Hacker News Reader

Comment by rsj_hn | Hacker News Reader

Yes, this country should be covered in nuclear plants that provide the majority of our electricity. Energy should be too cheap to meter. Whatever problems we as a society may have, it will take energy to address those problems, and the core of our energy production has to be stable and reliable.

View on HN

I had a conversation with a co-worker who used to work for Toshiba heavy industries on their nuclear stuff - he made the interesting point that there's only so much accessible uranium on the planet, to the point where we'd use up all of it in ~75 years if we were running the entire planet on nuclear. The only way around this is to use breeder reactors, which is a huge no-no from an international relations perspective because those are the same types of reactors used to make nuclear grade fissile materials.

Honestly that seems like a more easily solvable problem than what to do with ~30 billion solar panels and the corresponding battery capacity that would need to be built up if we tried to get the bulk of the world's energy from solar. Of course when someone points out that there isn't enough raw material to make all those batteries and panels, the standard answer is "we'll mine more", but strangely that's not supposed to be an option with mining uranium -- so I am generally skeptical of the "peak uranium" theories. It's not even a matter of needing to turn to breeder reactors, although that's certainly a possibility, but rather it's just a question of mining more, and that always happens as technology improves and demand for a metal increases.

But sure, nuclear power is not something that would work for every nation on earth. But it would certainly work well for North America and the EU, as well as China, India, Australia, and Japan, which together account for the majority of the world's energy needs.

Your co-worker may be mistaken. ~75 would only make sense if he was saying of known deposits. And even then, there is about 50 million tons of known deposits, and the currently open mines only account for about a tenth of that... I'm not sure we'd need to burn through the resulting refined product of 50 million tons of pitchblende to run the entire planet for 75 years.

This also ignores the rest of the intended refinement chain: thorium and other reactor fuel sources.

The uranium deposits are a long way from 1:1 with fuel grade uranium. Natural ore is generally under 20% uranium, and that uranium is 90.3% U238, and 0.7% U235. Reactors want ~5% U235 but depleted uranium is still 0.2% to 0.3% U235. Which means your produce less than 10% fuel grade uranium from every ton of natural uranium. Ex: Cigar Lake with ~217 million pounds (99,000 t) of ore at 18% uranium is only going to produce ~1,700t of reactor grade uranium. As you very roughly get 1GW for 1 year from 1t of reactor grade fuel that’s only 23GW for 75 years.

Aka, those 50m t of ore globally work out to around 0.5-1m t of fuel though we’re extracting the cheapest stuff first so expect prices to rise well before you extract all of it. There are also options to extract vastly more energy from that same ore, but again they all make nuclear more expensive.

> Reactors want ~5% U235

Light-water reactors, which are the more/most prevalent design. Heavy-water reactors, like CANDUs, can use non-processed uranium in 'natural' concentrations:

* https://energyeducation.ca/encyclopedia/CANDU_reactor

* https://en.wikipedia.org/wiki/CANDU_reactor#Purpose_of_using...

The heavy-water is deuterium oxide, where there "hydrogen" atom has one proton and one neutron, whereas the far more common hydrogen has no neutrons in the nucleus:

* https://en.wikipedia.org/wiki/Heavy_water

Current CANDU reactors are significantly more expensive to operate and have had relatively low capacity factors. Which is why they have had little success outside of Canada. China for example only uses 2 and has abandoned the design. https://en.wikipedia.org/wiki/CANDU_reactor

They do use up to 30% less mined uranium as your link points out, but also produce a lot more high level nuclear waste.

Hmm, that might be right then. I was doing the fuzzy math in my head on what we can do, not what is worth doing right this moment due to market influence.

Conventional reactors also produce plutonium; in fact, there's a suspicion that one reason Chernobyl was so poorly designed (e.g. lacking a containment dome) was that they were extracting warhead fuel from it. About a third of the energy in US reactors is actually from fissioning plutonium, but they do that inefficiently so plutonium and other transuranics make up most of the long-term radioactivity in high-level nuclear waste.

On the other hand, breeder reactors don't necessarily make weapons-grade material. The Integral Fast Reactor in the US produced a mix of four plutonium isotopes, which was totally unsuitable for weapons, and harder to enrich to weapons-grade than natural uranium.

Using breeders multiplies the energy from uranium ore by a factor of a hundred. With such low fuel consumption, it also makes seawater extraction pretty easy, which extends our fuel supply to many millions of years.

This is an interesting point. Is there some data to use as a reference for it? Would other forms of nuclear fuel replace uranium in larger quantities?

I feel like this has been absent in many pro-nuclear arguments (I always assumed we had much more)

There's "uranium in the planet" - lots! - and "uranium accessible to humans" - not so much.

The other fuel used would be plutonium and thorium, I believe. My understanding (not a nuclear scientist) is that there's a cycle of enrichment and decay that produces more fissile materials than it consumes.

Interestingly, from my perusal of wikipedia, it seems like you effectively can recycle the uranium isotopes indefinitely in such a reactor, as well as generating fissile plutonium and thorium.

Again, the problem is that generating fissile plutonium is how you make a bomb

I think China is testing a thorium reactor now. https://www.nature.com/articles/d41586-021-02459-w

China is leading the way, both in terms of adding coal capacity right now to address the power outages while also building out nuclear capacity for the future.

The ability to act rationally like this when popular movements turn irrational is one advantage of an authoritarian system. No doubt many in the west are looking somewhat enviously at China.

Except coal has gotten super duper expensive, and most Chinese coal plants are designed to burn high grade coal such as produced in Australia. Many can’t run at all on the much more common lower grade coal that they can find inside of China, or they can’t run effectively on it.

So, the Chinese are spending way more money than they should on building super duper expensive coal plants that can’t effectively run on the kind of coal that they can get. And they have a coal embargo against Australia, so they can’t import the stuff that they could actually burn effectively.

Meanwhile, solar panels have continued to get progressively less expensive, so that even in China, it is now cheaper to run solar panels than it is to burn coal.

The more uranium is used, the more it will increase in price, allocating more resources to exploring for new sources.

Increased uranium prices will not significantly affect energy cost, as fuel price is very small fraction of nuclear plant operation.

These days there are ways of getting uranium from sea water [1], basically making the supply practically limitless. This way is currently un-economical, but as current reserves are depleting, it will become viable option as well. (Along with researching for more reserves)

So yes, it was totally possible to decarbonise electricity production long ago.

[1] https://www.forbes.com/sites/jamesconca/2016/07/01/uranium-s...

It's wrong.

Breeder reactors can make fuel during use.

We only need enough fuel for one reactor.

> 75 years if we were running the entire planet on nuclear

That seems like plenty of time to

a) build renewables

b) figure out fusion

c) discover/make accessible more uranium just like we did with oil

d) Ramp up population to 20B people.

I believe Russia runs the only 2 breeder reactors known to be operational? So if they can get away with it, seems like major nuclear powers could agree to produce fissile material for energy purposes, keeping public record of how much is made and selling some limited quantity to poor countries for running small plants. Require public audits by an agreed upon body created for such a purpose and representing equally each major nuclear power. There can be solutions made.

It's a fair point. The US or Russia having more bomb-grade fissile material isn't such a shift in geopolitical reality.

There are 4 billion tons of uranium dissolved in the oceans [1]. That's about 80000 times the worldwide annual production.

[1] https://cen.acs.org/materials/Fishing-uranium-ocean-spider-s...

It's hard to believe that someone from the nuclear industry doesn't know about breeder reactors.

Nuclear fuel can increase during use. Running out isn't required, the way it is with consumable fuel

Exactly, it's a man-made, not a technical issue - breeder reactors are the solution.

It's not a technical problem (solution is well known), it's a policy problem.

Reply on news.ycombinator.com