Ultra Safe Nuclear (opens in new tab)

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. These can be more like 10s of years half-life. The counterpoint is that they become mostly non-radioactive in 100s of years, not 100s of millenia.

The actual environmental risks from long-half-life radioactive substances are pretty minimal as far as I can see.

The US makes this problem a lot worse than it needs to be by declining to reprocess nuclear fuel (I believe on proliferation concerns). Reprocessing is done in Europe, China, and Russia. You can separate the uranium & plutonium in spent fuel rods from the shorter-lived and much more nasty fission products, reuse the uranium, do something safe with the potentially weapons-grade plutonium, and then handle / store the separated fission products in a shorter-term facility.

The design goals of Yucca Mountain were assuming that you need to keep nuclear fuel safe for 100k years; that's an intensely challenging design constraint. If we just need to keep something safe for 100s of years it becomes much more tractable.

See https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/r... for some further reading.

The main problem with "nuclear waste" is that it is not waste at all.

If it is sufficiently concentrated in Pu238, then people might want to steal it to make bombs with.

Current LWR(s) use about 1% of the energy in the fuel.

Burying the waste in Yucca Mountain is like buying a gallon of gas, filling your car with a thimble, then carefully trying to store the rest of the gas so it doesn't ever get burned up.

The one reason we were going ahead with Yucca Mountain was a matter of "cutting off our nose to spite our face." That is, if we recycled nuclear fuel, somebody might use the recycling plant to make materials for nuclear weapons. If it wasn't for that policy of kneecapping nobody would have once suggested that we bury perfectly usable nuclear fuel.

People are slowly waking up to notion that burning carbon is slow motion suicide, so maybe policies will change.

Yeah, exactly. Even though it is costly to deal with, per kilogram, there is very little of it when compared to amount of energy produced. An atomic plant might use couple dozen tonnes of fuel which is peanuts compared to the amount of waste from coal power plant.

There are no technical problems with storage that we can't solve. The biggest problem is that nobody wants it around.

1. How long does it need to be kept safe?

2. How to find a storage facility that can keep it safe that long?

3. How to ensure that a facility does not contamine other stuff in X years?

4. if it is recycable why does nobody do it?

5. if it is so easy to store it safe, why does not country have a TRUE final depot?

yeah coal is bad, but why compare it to coal in the first place when we want to reduce such things anyway?!

I wouldnt necessarily agree. It needs to be stored for a time that is longer than any single civilization has survived. Its pretty arrogant to assume we will still be around for that amount of time.

This source pretty heavily influenced my change of opinion on nuclears efficacy

https://www.pbs.org/video/independent-lens-containment/

> Because it's not a problem.

Have you seen John Oliver's piece about that and can you point out the flaws?

> This number may sound like a lot, but it’s actually quite small. In fact, the U.S. has produced roughly 83,000 metrics tons of used fuel since the 1950s—and all of it could fit on a single football field at a depth of less than 10 yards.

A football field of forever death is not a comforting mental image.

In some places they use coal ash on the road for traction during snowy conditions >.<

Reading the Bloomberg article, it doesn't seem like the blades are a big problem.

> “Wind turbine blades at the end of their operational life are landfill-safe, unlike the waste from some other energy sources, and represent a small fraction of overall U.S. municipal solid waste,” according to an emailed statement from the group. It pointed to an Electric Power Research Institute study that estimates all blade waste through 2050 would equal roughly .015% of all the municipal solid waste going to landfills in 2015 alone.

- wind turbines have a 20 years lifespan, after which the blades are buried and forgotten, and will stay there forever

Nuclear power plants have a lifespan of about 50 years, after which the reactor and other parts will be radioactive. This waste must be buried, will be forgotten and will remain there forever.

I'll alleviate your concerns: it is not due to a big nuclear conspiracy aiming at making Big Nuclear fill its pockets, but by people who look at what physics dictates and notice that with our energy consumption things just don't add up. So you will see an increasing amount of (1) posts about nuclear, and (2) posts about de-growth or accepting to shrink economies through less consumption and production, not because there's a malevolent lobby but because people are becoming increasingly alarmed at the fantastically huge wave of problems already present due to climate change, and are acknowledging that the biggest mid-term effect is CO2 emissions (short term is water vapour and methane for what it's worth).

Side note: if you pick a conspiracy to get rich or defend "big money" interests or get swindled by, you're way better off continuing to side with oil and coal and denying that climate change is a thing - since nuclear takes gigantic initial investments and is not stock-market friendly but much more about countries' political will (and I got downvoted on previous discussions where I brought that up).

> have been wondering whether much of the evident pro-nuclear lobbying recently (it seems apparent on many threads here related to energy generation)

I think you are misunderstanding the selection bias. We're on HN, the selection bias here is that people tend to be more tech savvy and more informed. We have nuclear scientists here. You typically see acidburnNSA commenting in all these posts. I myself did radiation shielding research for NASA at a previous job. There's an old saying in the nuclear industry "Those that know the most, fear the least." I do not think it is "big nuclear" but rather that we're on a tech savvy forum. Take this to Reddit. You'll find more generalized forums are pretty anti-nuclear and more scientific forums are pro nuclear[0]. It really seems to come down to more where the conversation is taking place. I've met and worked with many climate scientists. I haven't met one that is anti-nuclear (I've met a few that think we don't need it if things keep progressing). If you press them on the subject most will just say they gave up because there is no support.

[0] I'll add that there's a lot of armchair talk and just ignore people that scream that Thorium is the answer. Easy way to pick out an armchair scientist. (Yes, I get frustrated with the armchair scientists that are even in my camp. Really moreso)

I'm a little disappointed that the Levelized cost of energy link does not include, you know, the levelized cost of various energy sources.

Also, it doesn't include the number of hours needed to find and debate a place where you can actually put down renewables.

Places using the most power (those most densely populated, like the Netherlands where I come from) have enough space for nuclear reactors to keep the country running (if base load was all we needed; it's just for comparison). However, if we need to do it all renewable, we're going to be hard-pressed and perhaps dependent on other countries. It's always someone's back yard or a nature reserve and people are almost always going to protest it. Germany has certainly more space so it's not as if we need to bring it all the way up from Spain or even Africa, but is by no means as sparsely populated as the USA (232/km² in Germany vs 34/km² in the USA). The USA also gets way more sun than most of western Europe. I'm not saying "you have it all easy" but... you're definitely in an easier position to make it work.

> the levelized cost of energy[1] for renewables like solar and wind power is substantially cheaper than nuclear power nowadays.

The reason for this is that they're backstopped by fossil fuels. You install solar, it generates power when the sun shines and you burn coal or natural gas when it's cloudy or nighttime. The energy they produce is thereby cheaper, but can only satisfy so much of the total demand before requiring energy storage, which dramatically increases the cost. Satisfying the remaining demand with nuclear is better than satisfying it with fossil fuels.

>it seems apparent on many threads here related to energy generation

It might be due to informed people reaching the same conclusion.

Do you have a source for blades often being made of toxic material? The Bloomberg article a poster linked above makes it seem like it's completely safe to store the blades in landfill: https://www.bloomberg.com/news/features/2020-02-05/wind-turb...

Well, you skip all the same nasty metals needed for the reactor vessels and support equipment too, so it's an even trade?

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.

Mining and enriching nuclear fuel is, what, benign?

Nuclear waste is not a problem, but not because it can be recycled. Reprocessing is an economic loser compared to just mining fresh uranium. The separated plutonium has negative value, and in thermal reactors much of it can't be destroyed before going into final disposal.

Yup, thorium-based nuclear power does not generate much nuclear waste at all, for example, and nuclear waste can be recycled, called "nuclear recycling"[1].

Nuclear waste is NOT an issue.

[1] https://whatisnuclear.com/recycling.html

If we plug in Brazil (2011 weather data, 2030 cost model) into

https://model.energy/

you get very good prices in a 100% renewable system. Mostly solar, with hydrogen backup (although this doesn't take into account Brazil's hydro resources which could make things even cheaper.)

There was a comment here about cleanup costs of nuclear vs. solar, that was deleted while I was typing my response to that. I'm just gonna copy in my response here, because I think it's an interesting topic:

Are we really sure solar panels are much easier to dismantle on a euro-per-kWh basis though? That is, if you divide the total cost of dismantling and recycling a solar power plant, divided by the total amount of energy produced over the lifetime, does solar power do much better than nuclear?

Nuclear power in Germany (17 powerplants) has produced well over 5 million gigawatthours over the lifetime so far. It's hard to put good numbers on the cleanup costs, but somewhere in the ballpark of 50 billion euros is probably correct. (Keep in mind that some cost is the government paying the powerplant owners compensation because they are forcing them to shut down long before end-of-life).

So that gives you around 0.01 euros per kWh. A solar panel with 20% efficiency placed close to the equator produces 500 kWh/m2/yr. Over 30 years of lifetime that would produce 15 000 kWh/m2.

Are you sure you would spend significantly less than 150 euros per square meter of panel to dismantle, transport and recycle the solar panels?

Fission is ultra-complicated and dangerous with Uranium.

I can buy a solar panel for $100 and have it generating electricity in my backyard at a click of a button

Why would I _not_ do that?

Installing a solar panel can be done today, for a $100. Tomorrow it will be $50, and it’ll keep going down until the market dictates the price.

Nuclear takes years to build and generate output, and the price is going up. It would be foolish to build a nuclear plant today unless you have a specific need for it (small location, little sunlight/wind).

Personally I think that in 20-40 years time most people will get the bulk of their energy from local solar panels, with the grid, backed by a mix of renewables and existing non-renewable sources filling in all the gaps.

what about cultural changes ? serious question. less living at night, less energy consumption, making sun randomness a bit less of an issue. Just asking.

Not really. It's rather expensive (billions of dollars) to setup a nuclear plant in the first place, even before a single fuel rod shows up. Meanwhile solar is so cheap and easy that you can install panels on your roof yourself.

30 workers isn't a lot for a power plant. According to this article[0] (ignore the coal stuff) a decent gas turbine plant takes ~25 workers to keep it running, and that's for a system whose energy source can just be piped in rather than having to be constantly babysat so it doesn't irradiate the tri-county area. That's kinda the flaw of a steam turbine based system; it doesn't matter if the heat comes from coal, uranium, concentrated solar, whatever, you still need people around to make sure the system with superheated steam and a big heavy turbine spinning really, really fast doesn't go wrong.

[0]https://www.powermag.com/supporting-coal-power-plant-workers...

Do you get out of your car to wipe your windscreen when its raining? This cleaning problem seems like something that would be super easy to automate, I dunno why they would higher 30 people to do this when you could higher one engineer.

Not that I oppose to nuclear in principle, I only wanted to point that for heavy industry there are clean alternatives in development using mirrors.

https://heliogen.com/ https://news.ycombinator.com/item?id=21955247

50m2 Solar on the roof top of every household would power An average western country. That is not a lot. And that is is an upper band as we have wind power, biomass, hydro power geothermal and many other sources of clean energy.

Offshore wind is getting really cheap and offers vast amount of unused space.

This is a nonsense argument. How does the energy density of renewables prevent them from providing all the energy we need? Show us the quantitative argument (spoiler: you will not be able to do so.)

We do have a good way to store energy. It's called batteries, they are already cost effective in several use cases, and their cost is going down about 5% per year.

A Tesla model 3 can power a regular house for around 4 days. It comes with bidirectional charging and so does plenty of other modern EVs. Tesla is soon coming with their million miles battery which makes this even more feasible.

You charge the car to the max while the sun shines and drain it when the sun does not shine.

The distributed nature of renewables is actually a huge advantage. It means the renewable system is extremely fault tolerant. Not only does that help in operation, but it means installation is much more forgiving of low quality work (so you can use cheap labor that's easy to train). Screw up 1% of the modules in a PV field and output is down 1%. Screw up 1% of the welds in a nuclear power plant and you have a world of pain.

All indications are that much was learned by industry and the NRC after TMI: "...The NRC said the TMI accident also led to increased identification, analysis and publication of plant performance information, and recognising human performance as “a critical component of plant safety”. Key indicators of plant safety performance in the US have improved dramatically. Those indicators show:

• The average number of significant reactor events over the past 20 years has dropped to nearly zero.

• Today there are far fewer, much less frequent and lower risk events that could lead to a reactor-core damage.

• The average number of times safety systems have had to be activated is about one-tenth of what it was 22 years ago.

• Radiation exposure levels to plant workers have steadily decreased to about one-sixth of the 1985 exposure levels and are well below national limits.

• The average number of unplanned reactor shutdowns has decreased by nearly ten-fold. In 2007 there were about 52 shutdowns compared to about 530 shutdowns in 1985."

https://www.nucnet.org/news/three-mile-island-led-to-sweepin...

No one ever promised that there would never be a nuclear accident - that would be unrealistic for any power source. But historically nuclear power has been safer than all the alternatives that were available.

https://www.statista.com/statistics/494425/death-rate-worldw...

https://ourworldindata.org/safest-sources-of-energy

https://www.nextbigfuture.com/2011/03/deaths-per-twh-by-ener...

https://www.forbes.com/sites/jamesconca/2012/06/10/energys-d...

Unfortunately anything at all related to nuclear is covered by the media orders of magnitude more than other power sources so many people have an understandable perception that it is much more dangerous than other sources of power. 200 thousand people had to be evacuated in CA a couple of years ago because of a lack of maintenance on a hydroelectric dam could've let to catastrophic failure. We got lucky that time as the rains stopped just in time, but how much did the media cover that story? How much would they have covered it if 200 thousand were evacuated because of a nuclear power plant?

It is possible there will be some major advances in grid storage that will allow us to stop using natural gas to cover for the intermittent nature of wind and solar. But what if that doesn't pan out? The dangers we are facing in the coming decades are immense. Is your fear of nuclear power so great that if you had to choose, you would prefer the world to suffer through catastrophic climate change rather than use nuclear power?

If you are short on space for your solar panels put them on your roof, problem solved. There are cheaper better ways of storing electricity like water stores, and this is what they use not batteries, they have never used batteries thats just a Tesla thing.

Land usage is not as big problem as it seems. E.g. wind turbines must be spaced out far from each other but most of the land between them is perfectly usable for farming and animals.

As for solar. For an average western country 50m2 of solar panels on top of each household covers all electricity needs of a country.

Obviously this power is not delivered exactly when you want it but it is to give some perspective on the space required.

And you don’t need massive batteries. Many countries are building pumped hydro to store power.

You can use biomass, geothermal power. MMR and SMR reactors with molten salt thermal storage as a way of storing energy.

Thanks for bringing up these two points. I have heard people saying lets put solar plats in deserts. They don't realize the deserts also have an Ecosystem.

The cost of land for PV is a small fraction of the cost of the PV put on that land. Land is very cheap in most of the world.

And yet, the cost of a kWh from renewables is less than from nuclear, for all the supposed advantage of nuclear's energy density. This should tell you that energy density is not actually a good metric.

There is actually an apparent upper limit on energy usage once countries reach a certain level of development. See for example [1] and [2]. Total energy consumption in Western countries has been level or dropping for years as devices that use energy become more efficient.

[1] https://www.eia.gov/todayinenergy/detail.php?id=39092

[2] https://www.euractiv.com/section/energy/opinion/eu-at-risk-o...

This is mathematically impossible. The entire world could be powered with 200,000 square miles of solar panels.

Since 1990 we’ve lost ~2.5x that amount of land to deforestation, approximately zero of which was due to building solar.

We have a deforestation problem, but it has nothing to do with solar.

That is extremely unlikely. You need to cover single digit percentages of the world with solar panels (depending on latitude) to cover all our energy needs.

Is the point you're trying to make that nuclear and fossil fuels can both be dangerous during a natural disaster? I don't think anyone will dispute this.

> the areas that were evacuated are now safe to return.

is this true for Fukushima? As far as I understand, 8% of the "Difficult-to-Return zones" have been cleared up for access to people, but that is a far cry from "all cleared up, everybody goes back home".

[0] https://mainichi.jp/english/articles/20200916/p2a/00m/0na/01...

You are joking about "small numbers of deaths", right?, because this millennia is not over yet.

> First, point out that Chernobyl, 3 Mile Island, and Fukushima amount to extremely small numbers of deaths relative to the power these plants generated.

I keep seeing justifications like that and it makes me want to puke. First of all: The total number of victims is unknown and it is still rising. Even for Chernobyl.

Second: It costs tens of billions of dollars to clean up these messes. Paid for by the cow you can milk forever: tax payers.

In short, if the goal is decarbonization wind and solar are the only game in town. Add medium and long-term storage to the mix and there's nothing stopping us from a truly green future other than politics.

You haven't answered the question though. How do you get the public on board?

Apples to oranges. Reactor designs are completely different. They are basically set it and forget it designs that then require extremely costly refueling and refurbishment.

Edit: I was wrong, the Ultra Safe Nuclear plan is somewhat similar. My comparison was with typical power grid reactor designs, not disposable reactors like what's being proposed.

Is there a particular reason why solar and wind aren't competitive in Ukraine, while in general it seems like those technologies are some of the cheapest sources of energy available today?

> Actually, I can't understand why all those who are predicting doomsday scenarios because of climate change aren't storming the streets with big pro-nuclear energy signs.

Agreed. Without being a primitivist, I don't think you can be both pro-environment and anti-nuclear at this point. Solar and wind just don't have the output to keep up with industry. If we're fine living in mud huts and it taking 6 months to produce a laptop, then fine (and honestly that might be the place we end up in 100 years). But as it is, solar and wind cannot sustain our current economy.

That's deaths per joule so far. How would nuclear compete if far more renewables were installed, producing far more joules?

How about clean-up costs? Estimates for Fukushima vary from $76bn to $660bn depending who you ask.

https://www.scientificamerican.com/article/clearing-the-radi...

How about general carelessness?

https://www.scientificamerican.com/article/nuclear-weapons-s...

This is not unusual for the nuke industry, both civil and military.

Which is the problem. This is primarily a managerial issue, not a technological one. And the quality of executive and managerial decision-making of all kinds across the entire industry is nowhere near the standard required for future confidence. Especially given increasing risks from extreme climate change events.

Except... we don't know what the deaths are. It will take tens of thousands, hundreds of thousands of years to know what the death toll is from nuclear power. Because humanity is stuck with the waste for hundreds of thousands of years.

We use only tiny amount of the energy available, then have waste to deal with through the ages.

I'm in favor of nuclear, but wow are we ever terrible at innovating & trying to make a respectful, compelling go at it. Kerry shutting down the Integral Fast Reactor keeps coming back to haunt me as one of those strong indicators that America doesn't want to put itself up to the challenge of doing nuclear responsibly.

Sources on the deaths per joule claim:

https://www.nextbigfuture.com/2011/03/deaths-per-twh-by-ener...

https://energycentral.com/c/ec/deaths-nuclear-energy-compare...

Yeah perhaps but the tail risks are much higher.

>rebrand it. Drop the word "nuclear".

I laughed at the thought of A/B testing new names of fundamental forces across different demographics.

> I don't think its a zero sum game, nuclear doesn't preclude solar or wind.

That's what I'd like to think, but it doesn't seem to be a good match.

Nuclear plants want constant power output, they are ideal for base load. Solar and wind production vary during the day, and they don't always meet demand. That problem is called the "duck curve": too much is produced during the day and too little just after sunset. That's the reason why the best plants to complement solar and wind are those that can vary their output on demand. And unfortunately, that's typically coal (see Germany). Hydro would be ideal but its capacity depends is limited by the terrain.

> The fact that ALL energy in our solar system comes from the sun is irrelevant

Except human-made nuclear fission energy on Earth, somewhat ironically, given the thread.

People aren't afraid of solar panels, and the tailwind probably refers to the fact that they're getting cheaper at an extremely rapid pace.

How many people with increased cancer rates from solar? Stop quoting deaths from nuclear accidents - the harm from nuclear incidents goes far beyond killing people outright.

Picking a nit here. You wrote:

> Nuclear is outrageously expensive, though. And new reactor designs don't seem to be making much progress on that.

Nuclear plants are expensive the way GE and Bechtel build them not inherently so. At some point I got to look at the Diablo Canyon cost-to-build breakdown and about 2/3ds of the cost were litigation, licensing, and specialized site and construction prep. Finding people who could do the kinds of welds they needed, build structures in the right way, inspect, inspect, inspect, and litigate dozens of lawsuits asserting on form of harm or another. It was pretty amazing.

This particular company can build the reactor in their factory. All their specialists are in one place, you can have permanent inspection equipment with costs amortized over all the reactors you build, and the safety systems this reactor design purports to have means no additional site prep (no backup generators, no double containment vessels, no borosilicon sandpits under the reactor to slag into glass while "catching" a meltdown.

If I were to guess, while the pitch is all about safety, this design screams that it is all about cost. When you factor in that the design in modular, so making a 100MW power station with 20 of these gets advantages of scale that multiplies the cost advantage.

When I read this I see those cost savings and recognize this could be both cheaper than renewables and way more reliable. A solid base load solution to kill the last of the coal plants.

Two questions: (1) Night time. (2) Quiet time.

Of course there are batteries! But factoring them in seems to increase the cost significantly. Power lines and cross-continent smart grids are fine, too — but also not free to build and operate.

So a self-contained unit that does not depend on weather, does not need refueling, and includes its own energy accumulator has some appeal.

>it costs 3-10x what the equivalent generating capacity in renewables would cost

Except renewables can't actually replace fossil fuels. They need baseload provided by fossil fuels to be viable. They are also defuse energy sources, and so require huge surface area and lots of materials for collectors - not great for a growing world, both in population and per capita energy needs. Oh, they are variable across days, seasons and inter-year periods, but there is no battery technology coming that is able to store even enough power to a moderately sized city for a few minutes, much less the weeks it would need.

>And when we get to that last 5-10%

Try 50%.

The growth numbers currently show that for every extra watt of renewable energy consumed globally, 10 more watts of fossil fuels get consumed. (https://ourworldindata.org/energy#energy-consumption-by-sour...)

Looking at the multiple data sources at https://en.wikipedia.org/wiki/Cost_of_electricity_by_source, there is several patterns that should be fairly clear. Gas and oil is very cheap to build, and the market price they can get out per generated MWh is higher.

> Look, I think nuclear is fine. But as a numerate and earnest environmentalist, I don't see where the case for it lies

Lets put this is in numerical estimated numbers.

An investor builds a wind farm. On average they produce a MWh that costed $35. For the period which the energy was produced they managed to sell it for $85 netting them a profit of $50.

An other investor builds a natural gas power plant. On average they produce a MWh that costed $45. Since they can choose when to produce it they managed to get an average price of $150, netting them a profit of $105.

As a balance sheet, $35 is a cheaper price than $45 when producing 1 MWh. $50 is however much less than $105, making the more expensive energy source the more profitable choice of investment.

Cost is just half the picture in any commercial venture. The daily energy price for 1 MWh varies heavily based on demand and supply. $50 per MWh one day could be $500 a few days later when supply is low and demands is high.

I would also describe myself as numerate and earnest environmentalist, and my view is similar to your but with a clear distinction. Right now we must stop burning fossil fuels. If it cost $45 to produce and they can earn $150, investors who only care about money will continue to invest in fossil fuels. That must stop. The climate will have won a partial victory when the investment into fossil fueled power plants are a proven poor investment, and then we can move on to the transport sector.

I don't think they're necessarily chasing grid power at first anyway. They seem positioned to tackle mass market electricity last, after addressing smaller higher price markets.

> the equivalent generating capacity in renewables would cost

But most of the time, the “cost” of renewable is undefined, because you simply can't use it: you need the grid to compensate for the intermittent generation. No battery won't be enough unless you are in a really specific situation:

- hydroelectric source available, in which case, it's a no-brainer, but most of those sites are already exploited (hydroelectric power was historically the first to come).

- if tpu want to go for solar power, you need tropical or subtropical area, where you have the same amount of sun during the whole year. Otherwise you either need to have batteries able to sustain the whole winter, or dimension your system for winter (which dramatically increases the cost and you end up with a lot of unused power during summertimes).

- for wind power, you need a regularly windy area (the top of a hill, the middle of the sea) and batteries because the world best wind power sites still don't produce every days (storms means shutdown for instance).

If you don't have the perfect spot for one of those, the batteries aren't even a solution[1], because you'd need something like two to four weeks of power in terms of storage…

Or, you could go for a mix between fossil fuel and renewable, which is why the oil and gas industry is making a big push towards renewables …

Think of smaller nuclear reactors as an option for places where renewables might not make sense, like in mining. Building power generation that costs 10x some renewable source will never make sense. However, building small scale nuclear as replacement for onsite diesel generators could make a whole lot of sense. Illinois Energy Prof has a good video on this => https://youtu.be/7gtog_gOaGQ

> But as a numerate and earnest environmentalist, I don't see where the case for it lies.

There's two main benefits to nuclear:

1) The big case is the lack of good power storage. While areas like the South West US have plenty of sunshine to go around, most other places don't have this luxury. Therefore you need substantially more storage. I'll give you an example, I've been sitting in Oregon for the past week and sun levels have been pretty abysmal, the past week. Dust and ash are covering panels, making things worse, and this is the sunniest time of the year. There's plenty of times I don't see the sun for a few days straight. Same with wind. Because of this we need to mix up our power sources a bit. I mean you also don't want to depend on only two power sources. I think most of us in the nuclear community agree on: wind + solar + hydro + nuclear as the model. Without good enough batteries nuclear is a great option for baseloads. Remember that you need enough battery storage for rare events where there isn't much sun and wind. Current solutions aren't quite there yet without massive footprints, CO2eq costs, and a high price tag. The unfortunate fact is that wind and solar can't stand up by themselves. They need support. People talk about how you can do it with batteries, water storage, whatever, but until it is implemented I'm not holding my breath.

2) Nuclear has a small physical footprint. This means less disruption of local wildlife, homes, etc. This is a big environmental factor to me.

As to what these people are doing, there's a few factors they are banking on (bets). It'll be interesting to see how that pans out and if their bets can pay off.

- With small modular designs they can get the benefits from economies of scale. This hasn't ever really been a thing for nuclear in the past. This has been a big driver for the huge costs.

- Small reactors should be cheaper to insure (this still needs to be resolved from what I'm aware of and has historically made small reactors unattractive).

- Small and modular enables the ability to better fit the local environment and meet the specific needs. Southern California? Probably don't need any. Alaska? Few would be nice. The idea behind these is that you don't have to transmit energy far (lower loss due to transmission), can add independence from the grid (to corporations or universities), and you don't need to put them in areas that can better rely on wind and solar, i.e. better scaling than conventional nuclear plants.

Of course, this is still a bet and has been one people have been talking about for well over a decade, but why dismiss it before they place their chips? If the bets pay off we should welcome them with open arms. If they don't pay off, well we're on a forum hosted by a startup company where we all know most startups fail. Glad someone at least tried. We're not talking about enough investment money that it would sway the scales and it is good to spread out your bets.

So, why did so many countries/companies originally build nuclear reactors, if the economics inherently don’t make sense? Has something changed?

And renewables are cheap because peaker plants exist, which allows the price of storage to be externalized to the peaker plants.

If it can be combined with desalination, and profitably create medical isotopes, that could help balance the books. But yea, you are right. And solar keeps getting cheaper.

Well, I am still hoping for ITER.

Not to mention the waste which needs an armed guard almost forever, making the total cost of the energy almost infinite.

I’m okay with costs being 3-10x for something with zero emissions. And the more we build the cheaper it gets. We have to invest in the future technology. Solar is a good 20th century technology but it is poisonous and degrades over time. Wind is useless.

I highly recommend HBO's Chernobyl. Explains a lot this stuff. Basically, as a nuclear reactor operates, it is turning the Uranium into lots of other stuff. One component of this other stuff is Xenon-135, which absorbs neutrons and basically gets in the way of nuclear reactions. This is not an issue if you keep the reactor on because there are enough neutrons to keep things going and overcome the Xenon absorption. But if you turn the reactor off, you now have no neutrons from the fission reactions and lots of neutron absorbers. There is so much absorption that it's impossible to start up the reactor for a couple of days. That's why nuclear reactors operate at constant power and only turn off to refuel. This MMR also operates at constant power, which would also have benefits for cycling issues, and uses the molten salt loop to store heat and then use it when it's needed.

In a situation where you want to rapidly ramp a generator's output up or down, Xenon poisoning narrows the window of reactor control system authority. This prevents the reactor from achieving full power on a reasonable time scale.

Xenon is both a fission product and a neutron absorber. So if your reactivity dips too low you won't have enough neutrons buzzing around to sustain the reaction and will have to wait for the xenon to decay before you are able to start up again.

"Inefficient" = 90%? I think you need to think more about what you've written there.

> 1% of commercial reactors Have failed catastrophically.

That seems a bit high to me. There have been a lot of commercial reactors.

> Seems like terrible track record.

Even if true, everything fails sometimes. Rooftop solar has a surprisingly high death rate from people falling off of roofs while installing it.

Ultimately it's a question how safe nuclear is relative to other power methods, probably in terms of deaths per terawatt hour. And even counting those catastrophic failures, it turns out it's actually extremely safe. (...which really underscores just how horribly dangerous some of the alternatives are...)

None of which means nuclear power is economic.

100% of fossil plants fail catastrophically; the catastrophe is just a bit slower.

Statista claims there are 440 nuclear power plants in operation today, and most of them probably have several reactors. So unless you're using some technical meaning of "commercial" that precludes things like Chinese SOE, I think the claim is just false.

No because now we have designs that cannot fail in the same way that 1% did.

Yes, that has been the common factor in most incidents. Chernobyl being the exception, they didn't manage even manage to get the control rods fully inserted before the shit hit the fan (poor reactor and control rod design).

Still, the British AGCRs were recently fitted with articulating control rods because if the reactor core was damaged they might not be able to insert them normally.

The Wikipedia page is a lot more detailed than I could hope to be, presumably you just turn off the power to the particle accelerator.

Existing safety measures rely on some degree of integrity in the reactor at the time they are triggered. If it gets too damaged before the control rods are inserted it may not be possible to insert them.

https://en.m.wikipedia.org/wiki/Subcritical_reactor#:~:text=....

But they don’t lose the liquid coolant - which seems like a pretty reasonable scenario.

The video on their homepage explains their approach to waste disposal. About 60 seconds into the video.

Chernobyl caused the near permanent evacuation of a nearby city, and nearly poisoned the water supply for millions. Not a good example if you’re trying to argue a release of fission products is no big deal.

I would like to understand exactly if/how this reactor design gets around the risks inherent to explosions of radioactive fuel. If it’s not a problem then why does the marketing take pains to say it will never leave its capsule?

also they used a strange control system. No control rods. Instead they moved the whole core up and down to change reactivity. wtf?