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Comment by floppiplopp | Hacker News Reader

What's always missing in these kinds of propaganda articles is the resource issue with fissile material. If you look at the data given by the International Atomic Energy Agency you'll see that there are roughly 6 million tons available at the moment, with the price for uranium doubling over the last 20 years and cost for exploration quadrupling in the same time. Now, we get around 10% of all energy worldwide from fission, using 60k tons of uranium per year. So, at the current rate, we can do this for maybe 100-150 years. Increase the power output, reduce this time accordingly. And don't mention non-existing or experimental reactors like fusion of thorium, that have been just 10 years away from working for the last 50 years. We cannot solve climate change with current nuclear energy technology. There's just not enough fissile material.

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Yes, but..... It emits a lot less greenhouse gas right? Even if we only have 100-150 years, that is a long time horizon for us to figure out nuclear fission which doesn't use uranium.

Our current problem is that we need energy, and we currently have several ways of producing it several of which produce much more green house gas than others. Nuclear looks like a less than ideal solution, but one that we know how to do today, and one that can replace coal/gas in the interim buying time while we get other tech ready to go.

The embodied energy problem with nuclear plants is nothing to laugh at.

The barrier for getting new plants up is going to increase as we tackle the carbon footprint of concrete. At least until someone certifies these new concretes for building nuclear plants.

Nuclear energy offers an excellent source of energy for the production of concrete. I can imagine that a new plant would not take very long for it to offset enough CO2 to make up for the CO2 used in its production. Similar to electric cars and solar panels.

My understanding was that the processes for replacing fossil fuels in the redox reactions for making cement are still being worked on. Last I heard, one or two companies have rolled one or two of these processes into production, and everyone else is playing wait and see or doing R&D.

Some cement plants are reducing their emissions by including fly ash into their mix, and as coal plants wind down across the world, I don't know what other waste streams there are to backfill that, or if in the near term removing coal from our energy mix actually amplifies the percentage of our overall carbon footprint represented by concrete.

Only about 50% of the CO2 emissions from standard concrete production are an unavoidable byproduct, the rest are from energy generation and transportation. Currently only 8% of CO2 generation is from Concrete. Replacing coke and natural gas as heat sources would reduce that to about 4%. Electricity and heat make up 30%. Transportation is another 15%.

I think the target is a 60% reduction. If we can replace electric generation, half of concrete, and transportation that would account for about 49%. The rest is agriculture and methane which are their own headaches.

Concrete is probably one of the last things on our CO2 emission hit-list. Kind of an extra credit compared to power generation and transportation.

https://www.c2es.org/content/international-emissions/#:~:tex....

> Currently only 8% of CO2 generation is from Concrete.

So I have this conversation with coworkers all the time. Thinking in fractions of the status quo is a logic trap, and most of us fall into it.

As Gretzky famously said, "skate to where the puck is going to be."

We need to halve our CO2 emissions. That means concrete is 16% of the target. That is way too large of a fraction to ignore. We will not get where we are going if we don't look at this, and hard. 1/6th of our target is practically a call to action. 8% is more likely to invite foot dragging.

If you lose your job and have to change careers, it doesn't matter if your fancy car is 12,15,18% of your current monthly expenses. What matters is that it's now 40% of what you have available to spend, and you simply cannot be spending that much on a car. Getting rid of the car is more important that weening yourself off of a daily Starbucks run, steaks, or starting to use coupons.

We cannot be spending 1/6th of all carbon output on concrete. Especially if we're going to make suggestions that involve huge increases on concrete usage.

I wish as a species we could all wrap our heads around this. It gets really old explaining to people that they need to look at the thing that is taking 5% of run time because it's "only 5%" when rationally it should be using .25% of resources and thus it's taking 20x as long as it has any right to be. They won't look at it until overall runtime is down 25% and now we are creeping up on double digits. It's a delaying tactic, and we can't wait for other people to do their part before we start on ours. These are not ordered lists.

The CO2 cost of creating nuclear power plants from concrete is a drop in the bucket compared to the 30-45% of CO2 emissions from power generation and transportation that needs to be replaced as soon as possible. Especially since it will be a remarkably small percentage of overall concrete usage.

Concrete isn't negligible, however the unavoidable 4% of emissions for standard concrete isn't enough of a deterrent to require us to curb its use in favor of other methods immediately. Especially considering it's utility. With enough carbon free energy we could offset that 4% very easily. In the same way we can create carbon neutral fuels with sufficient cheap energy.

Can we stop shallowly dismissing anything we don’t agree with as propaganda?

1. Breeder reactors can be used to massively increase effective fuel efficiency.

2. Uranium can be extracted from seawater (virtually limitless) at an estimated cost of 2 cents/kWh

3. Renewables have even more stringent metals and rare earths requirements

Re 1 - it really is quite astonishing how uninterested nuclear plants seem to be in burning their fuel.

It makes perfect sense if you consider the original reasoning - to make weapons, then progressively adapted to make them less useful for making weapons.

Still, I can't help but feel that fans of this mythical "innovative private sector" have a lot to answer for. Here's a 100-fold optimization in fuel use - not in fact a trivial cost, even for nukes - that's been on the table for more than fifty years, with the only drawback that nobody has literally given you the schematics. Now we're burning a shit-ton of gas and funding the tanks for the privilege.

Well, the fuel is only like 20% of the cost of nuclear power, with the majority being capex, so there’s really little reason to build even more expensive reactors with more regulatory issues to save on opex which isn’t even significant.

Opex "isn't significant" only in comparison to capex for nukes. Nukes' opex is, like capex, outrageously huge compared to both for renewables. Every penny spent on building nukes instead of building out renewables/storage adds to global climate disruption.

And thorium is in much greater supply than uranium

A resource issue is what you worry about in 100-150 years? That’s laughable considering our planet might not be actually livable as we know it if we conduct business as usual. And that isn’t propaganda. It is a fact, and nuclear is utterly necessary to stave off the worst.

It's not yet done outside of a lab setting but we can extract virtually unlimited uranium from seawater https://www.forbes.com/sites/jamesconca/2016/07/01/uranium-s..., Since the uranium in seawater is naturally replenished it could be as sustainable as wind or solar and would only add fractions of a cent per kWh to the cost of energy generation.

We don't currently refine "spent" nuclear reactor fuel, in the US at least, which still contains significant amount of fissile material. When the fuel is "spent" we really just mean that the amount of fissile material is too low to sustain the nuclear reaction needed to collect energy. We would get more energy out of our uranium if we did, but instead we just let it become waste. Russia is very good about refining their uranium for nuclear power. We don't do it in the US for nuclear proliferation reasons. I'm less certain about the rest of the world on this though.

We don't refine waste because it costs more than refining mined uranium. Which itself costs a lot.

Everything around nukes is massively expensive -- building, fueling, operating. To the extent they steal money from building out renewables and storage, everything spent on them only adds to the climate crisis.

If we're talking about the limit on the global supply only lasting us about 100 years, then it's irrelevant that it costs more now because the point is fissile material still exists and is a viable source for more energy beyond what the OPs projection was.

What is irrelevant is that fissile material is still available at enormous cost when the alternative, not paying for it, yields much more available power output.

There is usable fuel in every spent fuel pool in America. The Carter admin stopped fuel reprocessing so this fuel just sits there.

What's missing in these kinds of propaganda takes is that:

a) The cost of fuel is currently so low as to be practically zero. Fuel cost does not materially affect the cost of a nuclear power plant.

b) The basic reason for this is that they use so little fuel, because the fuel is so incredibly energy dense, last I checked > 1 million times more dense than fossil fuels. This is essentially impossible to grasp intuitively, which is one of the reasons there are so many completely wrong takes on this topic. See: https://xkcd.com/1162/

c) One result of the fact that fuel is so cheap, practically, is that we currently throw away 95% of the fuel after use. Because it's not worth the effort to actually use all of it.

d) One upshot of throwing away most of the fuel is that we also throw away the fuel that current reactors generate in production. Alas, those are also the nastiest fission products. This is not some far away technology, we have been doing this to get fissile materials for atomic weapons for almost a century now. And we have been repurposing fissile material from nuclear warheads since at least the early 2000s (might have been late 1990s).

e) So if we were to simply use all the existing fuel, we could do "this" for another 20x 100-150 years, so 2000-3000 years. The reason we are not doing this is that it's not currently economically viable, fresh Uranium is just too cheap, and since the political landscape is so irrationally negative there is no incentive for investing when current fuel reserves are sufficient for the current reactors.

Fuel supply and waste are political problems, not technical ones.

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