Nuclear startup Oklo gets thumbs-down from regulators


I don't think it's a bad reactor but I looked at the application and it wasn't a good application. (The NRC says the same)

There was a large amount of hand-wringing about the risk of avalanches and other natural disasters that were extremely low probability.

They were skimpy on interesting details about the reactor such as "What do you do if the sodium coolant catches on fire?" (e.g. sodium burns in water, sodium burns in air, sodium burns in carbon dioxide) There are good answers to that in the U.S. and Russian experience. They don't draw on that experience to show they can solve it.

If they fix the application and submit it again it could get approved.


I think it is probably a bad reactor and a questionable company.

1. The company is totally opaque on even basic design details. This is not ghost mode. It's likely hiding incompetence and lack of design work / maturity.

2. It's a fast reactor so lots of high energy neutrons that will cause faster material degradation, higher maintenance cost, more downtime - the economics for fast reactors have never worked (not even in Russia or China), and this is probably why fusion reactors will never be economical (32x greater neutronicity).

3. It has terrible fuel utilization: 1% burn-up of fuel, with 100 metric tons uranium / GWe-year compared to 5-10% in other normal and advanced reactors.

4. The founders lie to congress claiming their reactor “can consume the used fuel from today’s reactors” when each reactor is actually going to require 3 tons of pretty pristine HALEU...

5. The founders peddle some serious BS (bitcoin mining, TED talks ... etc) not unlike the other great MIT nuclear startup Transatomic.

6. NRC really went out of their way to publicly reject this with press release and all. This was not done lightly to a company often featured in the WSJ and Popular Mechanics.

7. I'm disturbed by the way they talk about their reactor as a "community meeting place" with their modern glass A-frame without any power generating equipment. Is there going to be a daycare center or country club in there? Where the hell are the cooling towers? I'm all for nuclear power, but we shouldn't be down playing the seriousness of nuclear power systems.


Look to FFTF for a completely successful fast reactor run in the U.S. that was unfortunately shut down for political reasons that, retrospectively, look like a terrible mistake.

One of the most interesting features of the FFTF was a sodium-to-air heat exchanger which is a key to fast reactors having superior economics.

That is, no nuclear reactor which uses a steam turbine is going to be economically competitive with fossil fuel fired gas turbine generators. Between the absolutely huge and massive steam turbine and absolutely huge and massive heat exchangers (look at how big the steam generators are in the PWR or the huge tube-in-shell heat exchanger used at Dounreay)

A closed cycle gas turbine will fit in the employee break room of the turbine house of a conventional LWR. It requires some kind of reactor that runs at a higher temperature than the LWR. I like fast reactors and molten salts but have a hard time being enthusiastic about HTGR and friends.

So much of the literature still looks like a stopped clock. People still compare nuclear to coal although coal has been economic for a long time for the same reason as the LWR... The cost of that huge steam turbine.

Problems with fast reactors I worry about are the fear of proliferation (not proliferation) constricting what you can use for fuel and (more so) the plutonium nanoparticle problem w/ MOX fabrication. Of course you don't need to use MOX or you'd think in 2022 you could use 100% remote handling and not have the problems that Karen Silkwood was worried about at the place where she worked.


I went looking for operating closed cycle gas turbine power plants- this seems like a research topic all on its own, no matter the heat source.

It's definitely true that simple cycle gas turbine plants are much cheaper than equivalent size steam plants. This right here sets the bar for any kind of thermal power plant.

See table ES3 for cost comparisons..


> One of the most interesting features of the FFTF was a sodium-to-air heat exchanger which is a key to fast reactors having superior economics. > That is, no nuclear reactor which uses a steam turbine is going to be economically competitive with fossil fuel fired gas turbine generators.

OK, but FFTF reactor has not generated electricity at all. How is “sodium to air heat exchanger” supposed to generate electricity, to make it more economical than steam turbines?

> That is, no nuclear reactor which uses a steam turbine is going to be economically competitive with fossil fuel fired gas turbine generators.

That’s highly likely to be true (at least until cheap gas runs out, which will happen at some point, though it will take many decades/centuries until then), but I thought we are aiming to get off fossil fuels, no? We should be willing to pay some premium for nuclear, because it does not emit GHG.


> the plutonium nanoparticle problem w/ MOX fabrication.

IIRC the Oklo design is using metal fuel, like EBRII or IFR? And the Russians are apparently working to switch from MOX to nitride fuels in their fast reactors.

Anyway, the French have been producing MOX fuel at industrial scale for decades, AFAIK without poisoning their workers. Maybe they are doing it smarter than the Americans in the 1970'ies.


Can you elaborate as to why you aren't excited about HTGRs?


> I'm disturbed by the way they talk about their reactor as a "community meeting place" with their modern glass A-frame without any power generating equipment

I'll submit that a nuclear startup that presents such a stylish Architectural Digest concept for its facilities, that by itself is enough for us to be extremely skeptical of the leadership team. Their head is in the wrong place.

You will counter-argue that it takes little effort for them to hire an artist-designer to create the rendering. Nonetheless: their head is in the wrong place. They're not reading the room. None of us (not the public and not the NRC) are looking for a new alpine lodge to grab an espresso. We basically just care that you don't blow up and you don't poison the land, water, and air around you.

If leadership spend any cycles to spend on hiring a stylish designer, then their priorities aren't straight.


It would seem that both could be possible, but you're the expert here. ;) We didn't have to spend much time or money on an actually nice looking design, and the a-frame has a lot of practicalities I'm happy to talk about more (modular construction, resilience against snow, useful angle for the solar panels, strength for the internal cranes). (and yes, the power generating equipment, offices, and other space, is inside)

I guess then again here I am as part of the leadership engaging in communicating with the HN community on a friday night and hopefully transparently answering questions. I guess I can't help myself! I do think the public needs to both learn about the realities of fission, and I don't think it has to be ugly.


Presumably they're trying to shift the image of a nuclear plant from "dangerous, not in my backyard" to something more friendly and appealing.


I am all for style, but they aren't sending the right message. There's a certain beauty in a cartridge reactor that is buried below grade and shows hardly anything.


> the economics for fast reactors have never worked (not even in Russia or China)

Russia currently has two sodium-cooled fast reactors that are producing power, the BN-600 and BN-800. They also have another sodium reactor under development, the BN-1200. BREST-OD-300, a lead-cooled fast reactor, is under construction as well.


But those don't have to be economical purely on power generation, right, because they also produce Pu-239? Presumably fast breeder reactors would be useful to the Russian state even if they didn't produce electricity at all...


> 2. It's a fast reactor so lots of high energy neutrons that will cause faster material degradation, higher maintenance cost, more downtime - the economics for fast reactors have never worked (not even in Russia or China), and this is probably why fusion reactors will never be economical (32x greater neutronicity).

Commonwealth Fusion Systems's ARC has an interesting approach to handling this -- using a liquid blanket which can be circulated. Of course, ARC isn't built yet! But if that approach is workable, perhaps it can be applied more generally?


I believe it has to be replaced every 4 years of operation as intermediate level radioactive waste.


Hey Gloriana, I'm sure PR experts would say I'm probably not making a good decision responding here, and I haven't even had anything to drink, but I'll take a stab at sharing a bit on each of your points. I hope this response will be taken in the good faith in which it is given.

1) There's certainly many hundreds of pages/slides in the fully public docket on the NRC website, but the easiest source for the most information in one place is our application itself: I don't expect anyone to want to read that entire thing either, but it's there. The only main things that are withheld are generally either: export controlled (defined by the Department of Energy, and we take it seriously) which includes detailed core maps, or security-related information (defined by the NRC). But the rest of it is all there. If there's something you want to know that isn't there, I'm happy to respond.

2) We are building our designs off the 30 years of experience and data with EBR-II and other fast reactors ( EBR-II was ended prematurely for political reasons and had plenty of life left. The EBR-II showed how electricity could be put on the grid with higher uptimes than even the commercial fleet at the time. Unfortunately, I can't give details, but let's just say other major developers of historical fast reactors didn't release their economics because they didn't want it to cannibalize their other plants. But you don't need to believe that either. Our business model is to provide power via PPA so if the economics don't work for the customer we simply won't have a deal. Our FOAK plants are economic already in remote or higher cost areas, but the real key to our economics is when we are able to recycle existing waste, a fact unique to fast reactors.

3) 1% was really to be conservative for the FOAK, to try to make the licensing of the FOAK simpler within the datasets we had. I assume you know a number of SFRs have worked toward establishing datasets for up to and beyond 15% burnup. I really don't know where the number of 100 MT of uranium comes from. We would have <5MT total of fuel for 20 years, with <1T of that being uranium. 1.5MWex24hrx350days/yrx20 years is something like 250 GWe?

4) Oof. Yes, fast reactors can consume the fuel from today's reactors, and even though that supply chain isn't established, the FOAK is using waste fuel from EBR-II. I can assure you it is not pristine. No one else wants it. :) But we are working together with the DOE on a project with Argonne National Lab to begin work on the recycling from today's reactors (

5) Hm. well, I want to be positive here: I'd argue there's a difference between our first customer announcement being Compass and a TEDx with my alma mater, and moving forward for years with something that fellow students and professors said had fundamental issues since grad school, which a professor finally leaked to the press out of frustration (and yes, we might have been fellow students). It's funny, I always said we should never do a TED too because they seem so smarmy, but a friend at my undergrad and the students there were organizing a TEDx and honestly it was cute and was just a fun opportunity to go back there for various reasons. We've been working with other more traditional customers in ways that we can't announce yet. But, we are working with other customers you'll likely approve of more. Remote communities as well as big companies just truly do need reliable power and they do want it to be emission-free.

6. They did seem to go out of their way didn't they. More will come on this once we are able to put out our own account too after 30 days, just because we should have the opportunity to set the record as well. But, to put myself in their shoes, they are trying to defend against an appeal or legal action. Neither of which we really have interest in, we just want to try again, move forward.

7. I responded to this with Paul. TL;DR: I don't think an attractive and functional building with all required security and operational characteristics means we are "down playing the seriousness." If you've been out to these truly poor, remote communities in the Arctic circle as I have, you'll see why they care about having heated, lighted, indoor areas in the long winters. And when the analysis shows the safety and security required, why wouldn't we offer that to them?

Well, there you go. Feel free to pick it apart but hopefully it added some context to the press releases and pretty pictures and whatnot.


Thanks for the response.

I had previously gone though the Oklo COLA, which is indeed hundreds of pages. But quantity is not always quality. I have seen the same types of submissions from other reactor proponents, and they are far more detailed, comprehensive, and informative and they are mostly at earlier stages of NRC engagement in pre-application discussions. As an example, I can't find a basic dimensioned or labeled reactor drawing or system diagram in Oklo's COLA. As far as the COLA illustrates, the Aurora design consists of an A-Frame drawing and a cylindrical vessel in a dugout. The safety analysis provided are generally simplified, rarely showing uncertainties or limitations of the analysis. See the NuScale or GE-Hitachi designs in pre-application or even the Transformational Challenge Reactor (TCR) as an example of a well documented research thrust that has not even begun the regulatory process if it ever will:

As far as spent fuel goes, the EBR II fuel that Oklo plans to use took decades to reprocess at a cost much greater than 0, which Oklo is not paying for. EBR II is not a civilian power generating reactor like all LWRs and BWRs currently in operation. Perhaps one day, reprocessing spent fuel will be cost effective. But today, it is a totally unnecessary activity as there's plenty of uranium and spent fuel storage is not an issue. I think telling congress that Aurora will consume spent fuel from today's reactors is false and disingenuous, both because it is extremely expensive to do so and because it is not particularly useful.

Aurora is ostensibly a tiny fast reactor, though I have to guess at this as there are no dimensioned figures in the COLA. Neutron leakage is going to be big and burnup low. This might be why Aurora is limited to 1% burnup. Maybe Oklo plans to make much larger reactors in the future, which have very different safety characteristics but can achieve higher burnup. It's curious that of the 70+ reactors in development, there are no fast spectrum and tiny reactors except for Oklo. There are fast reactors like TerraPower Natrium but they 200x larger than Aurora.

The calculation for tons / GWe-yr is as below assuming a 33% efficient power cycle (reasonable given the low temperatures of the heat pipes, but maybe the sCO2 is really good). GWe-yr is a unit of energy.

1.5 MWe * 20 yr means you are producing 4.5 MWth for 20 years, and must have fissioned 35 kg of Uranium (you get 200 MeV per U fission which is 2.6 MWyr / kg U). If 1% burnup is assumed, as indicated, Aurora is using 3500 kg or 3.5 tons of HALEU. I think this would change a bit depending on the spectrum.

3 tons HALEU / (1.5 MWe * 20 yr) * (1000 MW / 1 GW) = 100 ton HALUE / GWe-yr






In Fusion reactors the neutrons are used to breed Tritium from the Lithium so they're not hitting the structure and degrading it.


Not quite. 80% of the energy in D-T fusion reactions are released as neutron energy. I sure hope most of that will be used for generating electrical power rather than breeding tritium... :) The dpa rates and helium embrittlement are way higher for fusion and fast fission reactors than for thermal fission reactors. See Figure 3 and 5 of


So, we have half a meter of lithium just sitting there, not contained in any structure?


This is a great assessment of the response by the NRC. The operating phrase to focus on is "without prejudice," which in this context means "just fix the problems and try again."

We applied for a direct to phase 2 SBIR in 2020 and were thoroughly denied, mostly due to fixable errors in our application that we made because we put it together ourselves and had never applied for a grant before. After involving some consultants and the relevant institutions, we got a much lower impact score and are likely to receive the grant soon.

Moral of the story: you can't fake regulatory experience, and regulatory applications require specialist knowledge to put together correctly.

I wish them all the best in their resubmission!


> you can't fake regulatory experience

While that seems true, but reading previous applications doesn't help?

> and regulatory applications require specialist knowledge to put together correctly.

Again, seems trivially true, but (again) how come you can't copy-paste a previously accepted application? (I mean, if you find a very similar site, same risks, hazards, geology, weather patters, distance from population centers, blablabla, same technology, same trade offs... shouldn't it be okay? [assuming the regulations haven't changed])


Nobody has gotten an application approved for a new reactor (e.g. not an LWR) yet.

It's not that the NRC is unfair but it is like private spaceflight. For years there was talk at best. Designs like

have been up in the air for decades but nobody was serious about getting approval and building them. Oklo ought to be proud to be the first to get shot down, pick themselves up again, and submit a better proposal.


Most regulatory consultants give hyperfocused advice specific to your application, and cost in the ~$10k order of magnitude, sometimes pushing the ~$100k. Given the capital investments in applications, you'd be hard pressed to find successful, complete applications with enough details relevant to your proposal that you could simply plagiarize them.

For reference, our SBIR submission was over 200 pages, much of it containing _incredibly_ specific technical documentation about our system, clinical protocols, statistical analysis plans, etc.

Point being, it's not as simple as copy pasting a known good application.


Congratulations on (hopefully!) getting a phase 2 approved, that can be a breath of life for a lot of smaller companies.


Sodium-cooled reactors have a long and troubled history.

* Sodium Reactor Experiment (Leak, minor sodium explosion, decommissioned)[1]

* Monju Nuclear Power Plant (Sodium fire, never worked properly, decommissioned)[2]

There's even been a sodium fire at a solar plant, one of those big focused mirror systems.

Many of these new reactor designs are based on complex arguments that the worst-case accident doesn't require a huge, expensive secondary containment vessel capable of containing a major accident. That's a tough sell, since Chernobyl didn't have a containment vessel and Fukushima's reactors had ones that were too small. On the other hand, Three Mile Island had a big, strong containment vessel, and in that meltdown, it held, containing the problem. In all three accidents, the actual accident was worse than the design maximum credible accident.

The NRC is right to be skeptical of weak containment designs.

It's frustrating. The reactor designs that have worked reliably for long periods are very simple inside the radioactive portion of the system. Sodium reactors had leaks and fires. Pebble bed reactors had pebble jams. Helium gas-cooled reactors had leak problems. Molten salt reactors include a radioactive chemical plant. So nuclear power is stuck with water as a working fluid.




EBR-II and FFTF were 100% successful in the USA. Russia has also had very good experience with fast reactors. Sodium fires are a problem, but fires happen in industrial facilities all the time, you just detect them and then you put them out.

Monju had many things wrong with the design, it was a loop-type reactor that nobody is talking about building anymore. Also it was nowhere near adequate from a seismic perspective it is kinda shocking they were allowed to build it at all.

Water reactors have no future for the same reason nobody has built a coal plant since 1980. The steam turbine and associated heat exchangers are unacceptably large and capital intensive compared to modern fossil fuel power plants based on gas turbines. (Look at how huge the steam generators are for the PWR)

Even if the construction problems were solved for the LWR, the economics will not work, you are better off capturing the carbon from a fossil fuel gas turbine plant and pumping it underground.

For nuclear power to be competitive we have to develop closed cycle gas turbine powersets. The 1970s model was that a fast reactor would be more capital intensive than an LWR but with the CCGT advanced reactors could be possibly be competitive -- if we can develop the powerset and reactors that run at high enough temperatures (not water) to support the powerset.


> Water reactors have no future for the same reason nobody has built a coal plant since 1980. The steam turbine and associated heat exchangers are unacceptably large and capital intensive compared to modern fossil fuel power plants based on gas turbines.

Hmm, seems China, India and Indonesia are still building them at a rate of one per week or so, unfortunately. Heck, even Germany opened a new coal plant last year.




Not all MSRs have the radioactive chemical plant, just the thorium-fueled ones. Several MSR companies are working on uranium-fueled versions; e.g. Terrestrial Energy, where the reactor core is a sealed can that gets swapped out every few years.


I am a fan of the can.



France has recently given up entirely on fast reactors, mothballing their proposed new program.

In addition to be bad news for fast reactors, this also means France does not see nuclear being a major factor in avoiding global warming (a nuclear powered world using burner reactors would run out of uranium very quickly, or would need to tap vast new sources at dubiously low cost.)


> So nuclear power is stuck with water as a working fluid.

Steam explosions :|

Isn't a sodium fire suppressible by throwing powder/foam on it?

Isn't a containment building that can dump powder on a fire much cheaper than one that is able to withstand explosions?

Also there are non-flammable salts (eg. FLiBe)?


"Molten salt reactors include a radioactive chemical plant"

So.... what happens with solid fuel rod processing that is any different?

Well, I guess they just bury it rather than trying to consume all the fuel?


Here's some footage of Monju - pretty scary:


I think all reactors are evil until proven otherwise. Avalanches and natural disasters happen.

Do we really want nuclear anything in remote areas without human guards? What if someone decides they might like to cause an unnatural disaster?

Everyone says nuclear is safe... but where's the proof it would still be safe without the level of hand wringing we currently have?

If someone wants to do nuclear, they have to prove it's safe. Move fast and break things has no place here.


I can't say what kinds of security analyses we had to do to meet regulatory requirements, because there's a host of things you have to do to even know what security requirements there are. That's not even close to publicly available, for good reason.

I can say we have to analyze to massive vehicle bombs, armed assault, etc.

Here's what the possibly interesting, counterintuitive analysis showed. If you have a plant where a massive bomb can't cause damage to exceed regulatory standards (...we are talking about a truly miniscule amount of material here in this micro fission powerhouse in comparison with the nuclear plants you are probably thinking of... literally not more than a meter tall and wide, underground, below layers and tonnage of concrete and steel) and if an armed assault can't cause damage like that either, are you doing a favor by having a host of armed people on site? Probably not, in fact. Insider risk is then too large. There you go!

(totally agree with no "move fast and break things" here. I'm about 8 years into working on this company and still see many years ahead. we wouldn't be doing anything great if we weren't bringing forward the safest emission-free power plant to reality)


> Move fast and break things has no place here.



This is exactly why I always find it fun to read discussions about nuclear power on HN. Lots of people here are hardwired to only think in terms of software (where it's all 1s and 0s and you can do whatever you want), and then they apply that thinking and logic to real world engineering fields and the logic collapses. Doubly so for the nuclear sector because you can cause catastrophy if you aren't careful.


The question that should be asked is if the faults of the application is severe enough that its worth continuing burning fossil fuels until/if there is a new and better source of energy. That is the counter part when determining a balance between the need for strict regulation and risk assessments. The damage we know we are causing with known technology, or the damage we might cause with new technology.

We have this kind of cost-benefit assessment in other regulations. It is always a trade off between the benefit of having them vs the cost of not allowing it, be it a new food safety restrictions or building codes. A replacement for diesel generators might be worth a slightly higher risk given how much damage those fossil fuel generators do to the environment, and the global commitment to prevent climate change.


That question does not need to be asked. Nuclear power is dangerous and needs to be done with extreme care and extensive regulation. A worst case nuclear disaster can have local and not so local effects which are worse, sooner, and longer lasting than any global warming threat. If you are careful those things don’t happen.


Nuclear accidents contaminate a few thousand square kilometers for a few hundred years at the very worst. Global warming threatens the stability of the whole ecosphere and carbon dioxide levels in the atmosphere decrease in timeframes on the order of tens of thousands of years.


Alternatively, “we asked that question and the answer is ‘yes’.”


If you're competent and do your job correctly then it's possible to get NRC approval on the first try. Doing it right doesn't have to be slower or more expensive.


We can keep working on these reactors for another ten or fifteen years while we put maximum effort into building PV and wind turbines and electrifying everything. It's easy to have 50% renewables on your grid with essentially no storage at all. The world is very far away from getting 50% if its energy needs from renewables.


> if the faults of the application is severe enough that its worth continuing burning fossil fuels until/if there is a new and better source of energy

You make it sound as if the only two options we had were to build these reactors or to burn fossil fuels. These are not the only two options that you have.


Can you say more about this? I'm glad the top comment here is actually about the application itself and would love to read more about this.


You can access Oklo's public combined license application at, and read more about what's next for Oklo here -


> There are good answers to that in the U.S. and Russian experience.

What are your personal favorites of what those good answers are? One write up I found [1] doesn't go into much engineering details, and I find similar high-level descriptions elsewhere.

This reminds me of a documentary I once saw about what seemed to me a completely balls-to-the-wall experimental lab (the best kind) studying the earth's magnetic field by rotating a 12+ ton ball of molten sodium.

The way they solved the fire question was by suspending dewars of liquid nitrogen above the ball of death metal. The only way I could think of to improve upon that is a passive trigger design, wrapping the ball with walls of dewars with spring-loaded lids that open up when pressure drops below the level that the liquid nitrogen is normally contained at. If one is breached, they all breach at the same time enveloping the entire sodium footprint.



Sodium fires are often flashy but not that bad. They look scary because they form hot aerosol particles that radiate a lot of light and heat. It's nothing like a hydrogen fire you might walk into before you see or feel anything.

Sometimes you spill a few liters of sodium and it goes poof and makes some caustic aerosol you have to clean up. If the heat exchanger with a carbon dioxide secondary pops it forms a crust that will probably keep the carbon dioxide inside. Even if a water tertiary heat exchanger develops a pinhole leak the reaction happens on a 2-d surface and develops more slowly than you might think it would.

Russians documented hundreds of fires at a reactor in the 1970s most of which were little poofs, they kept calm and carried on because the prize is clean energy to power civilization for 1000s of years.


Every time I hear "liquid sodium" I think "run away!" How in the world would you make that safe even without the nuclear stuff?


(1) Argon cover gas

(2) Fires happen all the time in industrial facilities. You detect them and put them out. US and Russian literature tells you how it is done. EBR-II, FFTF and BN-800 point the way. Japan shows you how not to do it. (Not detect the fire for a long time, lie to the media about how bad the damage was)


> Fires happen all the time in industrial facilities. You detect them and put them out.

When we're talking about sodium fires in a nuclear facility, though, this comment reads to me like possibly a wry joke? I'm not even 100% sure it wasn't one, so apologies if I am responding inappropriately. It rather reminds me of an emergency physician I know who likes to comment that gunshot wounds are easy to treat; it's mostly a matter of plugging the hole. He enjoys seeing how saying it makes people squirm.


> You detect them and put them out.

Well, not molten sodium. You don't put it out. You isolate the fire and let it run.


Keep it inside the box I suppose, same principle as keeping the nuclear stuff safe.


Sometimes you open the box. There could be 'cartridge reactors' that live in a stylish hutch and only get opened at the factory, but if this is the first one they will probably need to open it and poke around inside for some reason.

Even if it only gets opened at the factory then you have to worry about the factory.


The classic Rickover quote, from the 1950s:

An academic reactor or reactor plant almost always has the following basic characteristics: (1) It is simple. (2) It is small. (3) It is cheap. (4) it is light. (5) It can be built very quickly. (6) It is very flexible in purpose. (7) Very little development will be required. It will use off-the-shelf components. (8) The reactor is in the study phase. It is not being built now.

On the other hand a practical reactor can be distinguished by the following characteristics: (1) It is being built now. (2) It is behind schedule. (3) It requires an immense amount of development on apparently trivial items. (4) It is very expensive. (5) It takes a long time to build because of its engineering development problems. (6) It is large. (7) It is heavy. (8) It is complicated.

The tools of the academic designer are a piece of paper and a pencil with an eraser. If a mistake is made, it can always be erased and changed. If the practical-reactor designer errs, he wears the mistake around his neck; it cannot be erased. Everyone sees it. The academic-reactor designer is a dilettante.

"Little that’s happened in the 60 years since suggests Rickover was wrong." -- Kennedy Maize, 12/30/2014, Power Magazine contributing editor.


My favorite pithy quote is "In theory, it works in practice; in practice, it works in theory."


And the corollary, "In theory, theory and practice are the same thing. In practice..."


Here's the denial letter to Oklo directly from the Nuclear Regulatory Commission:

All Oklo application documents linked to from this top level page:

While searching World Nuclear News for background about Oklo I ran into this story:

"Oklo to power bitcoin mining machines"

This is dubious on a couple of levels. Micro-reactors like Oklo (1.5 megawatt electrical output per unit, compared to 1000+ megawatts for Generation III reactors currently being built) would be hard pressed to produce electricity suitable for an industry that seeks globally-cheapest prices. Announcing a "20-year commercial partnership" to supply 100 units to a mining firm, before they've built a single unit, is optimistic to the point of recklessness.

The Oklo founders [1], Caroline Cochran and Jacob DeWitte, have no industrial experience, according to their LinkedIn profiles. They met at MIT while TA'ing and went straight from graduate school to founding Oklo.

I just don't think that Oklo knows what they are doing.



Ultimately I do not know whether Oklo and/or their founders know what they're doing, though I hope for the sake of the planet that they do and they succeed.

But calling them out for having no nuclear industry experience seems somewhere between aggressive and wrong. Both founders have graduate degrees in nuclear science from MIT and have been in the nuclear industry _at Oklo_ for the better part of a decade. A quick LinkedIn search also shows that Oklo employs other people with nuclear industry experience, including at the NRC itself.

If someone had a PhD from MIT in machine learning and then worked at Google doing machine learning for 8 years, would you say that person has no machine learning industry experience? At face value such a person would seem like a plausible expert!


I mean that they've never been at an organization that actually builds reactors or reactor components. Building working machines, at scale, at a price that customers can afford, is hard even if you're not in a heavily regulated industry. I'd also be skeptical of the chances for a pair of people to successfully move from graduate research in solar technology at MIT to commercializing a new solar cell design through their startup.


Hah, it's the opposite of "you need 5 years of experience in a 3 year old technology": they need X years of experience in an industry that has been dead for the last 40.


There aren't any organizations that build reactors though. You'd have to go to France or China.


> I hope for the sake of the planet that they do and they succeed.

The planet doesn't need nuclear. It just needs a concerted push to roll out renewables on a bigger scale and invest into promising long/medium term energy storage solutions (like various gravity storage solutions)

The opportunity costs for nuclear are just way too high.


> invest into promising long/medium term energy storage solutions (like various gravity storage solutions)

Since when is gravity storage a promising solution for powering the national grid?


If they started an ML company that applied for grants and failed to supply the required information, it would be acceptable to inquire about their expertise.

Academic experience does not equal Industry experience.


Nuclear powered bitcoin mining. How is the human race so smart, yet simultaneously so so dumb?


Sometimes you have to attach yourself to dumb ideas to sell the smart idea. There's a good chance these folks don't care about cypto at all and are just using this to obtain further investment and survive another day.


"We want to build a nuclear reactor to supply energy exclusively to _____." is an easy blank to fill.


Bitcoin mining is actually a really interesting use case as induced demand for a nuclear reactor which cannot easily lower its output beyond a certain threshold. Currently, fossil fuel plants are spun up and shut down to match demand for electricity, if our grid was entirely solar, wind, and nuclear, supply cannot be regulated, but by turning bitcoin miners on and off, you can regulate demand. There are other ways too, of course, such as grid connected EV chargers, but the nice thing about bitcoin mining is that the utility company can operate it themselves and use the revenue from mining to subsidize the construction and operation of the nuclear plant.


From what I understand the purpose of the mining operation is to keep the grid "balanced". "Bitcoin solves this" loses its luster a little when you compare it to running a data center next to that plant, without implicitly gambling the financial success of the nuclear investment on the continued value of bitcoin.


If it displaces fossil fuel based Bitcoin mining that's still a net gain in my book.


Our intelligence is dwarfed by our unlimited greed.


We’re more properly Homo callidus, not Homo sapiens.


They want to put this in the middle of nowhere in Idaho. It wouldn't be worth running transmission lines to connect a reactor this size to the grid.

You could put the bitcoin mine right next to the facility and do something useful with the electricity. It really should be coupled to some real sink so they can see the dynamics of the reactor + powerset + consumer.


Before people jump down your throat with pseudo ethical pearl clutching, just replace "do something useful" with "generate income".

You don't have to personally believe that bitcoin mining is "useful" to acknowledge that it certainly can generate real money to offset the cost of a remote experiment like this one.


I have to admit I'm amazed how sentiment on HN against cryptocurrency has turned sharply negative.

I think a year ago we were comfortable with Bitcoin as a store of value but the NFT craze has made almost all of us adopt the "right-clicker mentality".

Years ago I was an INTP but something happened to me a year ago and I got into doing art projects and I lately scored as an INFP. I told my therapist the other day that, more than anything else, I want to plant my feelings like seeds, intensify and cultivate them, compress them into a ball, throw it at somebody and have it hit them like a lighting bolt.

NFT people drive me nuts because (1) I'm not that good at art, (2) I want to get much better, (3) I know I'm going to do that by really emotionally connecting with people and (4) I can't know I'm really doing it with people who are blinded with NFT greed. (Look at the sh1t they buy!)


"The Oklo founders [1], Caroline Cochran and Jacob DeWitte, have no industrial experience, according to their LinkedIn profiles."

So Theranous all over again?


Having read possibly too much Matt Levine my first thought wrt the Bitcoin things was "this is an investor relations move".


Hand picked by Sam Altman. Lol


> no nuclear plant that has submitted an application since the formation of the NRC in 1975 has yet commenced operation.

Wait, what? I knew that reactor construction stopped around then. I hear it alluded to often enough, e.g. "US grid could have been 100% low-CO2 power by now if we had just kept up the pace of deploying nuclear instead of stopping in the 80s." Still, I thought the story was a messy mix of regulations hitting at the same time as city growth was topping off and interest rates were skyrocketing.

If the NRC just says "no" to everything, that's a big deal. Is there more to the story?


The NRC said "yes" to 4 new AP1000 reactors in Georgia and South Carolina more than 10 years ago. They were all supposed to be completed years ago. The South Carolina project was abandoned after cost and schedule blowouts. The Georgia project continues to chug forward despite similar cost and schedule blowouts. Here's a brief synopsis of the Georgia project:

On August 26, 2009, the Nuclear Regulatory Commission (NRC) issued an Early Site Permit and a Limited Work Authorization. Limited construction at the new reactor sites began, with Unit 3 then expected to be operational in 2016, followed by Unit 4 in 2017, pending final issuance of the Combined Construction and Operating License by the NRC. These dates have since slipped to 2022 and 2023 for Units 3 and 4, respectively.


Right, but one interpreation of this fact is that they set the bar for compliance too high, so it's almost impossible to finish a reactor in a financially feasible way.

Unfortunately, there seems to be no way for our society to overcome the apparent moral high ground that nuclear skpetics hold. Nuclear disastors are too good at capturing the imagination and all a skeptic has to say is "you can never be too safe."

Meanwhile, we claim that our reliance on fossil fuels is a disastor, but if it's not enough of a disastor to compel us to make nuclear regulatorily viable, how much of a disaster can it really be?


It not being financially feasible to finish a reactor and comply with the regulations doesn’t mean they’re set too high. Maybe it just means you can’t have safe AND financially feasible nuclear right now.


Thanks for the context!

Yeah, that syncs up better with my intuition: disasters plus bad economic timing killed the industry in the 80s and it hasn't gotten back on its feet because big projects are hard enough with momentum and the industry has to start over from zero.

Here's hoping they can get back on their feet!


Westinghouse Electric Company (the reactor manufacturer) took over construction management in 2015 after the first constructor botched schedules and costs. Westinghouse subcontracted to Fluor. In 2016, adding Bechtel.

In 2017, Westinghouse declares Chapter 11 bankruptcy from construction losses, and the final owner Southern Company reselects Bechtel as the construction manager.

Current operational date looks like 3Q 2022, and on track.

tl;dr - Don't allow megaproject management experience to atrophy. The US military learned this (see: how the Navy builds carriers and nuclear subs). Have a prime and a secondary. Rotate. And, for god's sake keep the pipeline full. Skills atrophy and knowledge is forgotten.


The South Carolina reactors were abandoned. Vogtle looks on track to spin up this year. Vogtle was held up a long time because the index reactor of the type in China was held up while the factories were taking a while to figure out how to make the parts.

In so far as a water reactor could be practical (awful economics of the steam turbine and steam generators) the AP1000 looks pretty good.


How is it that four AP1000 reactors are built and running in China, that the companies building nuclear reactors have a long and apparently successful history of providing reactors to the US Navy, and yet trying to build two in the US bankrupts the company?


One of the advantages of China's large and diverse reactor programme is that when they are building FOAK designs and something comes up that holds up the work (as it did on both their AP1000 and their EPR builds), they put their nuclear qualified workforce on buses and move them to other builds.

Compare that to Flamanville, Olkiluoto, and the US AP1000 builds where every time there was a work stoppage to review a detailed design element, a massive and expensive workforce just had some paid chill time.


If I had to guess, neither China nor the US Navy care about generating a profit from the reactors.


There used to be four under construction in the US. Those in South Carolina were left partially built instead of spending even more money trying to complete them after the project went off the rails. Regional newspapers have gone into great depth explaining what went wrong. Here's a recent article from the Atlanta Journal-Constitution about problems building the Georgia reactors:

"How Georgia nuclear project’s big finish went so wrong"

There were even worse problems in South Carolina that actually led to federal criminal convictions:

"Former Westinghouse Executive Charged with Conspiracy, Fraud in Connection with V.C. Summer Nuclear Project"

Former Westinghouse Electric Co. Senior Vice President Jeffrey A. Benjamin was charged with 16 felony counts, including conspiracy, wire fraud, securities fraud, and causing a publicly traded company to keep a false record, for his part in failing to truthfully report information regarding construction of new nuclear units at the V.C. Summer nuclear plant in South Carolina.

Benjamin is the fourth individual to be charged in the ongoing federal investigation. Former SCANA CEO Kevin Marsh, former SCANA Executive Vice President Stephen Byrne, and former Westinghouse Vice President Carl Churchman have all pleaded guilty to federal felony charges for their roles in the matter.

Here's a big investigative series that the Charleston Post and Courier did about the problems with the VC Summer expansion in South Carolina:


See this chart:


Apparently they approved NuScale's Small Modular Reactors:

NuScale spent over $500 million and more than 2 million labor hours to compile the information needed for its design certification application.


> If the NRC just says "no" to everything, that's a big deal. Is there more to the story?

The NRC doesn't say "no" to everything; AP-600/1000 designs were approved, an SMR design has been approved. The NRC is entirely willing to approve competent design efforts.

The most candid explanation of the attitude of the NRC was offered by former chairman Dale Klien and his "no bozos" baloney test; there is no room in nuclear power for hucksters and the NRC won't indulge them. This rejection is evidence that this mentality still prevails; failure to respond to NRC questions about reactor design in a timely manner is bozoery and this is the correct outcome.

The Oklo proposal isn't some generational variant on PWRs. They are proposing a fast breeder. You can't go to the NRC with a fast breeder application on anything less than a multi-billion dollar R&D operation designed to positively thrill the NRC with actually epic levels of competence and preparation and expect to be approved, and that is exactly how it should be.


What stopped the first nuclear buildout in the US was a combination of things. One is that the 7%/year growth in electricity demand suddenly moderated. This caught some utilities by surprise; if they had many NPPs in process they were in for pain (WPPSS went bankrupt). Another is the passage of PURPA in 1978, which started to open the grids to non-utility power. Cogeneration started to take off then. Any industrial activity that needed heat could now drive a combustion turbine and sell some power at low marginal cost, using the waste heat for their need. There were also some cogeneration-in-name-only non-utility plants that were mostly just to make power.

All this made large, new, expensive nuclear plants difficult to justify. TMI was just the icing on the cake.

The more recent "nuclear renaissance" died because natural gas become very cheap (and a combined cycle NG power plant costs $1/W to build; a factor of 10 cheaper than a nuclear plant) and because nuclear construction was more expensive than promised (bye, Westinghouse).


To be fair natural gas is only cheap because the cost to the environment isn't factored in. The cost of nuclear power is pennies when compared to the decimation global warming will bring to the human race.


Even so, natural gas in the US is so cheap that the CO2 charge that would be needed for new nuclear to compete would be very high, so high that very large CO2 emission reduction would occur elsewhere first.


“The cost of new nuclear is prohibitive for us to be investing in,” says Crane. Exelon considered building two new reactors in Texas in 2005, he says, when gas prices were $8/MMBtu and were projected to rise to $13/MMBtu. At that price, the project would have been viable with a CO2 tax of $25 per ton. “We’re sitting here trading 2019 gas at $2.90 per MMBtu,” he says; for new nuclear power to be competitive at that price, a CO2 tax “would be $300–$400.” Exelon currently is placing its bets instead on advances in energy storage and carbon sequestration technologies.


Reminds me of that FDA reviewer who refused to approve any drugs on the grounds that risk couldn't be completely eliminated.


A common solution to the Trolley Problem.


got a link?


Below your quote, it says that NuScale has gotten approval. It’s not that nobody has gotten approved, it’s that nobody has commenced operation.


NuScale will, after about 15 years of engagement, receive a design certification later in 2022. After that- they will still need to apply with a combined license application like Oklo did.


Each of the words there happens to be significant.

- plant: plants that had reactors first approved earlier have since had reactors approved that will commence operation soon (Vogtle is the classic)

- commenced operation: designs exist that have been approved but haven't commenced operation

One could argue that the NRC only approves commercially unviable designs or something like that, I suppose. Or that we have just as many plants as we need and we just need more reactors. Or that the general stance of the public has shifted away from nuke.


You're misreading the claim. It's not that they have not given any approvals, it's that those reactors did not go on to reach operating status. That means these are more likely to be business problems, not regulator problems.


I don't think it makes sense to talk about the business of building nuclear reactors as something separate from regulator problems. The two are very tightly intertwined.

Four AP1000s are operating in China right now, demonstrating that under different regulatory regimes, the plants can be built.


The question then, is whether a Chinese regulatory regime (or any other sort of Chinese regime) is something the US should aspire to emulate.


I don't get why the first response of the startup is to go on the attack and fight the NRC without responding to the substance of the claims. This is the part of startup behavior I really dislike. Fake it till you make it and be loud and boisterous and brash but still deflect and push vague promises. It's hard to put the required trust in these companies when they react like this. Don't they want people to trust their offering? Especially in a market where trust is everything? Calm down startup founders and stop blustering your way to "success".


This behavior is rewarded in the world of founders though. It’s always fun to watch people like this confront serious regulation. I once advised a startup that had to deal directly with HIPAA and the petulance of these MBAs was honestly kinda funny.


Oklo's response...

>We woke up a few days ago to incredibly surprising decisions by the NRC. Although Oklo responded to every request for information, and the last thing we heard from the NRC was that the information we submitted was helpful, the NRC has denied our first application on the basis of not having submitted information. The NRC has now gone from having one combined license under review to none.


I find their public response unprofessional and immature. The Nuclear regulatory process is similar to other federal and international public-safety regulatory processes such as aviation, medical, and wireless: companies soon learn that it is best to work with the regulations and regulators and not fight them.


A relative of mine with the background to have an opinion on it once told me about how companies were vaporizing millions and billions of dollars for not properly cooperating with regulators and it was just baffling to them.


In reading over this, I honestly became more worried about the prospect of this company building nuclear reactors than before I read it. This is not a professional response that breeds confidence. It is... petulant.


> Oklo will respond to the NRC letter with a letter clarifying things that cannot be left the way they were characterized. So you will see that soon. But mostly, we want you to know that we are moving ahead. With your support, this will generate positive change. This is a distraction, but it may ultimately enable us to move ahead even faster. We look forward to continuing to share more about what is next for us as we move forward!

Did they even run this article by a copy-editor? It's pretty poorly worded, like one of the founders stayed up until 3am to pen this post.


Wow, that part of the response just sounds unhinged. Characterizing a response from their industry's governing body as "a distraction" is immensely concerning.


I'm sure that phrasing will endear them to the NRC.


It's funny given what the NRC letter says about that same time period:

> The staff determined that neither topical report contained sufficient information to initiate detailed technical reviews. Each report contained conceptual information, rather than repeatable methodologies, and each left many issues unresolved and open for future potential applicants referencing the topical reports to address. The NRC staff informed Oklo of the insufficiency of the topical reports by two emails dated August 5, 2021 (ADAMS Accession Nos. ML21201A079 and ML21201A111), that included attachments describing in detail the supplemental information Oklo must provide for the NRC staff to begin the detailed review of each topical report.

> By letters dated October 5, 2021 (ADAMS Accession No. ML21292A325), Oklo submitted revised topical reports for the MCA and PBLM methodologies. The NRC staff conducted a completeness review of the revised topical reports and determined that Oklo provided no new substantive information and failed to fully address the information gaps identified during the original completeness review and discussed during public meetings

There are also a few places on the NRC letter that hint at the NRC's frustration with Oklo:

> letter dated November 17, 2020 (ADAMS Accession No. ML20300A593), the NRC staff informed Oklo that Step 1 was completed for the area of applicability of regulations. The NRC staff’s Step 1 review focused on regulations Oklo identified as not applicable to its Aurora design and did not evaluate the acceptability of requested exemptions. By letter dated December 21, 2020 (ADAMS Accession No. ML20357A002) Oklo informed the NRC staff that they intend to pursue further engagement on the topic of applicability of regulation


> On December 2, 2020, during a routine scheduling call, Oklo requested that the NRC staff temporarily pause its review and stop developing additional RAIs for the Aurora custom combined license application;

> The NRC’s docketing decision for the Aurora custom combined license application was designed to obtain the necessary additional design information from Oklo and complete Step 1 activities within five (5) months. The NRC staff engaged extensively with Oklo to complete Step 1 through numerous meetings and by conducting audits, requesting additional information, and clarifying its information needs. More than a year has passed since the application review commenced, during half of which the technical review was paused at the applicant’s request. Oklo’s proposal to develop generic methodologies to address the topics of MCA and classification of SSCs was not successful in closing Step 1 of the review, and foundational issues identified during the Aurora custom combined license application acceptance review remain unresolved. Accordingly, the NRC staff is unable to complete Step 1 of the two-step review, or establish a reliable and predictable schedule.

Given that, I sure hope that cooler heads at Oklo prevail and they don't follow through on:

> Oklo will respond to the NRC letter with a letter clarifying things that cannot be left the way they were characterized. So you will see that soon.

That really doesn't seem the way to resolve the issues Oklo is having with the NRC.


This is a huge issue for nuclear power generally. It is incredibly expensive to navigate the regulations. Oklo thought they were good and now they need to spend millions and millions more to apply again. (I’m assuming good faith on Oklo’s part). I really think there needs to be serious reform at the NRC.


You call it an issue, I call it a boon.

I do not want nuclear power approved quickly, or easily. I want it to be burdensome, difficult, and with a massive requirement for proving out safety in even the most unlikely of scenarios.

This area does not need Silicon Valley style disruption at the cost of endangering lives and destroying the earth.


This is very much "status quo" bias, as if the current state of the world were not endangering lives and destroying the earth.

People talk about climate change in apocalyptic terms until it actually matters in real world decisions for things other than the things they wanted to do anyway.


>This area does not need Silicon Valley style disruption at the cost of endangering lives and destroying the earth.

We are currently destroying the earth because we are stuck using technology from the 1800s to power our 21st century society. Yes we do need silicon valley style disruption.

Give them a pacific atoll, or an old oil drilling platform, and let them do whatever they want.


We have the tools we need, already, to avert the catastrophe.

Problem is it will cost the rich and powerful a little opportunity cost and a bit of wealth.

The looming climate catastrophe has political and social solutions. Not technical ones.


I do not thing regulatory hurdles are what's stopping us from building more nuclear plants but public funding and will. So if a bored billionaire wants to enter this space, he won't be stymied by the approval process or need to sidestep it.




The article is really sparse on what information was missing. Neither the NRC or Oklo specified what else is needed. It’s probably wise to give both sides the benefit of the doubt.


While the article doesn't reference all these details, the NRC's denial letter to Oklo covers more of them:

The claim from the NRC in that letter is:

“Oklo’s application continues to contain significant information gaps in its description of Aurora’s potential accidents as well as its classification of safety systems and components,” Veil said. “These gaps prevent further review activities. We are prepared to re-engage with Oklo if they submit a revised application that provides the information we need for a thorough and timely review.”

(phew, that PDF does not copy/paste text cleanly, at least not in Safari. Had to re-type it.)


That sounds reasonable to me.


Pertinent info FTA:

Oklo co-founder and COO Caroline Cochran pointed out the stunning fact that no nuclear plant that has submitted an application since the formation of the NRC in 1975 has yet commenced operation.

Assuming accuracy, that's a damning statistic. I don't believe for a minute that every single application that's crossed their desk for nearly half a century was so flawed or unsafe that it was unworkable.

Knowing what I know of governments and bureaucrats, I'd speculate that they're being asked for a bunch of irrelevant or impossible (i.e. doesn't apply to their design) information, and the people in the bureau are being useless and obstructive about it since there's no downsisde for false negatives.


Not really, it is very specifically worded to paint the NRC in bad light. Vogtle, Virgil C. Summer and company have gotten the applications regarding their designs approved. They just haven't managed to bring the construction to a finish yet.

The NRC may be the culprit there also, but that is a completely different question.


Aren't those standard LWR designs? Have any new technologies been approved?


None have commenced operation, but NRC has approved applications for new nuclear plants.

It's easy to blame regulators, but a big factor is simply cost. For the last 20-30 years, low fossil fuel costs in the US have meant that the huge investment needed to get a nuclear plant from application to operations didn't make sense. Westinghouse Electric went bankrupt in 2017 because of it. Add in that nuclear has been very out of favor with the public, it makes it really hard to get a reactor built.


It's pretty carefully worded, even if that's true it's possible that NRC has approved lots of applications that haven't commenced operation for other reasons. It's bad regardless, but unclear if NRC is rejecting everything or if projects are failing because of other factors.


I'd imagine that the initial application is not the only touch point.


It’s not that the applications are denied, it’s that they haven’t started operation. Below that quote it mentions another company that has gotten approval.


It's a little misleading since the expansions at Vogtle in Georgia are scheduled to finish this year and next year.


That’s still 47 years assuming the Vogtle is actually finished this year.


There was an interesting discussion of this on Twitter the other day when Patrick Collison posted about it:


Also part of bureaucracy is cronyism. There's a lot of big contractors working for and with the NRC who might not like any new competition.


This is one area where the normal Silicon Valley strategy of "fake it til you make it" just won't fly. I deeply hope NRC keeps shooting this down until they actually do it right. Sounds like this company doesn't really have the chops to play this game, but maybe they are just sloppy, we'll see.


Oklo has the competency to pull this off. This is 50 year old tech and is not hard to build or operate.


Oklo should proudly resubmit asap. This is clearly procedural to reset the NRC’s application timer.

Oklo can go back and forth with the NRC 10 more times for all I care. A 1MW generator is disruptive microgrid tech, worth the wait.

Oklo’s inventive application is stirring the pot. People are talking. Culture is shifting. NRC is working and being forced to grow.


The article is certainly bias towards the move fast and break things mentality being applied to these nuclear startups. It basically calls the NRC a dinosaur that's blocking any future nuclear capacity, which in my mind IS a big party of its mandate. Is this canary media and industry outlet? This reads like an editorial


Thankfully, the situation is more nuanced and better researched than Canary implies. This is what forward progress looks like for clean energy


It's great to see more thinking, that said, the issue with Nuclear is 'proliferation' which greatly increases risk.

I'm very skeptical of microreactors from that perspective: lower overhead, smaller businesses don't have the economies of scale to have all of risks mitigated. Surely most of them well, but it's the 1% 'cutting corners' that makes it a problem.

A whole host of other problems arise in the more expansive categories, but at least at a certain scale, I think there can be more comprehensive oversight, down to having 1 or 2 regulators on site at all times. I think there are only 50 Nuclear reactors operational in the US, so that's limited scale.

Especially in developing countries with weak oversight, it keeps the bar high.

A large nuclear facility in Mexico that happened to be near Gang Turf ... if there was a problem the Federales could step in and worst case scenario literally US Marines.

But 1000's of mini nuclear facilities all over North America ... that should give us pause to contemplate the systematic risk.

And FYI spent nuclear fuel also sits at these installations for some time as well. How much security can be justified at a tiny, 'micro facility' vs. a more mainstream facility?

I wonder if even this reactor design passes muster, if the actual construction and operation of such a facility would also pass muster ...


Real science investors with access to high level nuclear talent never seemed to think much of this company.

Its financing seems to be Koch Industries, through a strange sort of PR/VC arm they have.

The denial is substantive. I am pro fission but, erm, would rather go with Westinghouse.


You don’t sound pro-fission. This is a novel 1MW micro-reactor with major policy implications that merits public support.

Westinghouse and other large reactors have a totally different use case thank Oklo’s design for remote communities.


No, Westinghouse has designs for small reactors too.

One prob with oklo seems its amateurish funding and founding. The other is that maybe 1 mw isn’t so useful. 100mw makes a difference (with distribution), so does 50kw (without distribution.)

What is 1 mw for? An airport, maybe?