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Nuclear energy is clean

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Re: Nuclear energy is clean

#691

Post by pfdietz »

pfdietz wrote: post #457
replygirl wrote: post #319

Earlier quoted context omitted.

the delta project is primarily a natural gas plant for the next 25 years, btw

They might be using SMR hydrogen to start with, for demonstration purposes, but doing it with SMR at scale would make absolutely no sense; it would be cheaper and more efficient to store and use the natural gas directly.

Ah, I see. You are referring to the turbines burning a 30% H2/70% NG initially. They are still using electrolyzers to make the hydrogen. Going to turbines that burn 100% H2 is not a huge technical obstacle. There are already turbines burning hydrogen, so hydrogen combustors are feasible.

Re: Nuclear energy is clean

#692

Post by elproxy »

jokoon wrote: post #351
cycomanic wrote: post #289

This article perfectly exemplifies the arguments in discussions. Lets just concentrate on the waste discussion. The article says heavy metals in solar panels are a problem (I kind of agree, although the way it is described makes it out like we are talking about huge amounts, in reality the lead in solar panels is largely from soldering so very small amounts. Orders of magnitude more are being used for other applicati…

Renewables are not baseload. If you add batteries to the mix, nuclear is better. Not to mention the quantity of power produced. Nuclear is expensive because it's long term investment. Renewables also cost more in resources (concrete, steel, copper), there are sourced charts about this. Renewables are better than coal and gaz, but not better than nuclear. There's nothing wrong with renewables, but it's not enough to o…

Nuclear is expensive first and foremost because of the unreasonable yield demands of capital and the advent of neoliberalism causing states to cave to said demands (source: https://www.nao.org.uk/wp-content/uploads/2017/06/Hinkley-Po...)

Re: Nuclear energy is clean

#693

Post by loup-vaillant »

Krasnol wrote: post #653
loup-vaillant wrote: post #637

Earlier quoted context omitted.

Those things in the middle do sound risky. But what's the alternative really? What energy do we have that (i) scales, and (ii) comes at will ? Right now that's mostly nuclear and fossil. Now there's this thing called "global warming", caused by fossil fuels. That thing is poised to displace billions of people as parts of the planet becomes unfit for human life. That means wars, famine, and disease, whose scale will i…

> Those things in the middle do sound risky. But what's the alternative really? What energy do we have that (i) scales, and (ii) comes at will? Right now that's mostly nuclear and fossil. No. That's just a proper grid with renewables. It works already within the single market of the EU. > Now there's this thing called "global warming", caused by fossil fuels. Yeah we've heard of it. Actually the country which is most…

> You did get the news that it's just another year where France needs to turn off their nuclear fleet because their rivers get too hot?

Yeah, in retrospect we should have put more plants around our coastlines.

> The topic "nuclear and global warming" is a straw man. It makes no sense at all.

Okay let's start over. We need to somehow reduce our emissions down to near zero. No oil, no gas, no coal. That leaves renewables (wind, solar, geothermal, hydro, forest wood), and nuclear. And energy savings.

Among all those, what can scale, at what cost, and what can we do with those? Hydro is maxed out in many parts of the world, geothermal doesn't work everywhere, forest wood is probably maxed out already (we can burn more, but it would cease to be renewed). That leaves wind, solar, and nuclear. With current tech, nuclear is the thing that takes the least concrete, the least real estate… and with the exception of regular maintenance and hot rivers delivers its full power at will.

Wind and solar however not only cost way more (per energy unit), they only deliver when the sun shines or the wind blows. In practice this puts a significant strain of the network. There are 3 ways to compensate for that: nuke plants, energy storage, and cutting off non-essential power.

Thing about nuke plants is, they're not less expensive when they run at less than full power. Beyond a certain point, more renewables doesn't need less nuke plants. It means just as many nuke plants, running below capacity. Having any more than that would be pure waste. One huge disadvantage however is that they're very capitalistic: we need a huge investment to make a single plant, and that requires a very stable political environment (a similar argument works for nuclear waste).

Energy storage is currently very expensive. It's nice to have some (like hydro dams), and it does mean that we can reduce the nuke installed based accordingly. But building huge swaths of batteries or flywheels may be much more problematic.

Finally we could cut-off non-essential power. I'm not entirely against that, but we need to keep in mind that this is not exactly a painless change (I do like my comfort).

Of course, we could mix the 3.

Re: Nuclear energy is clean

#694

Post by ETH_start »

pfdietz wrote: post #665
ETH_start wrote: post #606

Earlier quoted context omitted.

Nuclear power is the cheapest option: https://www.oecd-nea.org/lcoe/ And it is far more reliable than renewables.

That's for "LTO": extending the lifespan of existing nuclear plants. The cost of power from new construction nuclear would be much higher.

The LTO is the estimated lifespan of the plant. The LTOs provided in that chart are well below the real lifespan of these plants.

The capital cost of building the plants is also provided in the chart. That means this accounts for "the cost of power from new construction nuclear" you refer to.

Re: Nuclear energy is clean

#695

Post by Krasnol »

loup-vaillant wrote: post #693
Krasnol wrote: post #653

Earlier quoted context omitted.

> Those things in the middle do sound risky. But what's the alternative really? What energy do we have that (i) scales, and (ii) comes at will? Right now that's mostly nuclear and fossil. No. That's just a proper grid with renewables. It works already within the single market of the EU. > Now there's this thing called "global warming", caused by fossil fuels. Yeah we've heard of it. Actually the country which is most…

> You did get the news that it's just another year where France needs to turn off their nuclear fleet because their rivers get too hot? Yeah, in retrospect we should have put more plants around our coastlines. > The topic "nuclear and global warming" is a straw man. It makes no sense at all. Okay let's start over. We need to somehow reduce our emissions down to near zero. No oil, no gas, no coal. That leaves renewabl…

> That leaves wind, solar, and nuclear. With current tech, nuclear is the thing that takes the least concrete, the least real estate… and with the exception of regular maintenance and hot rivers delivers its full power at will.

But takes the most time, cost hilarious amounts of money, creates waste for generations and is just another finite resource energy generation technology from the past.

This is not what we need to reduces our emissions down to near zero now. We need technology which is cheap, deployable before it is too late to reduce our emissions and accessible for every country on this planet. This technologies are renewables and only those.

So please...if you really care about the environment and are not merely one of those people who blindly recite Michael Shellenbergers Astro-Turf campaign, don't mention nuclear on this topic again. It doesn't make any sense.

> Thing about nuke plants is, they're not less expensive when they run at less than full power.

Think about nuke plants is, they're least expensive when they are turned off. Even the grid profits from that since you don't have that expensive nuclear crap clogging up the lines so cheap renewable energy generation has to be turned off.

Time to face it: nuclear is done....at least in the civil sector.

Re: Nuclear energy is clean

#696

Post by Krasnol »

tekknik wrote: post #681
Krasnol wrote: post #673

Earlier quoted context omitted.

> Renewable's are amazing, the more the merrier. But discarding nuclear over it's waste isn't a genuine argument. How isn't it when it actually is in Germany? > We've gotten better than the 60s/70/80 when old plants were built How so when the waste from those reactors is still stored next to those reactors? > That shouldn't stop us from pursuing cheap energy. Nuclear is not cheap. > We also know how to use solar, win…

> Nuclear is not cheap. It’s getting cheaper. The primary reason it’s not cheap currently is every reactor built is site specific. This will soon change with smaller reactors being built in factories then installed. > Something you can't say about nuclear. A technology from the past. This seems like an attack again on nuclear. Stars use nuclear reactions for energy, you’re alive because of a nuclear reaction. Why are…

> It’s getting cheaper.

I'm looking forward to those sources on that bold claim.

> This will soon change

...and I hope that claim was not based upon that wishful thinking but on actual facts which are valid today.

> Stars use nuclear reactions for energy, you’re alive because of a nuclear reaction. Why are you so quick to throw it out?

Nobody wants to turn off stars. This is a unnecessary derailment.

And we're quick to throw it out because the money needs to go into renewable technology which can be deployed fast and cheap to face the current global crisis.

> What do these people do for power? I can’t put a wind turbine on the roof of my apartment anymore than a solar panel

What do these people do if they want to eat a hamburger? Do they all have a cow in their basement? I mean seriously...what is this?

> Once we solve the energy problem, population growth is our next one....

I don't even...

Re: Nuclear energy is clean

#697

Post by onethought »

ETH_start wrote: post #683
onethought wrote: post #676

Earlier quoted context omitted.

To completely replace fossil fuel, you need a lot of nuclear plants and nuclear materials and transmission lines. For renewables you can handle a lot of the load near the consumption point and only need to transmit the “night load” which is usually much less.

I recommend you look at the estimates on how much storage and/or transmission lines are needed to go full renewable.

How many nuclear plants are required to go fully nuclear? I haven’t seen those estimates at all which is interesting

Re: Nuclear energy is clean

#698

Post by credit_guy »

pfdietz wrote: post #686
credit_guy wrote: post #684

Earlier quoted context omitted.

All things being equal TRISO fuel should increase the waste volume. But a fast reactor will tremendously reduce both the waste volume (because it can burn U238) and its nastiness (it will have virtually no long half life actinides). As for steel. Steel is one of the cheapest materials, with an average price below $1000/ton. Nuclear reactors need to use special steels that are resistant to neutron embrittlement, and e…

Does TRISO have higher burnup? Not convinced. Fast reactors that involve reprocessing will greatly increase waste volume due to generation of low level contaminated material in the reprocessing process. Once you let the stuff out of the fuel elements it can get all over things.

Nothing to do with reprocessing.

Fast neutron reactors just use fast neutrons, neutrons that are thousands of times faster than the neutrons used in the current generation of reactors (called thermal neutrons). A thermal neutron is much more likely to hit a nucleus of Uranium. If it hits U-235, it generally makes it undergo fission, but 18% of the time it is just absorbed and becomes the nasty U-236, which is a very long lived radioactive element. If it hits U-238, it's absorbed, eventually becomes Plutonium-239, which in turns may absorb further neutrons, so a bunch of transuranic elements are produced.

That's bad on two counts. The transuranic elements are radioactive and tend to be very long lived so the nuclear waste is long lived. And whenever a nucleus just absorbs a neutron and does not undergo fission, it's a shame, it's energy that's not being produced.

Fast neutrons solve both problems. They are about 1000 times less likely to hit a nucleus, but when they do they almost invariably trigger fission for U-235 and very often for U-238 as well. That results in a massively higher burnup, and massively lower amount of transuranic elements in the waste.

So, not only will a fast reactor produce much less waste for each GWh of electricity, it will be a much nicer type of waste, one that decays to the background radiation level in a few hundreds of years, rather than millions of years.

Again, there is no reprocessing. The TRISO particle are not broken or milled at the end. They become nuclear waste as they are, but after they gave a huge amount of energy.

Re: Nuclear energy is clean

#699

Post by pfdietz »

credit_guy wrote: post #698
pfdietz wrote: post #686

Earlier quoted context omitted.

Does TRISO have higher burnup? Not convinced. Fast reactors that involve reprocessing will greatly increase waste volume due to generation of low level contaminated material in the reprocessing process. Once you let the stuff out of the fuel elements it can get all over things.

Nothing to do with reprocessing. Fast neutron reactors just use fast neutrons, neutrons that are thousands of times faster than the neutrons used in the current generation of reactors (called thermal neutrons). A thermal neutron is much more likely to hit a nucleus of Uranium. If it hits U-235, it generally makes it undergo fission, but 18% of the time it is just absorbed and becomes the nasty U-236, which is a very…

TRISO fuels may have higher burnup, but they also have large dead volume in the fuel elements. The fissionable material is surrounded by barrier layers, and these encapsulated particles are embedded in a non-fuel matrix. The volume of spent pebbles will I think be considerably larger than the volume of spent fuel elements from a conventional reactor per unit of produced thermal energy.

Re: Nuclear energy is clean

#700

Post by pfdietz »

ETH_start wrote: post #694
pfdietz wrote: post #665

Earlier quoted context omitted.

That's for "LTO": extending the lifespan of existing nuclear plants. The cost of power from new construction nuclear would be much higher.

The LTO is the estimated lifespan of the plant. The LTOs provided in that chart are well below the real lifespan of these plants. The capital cost of building the plants is also provided in the chart. That means this accounts for "the cost of power from new construction nuclear" you refer to.

LTO is referring to refurbishment efforts to extend the lifespan of an existing plant.

Look at the first line in that chart. It's for 20 years of operation of a 1000 MW reactor. The capital cost is listed as $5.93/MWh. If that reactor is operating at 90% capacity factor for 20 years, the total capital cost comes in at less than $1B. That cannot possibly be the cost of building a new nuclear plant. Instead, it's the capital cost of the refurbishment needed to allow an existing reactor to operate for another 20 years. This can surely be a nice way to get more from many existing NPPs (although some of these refurbishment efforts have gone disastrously wrong; see Crystal River 3 in Florida for example), but it has little relevance to the cost of building a new NPP.

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