide - germany, uk, canada, france, russia etc in addition to the us - everyone did build their experimental gas/molten salt/fuel recycling/pebble bed etc reactor research programs and reactors. not to men…
Germany alone spends ~$1.2 trn (that would be ~4.8trn on a population adjusted basis for the USA) on the Energiewende, and Germany is far away from being 100% renewables. The EU now plans to invest another trillion € till 2030. A lot of money is poured into renewables.
Earlier quoted context omitted.
Counterpoint: why is environmental impact of solar+batteries often not mentioned? Lithium, silicon tetrachloride, hydrochloric and hydrofluoric acid isn't exactly nice to produce or put into rivers. My 2c: have an "all of the above" approach towards research, dispassionately understand pros and cons and big-picture complexity, instead of retreating to tribes that ignore the complexity.
None of those are persistent environmental poisons, or need be released into the environment. BTW, I believe hydrofluoric acid is not used to make silicon PV cells.
https://pv-manufacturing.org/acid-texturing/
https://pv-manufacturing.org/alkaline-texturing/
Since the industry is rapidly shifting to monocrystalline silicon, for reasons of cell efficiency, acidic etching too will be much less common in 2025 than it was in 2015.
Of course the use of HF is not a knock against solar. Nuclear fuel production also uses HF as well as elemental fluorine. Petroleum alkylation units use HF too. In all these cases the HF is part of the production process but is not present in the final product.
Earlier quoted context omitted.
One point that's commonly missed in the lay discussions is that the stuff with a really long half-life (e.g. uranium/plutonium) is not that radioactive/harmful; by definition if it takes you 100k years for 50% of your unstable nuclei to decay, the emission rate per second is very low. In contrast, the really nasty stuff has a very short half-life, and emits radiation at a very high rate for a very short duration. The…
>do something safe with the potentially weapons-grade plutonium Reprocessed plutonium from a civilian power reactor would never be weapons-grade, it has too much Pu-240 in it: https://en.wikipedia.org/wiki/Reactor-grade_plutonium It is claimed that it is possible to make weapons from reprocessed plutonium, but the warheads would need active cooling and exotic pit geometries, making them not so amendable to miniaturiz…
Do you have any insight/thoughts on why the US made this push to prevent reprocessing, if it's not actually possible to use that process to build a warhead? Is it possible that they discovered a pathway in their nuclear tests that has remained classified? Or could it be an error/overly cautious policy position that just hasn't been updated since the '70s?
Earlier quoted context omitted.
Indeed, reprocessing with PUREX and only using thermal reactors will most likely never make any economic sense. Breeder reactors and more economic and proliferation-resistant reprocessing technologies like pyroprocessing might, however. Too early to tell really, as neither have really been developed to the point where one can make precise economic predictions.
But breeders themselves are uncompetitive (and fast breeders are inherently dangerous, since they require much higher concentrations of fissionable material, and could potentially experience fast prompt supercriticality in severe accidents.) If nuclear is not competitive with cheap uranium and burner reactors, it's not going to be competitive with breeders and reprocessing.
Hard to say. Hasn't really been commercialized to the point one could make any definite conclusion. There's nothing inherent in a breeder reactor that would make it substantially more expensive.
> and fast breeders are inherently dangerous, since they require much higher concentrations of fissionable material, and could potentially experience fast prompt supercriticality in severe accidents.)
No. In a fast reactor the prompt neutron multiplication time is an order or magnitude faster than in a thermal reactor, but still several orders of magnitude slower than in a weapon. Further, the enrichment is much lower than in a weapon (recent-ish designs are made to work below the 20% HEU limit for obvious reasons), so it's quite unclear if it's even possible to get all the material into a suitable geometry before it would blow itself apart.
Of course it's possible to have a criticality excursion that would destroy the reactor, but those are possible in thermal reactors as well.
> If nuclear is not competitive with cheap uranium and burner reactors, it's not going to be competitive with breeders and reprocessing.
The fuel cycle costs are basically fuel + enrichment + disposal for a once-through thermal cycle, and fuel + reprocessing + disposal for the breeding cycle. Fuel and disposal costs would be lower for the breeding cycle, although with current prices and maturity level of the technology you're correct that the once-through cycle is cheaper. Not written in the stars that it will remain so forevermore, though, and breeder + reprocessing tech is waiting in the drawer for that day, in case there ever will be a need. No hurry.
Two interesting things to see here, of many. They are really planning the sites to be temporary compared to the solar/wind/ and other industrial power plants that have little or no plan for returning their sites to the original virgin soil. And two, they seem to use a molten salt loop like in concentrated solar to meet variable demand without changing the power level of the reactor, which you can't really do because…
And unlike a natural gas plant, it costs 3-10x what the equivalent generating capacity in renewables would cost. I come to post this Same Thing every time this discussion comes up. It's not about safety. Everyone serious understand nuclear, even current technologies, is "safe enough" to be useful to build out. Nuclear is outrageously expensive , though. And new reactor designs don't seem to be making much progress on…
Earlier quoted context omitted.
>do something safe with the potentially weapons-grade plutonium Reprocessed plutonium from a civilian power reactor would never be weapons-grade, it has too much Pu-240 in it: https://en.wikipedia.org/wiki/Reactor-grade_plutonium It is claimed that it is possible to make weapons from reprocessed plutonium, but the warheads would need active cooling and exotic pit geometries, making them not so amendable to miniaturiz…
Thanks, I wasn't aware of that detail. This makes the anti-proliferation position of the US from the '70s to this day even more perplexing. Do you have any insight/thoughts on why the US made this push to prevent reprocessing, if it's not actually possible to use that process to build a warhead? Is it possible that they discovered a pathway in their nuclear tests that has remained classified? Or could it be an error/…
"Additional Information Concerning Underground Nuclear Weapon Test of Reactor-Grade Plutonium"
https://www.osti.gov/opennet/forms?formurl=document/press/pc...
A successful test was conducted in 1962, which used reactor-grade plutonium in the nuclear explosive in place of weapon-grade plutonium. The yield was less than 20 kilotons.
This test was conducted to obtain nuclear design information concerning the feasibility of using reactor-grade plutonium as the nuclear explosive material. The test confirmed that reactor-grade plutonium could be used to make a nuclear explosive. This fact was declassified in July 1977. The release of additional information was deemed important to enhance public awareness of nuclear proliferation issues associated with reactor-grade plutonium that can be separated during reprocessing of spent commercial reactor fuel.
The Carter reprocessing ban was enacted in April 1977, a few months before this information was released to the public.
There is no evidence that any existing nuclear weapons state has started with plutonium reprocessed from civilian power reactors. Building "production" reactors that produce plutonium without generating electricity is easier and the plutonium quality is higher. However, reprocessing commercial fuel is a potential loophole for nations that want to maintain a latent nuclear weapons capability as a plausibly deniable part of a civilian nuclear power program. There are indications that Japan values its reprocessed plutonium from civilian reactors in this light.
More pointedly, would Saudi Arabia, Israel, or the US trust an ostensibly civilian Iranian nuclear power program that included plutonium separation and reprocessing? Would Iran trust a Saudi program of the same type?
The high Pu-240 content of spent nuclear fuel from commercial reactors is not a strong enough technical barrier against weapons use to be reassuring in circumstances of low initial trust between parties. That's why it makes at least some sense that the United States did not want reprocessing to be a routine feature of civilian nuclear power programs.
========================
EDIT: everything following this line ^ is very speculative, so take with a shaker of salt. But I think it's an interesting idea that I haven't seen anyone else write about.
There are some exotic chemical reactions that give rise to mass-independent isotope fractionation [1]. For isotopes subject to this effect, enrichment can be more efficient via these mass-independent effects than would be indicated by conventional mass-dependent enrichment mechanisms like gas diffusion or centrifuge enrichment. There is evidence that these effects apply in uranium. The behavior is to separate even and odd isotopes rather than heavy and light isotopes [2].
If a similar mass-independent enrichment process were discovered for plutonium, it would mean a couple of things:
1) It might be industrialized secretly, in the context of weapons, long before it becomes a publicly known process with corresponding anti-proliferation safeguards and targeted inspections.
2) It would mean that aged spent nuclear fuel from commercial reactors could become an excellent raw material for making weapons plutonium. The other major contaminant isotope, Pu-241, has a half life of only 14 years. A few decades of cooling largely eliminates it. Then the Pu-240 would be separated from Pu-239 by the mass-independent fractionation process.
[1] https://en.wikipedia.org/wiki/Mass-independent_fractionation
[2] https://link.springer.com/article/10.1007/s11631-016-0109-3
Earlier quoted context omitted.
And renewables are cheap because peaker plants exist, which allows the price of storage to be externalized to the peaker plants.
Well, you also have to consider that many gas plants emit less CO2 than coal plats. You're going to need them either way because it's the fastest way to reduce the CO2 footprint of your nation's electricity mix.
Earlier quoted context omitted.
>Burn the hydrogen in combustion turbines, just like natural gas. That simple? Anyone in the world actually using hydrogen in this way? You can dissmis nuclear all you want, but doesn't change the fact that renewables (outside of hydro/geothermal for which you need special geography) do not work. There is no nation on this planet that is powered by renewables. There is no nation on this planet that is planning to be…
> That simple? Anyone in the world actually using hydrogen in this way? https://www.ge.com/power/gas/fuel-capability/hydrogen-fueled... "Our turbines have nearly 30 years of experience operating on a variety of fuels that contain hydrogen, totaling over 6 million operating hours as hydrogen-fueled turbines using concentrations ranging from 5% to 95% (by volume)." > You can dissmis nuclear all you want, but doesn't ch…
>Ah yes, the old "nothing can ever happen for the first time" argument. Mindless reactionary nonsense.
The problem for you is that renewables have been around for years so the fact that they aren't powering any economy needs an explanation. Furthermore, even conceptually, you haven't explained HOW they would power an economy. Renewables have well known limitations. They are diffuse power sources, require huge surface areas covered with high-tech collectors, and are highly variable. The only way we can get them to work is by attaching them to a grid with natural gas or coal - because we have no way to store excess energy enough to bridge their variability. You can deny this, but it is an actual fact and the fact that you cannot point me to a region that has solved this should be quite telling.
Earlier quoted context omitted.
Only residential has fixed prices for electricity over the day. Industrial electricity has always been sold in variable prices, e.g. furnaces and other large consumers run when power is cheap and go into hold mode when it is expensive. There even is a large discount if you allow the power company to switch your consumption on/off. All that is already a reality and has been for decades. Which goes to show: there still…
But still "base load" is no law of nature. Half the market is on fixed price, and regulation has so far dictated that there has to be a lot of "base load" type power production, and without co2 externalities priced in that's been profitable for producers too. But it's all rules and tech we invented and can be changed. The amount of supply following the current industrial users are incentivised to do, and the requisit…
It's a term that means we can guarantee a set amount of power regardless of environmental conditions. Renewables are sensitive to environmental conditions, and we don't have a battery technology to bridge renewable variablity and hence the need for 'base-load'. In that context, 'base load' is a law of nature.