We almost built 8 gigawatt-class floating nuclear power plants | Hacker News Reader

We almost built 8 gigawatt-class floating nuclear power plants

whatisnuclear.com

93 pointsperihelions34 comments

We could still do this, or something almost equivalent.

This 2011 CBO analysis [1] looked into the feasibility of outfitting US Navy surface ships with nuclear reactors. The US Navy is known for burning more fuel than some small nations. The conclusion of the study was that it's not worth it, but they did not consider CO2 emissions at all.

On page 10 this study implies that the cost of building an A1B nuclear reactor (one of the 2 powering a new Gerald Ford carrier) is about $0.9BN. This cost is classified, so this number is as close as you can get to the real cost. The power generation capacity is also classified, but you can infer it could be about 400 MW. So, that's a cost of about $2.5 BN/ GW.

This cost is not available to everybody, but it certainly is available to the US Navy. It's conceivable the lawyers could find some loopholes to make it available to the Department of Energy as well.

So, if Congress is serious about climate change, they can easily mandate the US Navy and the DoE to order a bunch of A1B power plants, and use them to replace conventional power plants or provide clean electricity. There's simply very little that prevents Congress to do that. The technology is there, there's nothing to innovate. The economics make sense. The safety of the US naval reactors is simply unparalleled. In 70 years of service they did not have a single incident. The manufacturing capacity is there; the US is already making about one such reactor per year, they can increase that to 10 per year in a decade without any issues.

[1] https://www.cbo.gov/sites/default/files/112th-congress-2011-...

It's not obvious how to translate this figure into a standalone plant cost. The COB study is quoting the acquisition cost premium of a nuclear ship over a non-nuclear ship. I believe that estimate is the premium for taking a non-nuclear design and adding a nuclear reactor to it, so it does not include a lot of plant infrastructure that is part of the cost of civilian power stations. Also I would think the requirements for the containment structure and safety systems would be significantly different.

Fair enough. Currently each America-class ship [1] uses 2 GE LM2500 turbines [2]. This type of engine has been produced in huge quantities, more than 2000 to date. The unit cost is about $11 MM [3], so it's negligible compared to a naval nuclear reactor.

Where a nuclear reactor comes ahead is the fuel cost. Which is zero (it's included in the construction cost, and there's no refueling for the lifetime of the ship). A conventional turbine burns fuel, and over the lifetime of a ship it can add up to quite a lot. It can certainly get above $1BN.

In fact, the CBO analysis shows that the total cost for 5 such ships would be $14.2 BN using conventional engines, and $14.8 BN using nukes ([4] page 6 top table). That was when the oil price was $86/barrel. Now it's $110, so just because of that the calculus can switch to favor the nukes.

[1] https://en.wikipedia.org/wiki/America-class_amphibious_assau...

[2] https://en.wikipedia.org/wiki/General_Electric_LM2500

[3] http://www.fi-powerweb.com/Engine/Industrial/GE-LM2500.html

[4] https://www.cbo.gov/sites/default/files/112th-congress-2011-...

One of the first commercial US PWR nuclear reactors was a burred in the ground nuclear powered air craft carrier plant. It was built by the AEC under the direct supervision of the Navy. https://en.wikipedia.org/wiki/Shippingport_Atomic_Power_Stat...

Indeed. It was originally a prototype for an aircraft carrier engine, but the Navy was waffling on whether or not it needed such things. So Rickover led its development as a commercial demo instead, and it worked better than most of the other more exotic reactor types being tried at the time, and so now we have mostly this kind of reactor in the world (the PWR), and its close relative (the BWR).

Later the Navy decided that they did indeed want nuclear powered aircraft carriers, and so now they have them.

> The safety of the US naval reactors is simply unparalleled. In 70 years of service they did not have a single incident

And how do we know that for sure, given the army tendency to cover up wrongdoing?

https://en.wikipedia.org/wiki/United_States_war_crimes

https://en.wikipedia.org/wiki/List_of_nuclear_power_accident...

https://en.wikipedia.org/wiki/Ocean_disposal_of_radioactive_...

Not to mention the societal risk in having critical civic infrastructure controlled by the military.

Radiation detectors are incredibly sensitive and can detect even a single atom decaying. If there were a major radiological release people around the world would see it.

Two US nuclear submarines have gone down, the Thresher and the Scorpion. Neither was due to the nuclear power plant, and so far they have kept the radiation contained.

> so far

That says everything.

Keep in mind that the favorite method of waste disposal during the early history of nuclear energy was dropping containers into the ocean. This dumping strategy hinged on the dilution of the material in huge quantities of water. The strategy was successful but particularly unpopular.

If the containment on these reactors was lost, the effect would be measurable due to the sensitivity of such detectors, but literally a drop in the bucket of waste disposed of into the ocean.

http://large.stanford.edu/courses/2017/ph241/jones-a2/

> having critical civic infrastructure controlled by the military

Hasn't that ship already sailed, with the Army Corps of Engineers being responsible for all dikes in the US?

Author here, AMA.

This post got me introduced to Ira Flatow, and we discussed it on NPR's Science Friday a while back.

https://www.sciencefriday.com/segments/floating-nuclear-powe...

I mentioned this in a thread yesterday when someone asked me what my favorite advanced reactor was.

https://news.ycombinator.com/item?id=31463673

The huge crane being sold to China in 1990 is the sad ending of the story:

https://www.tampabay.com/archive/1990/11/05/huge-crane-sold-...

Thank you for sharing! What a great article. As I read it I formulated several questions only for them to be clearly resolved as I read further. This is so often not the case.

I would be interested in learning more. Is there one of the recent development projects that is more mature and likely to succeed than the others?

Does the science Friday episode have additional information not included in the writeup?

Thanks for saying so. I'd say the writeup is more informative than the Science Friday piece, honestly.

There are a few good modern reports about using his kind of idea for making ammonia and hydrogen, but nothing too serious is going on outside of Russia and China on this topic.

[1] https://www.lucidcatalyst.com/hydrogen-report

Most of the people talking about it in advanced reactor space are using very low readiness reactors rather than PWRs, which led me to make this extremely fringe starwars prequel meme: [2].

[2] https://i.imgur.com/bDaVjRY.png

The Koreans have the PWRs and the ship industry in place, they'd be the best to make this happen again. But so far they've just done a few small MOUs here and there. Again, nothing too serious is happening from what I can tell. I'd be happy to be wrong.

Thanks again!

Interesting article, but the relative cost of nuclear vs solar/wind/storage is why utility managers around the world are not that interesting in expanding their nuclear footprint.

Often you'll see people argue that excessive regulation is what is driving costs up, but without a very high level of maintenance, nuclear power systems will inevitably have an unacceptable rate of failure. These safety margins need to be higher than those for units like oil refineries, coal-fired power plants etc., as the consequences of failure are so long-lasting (fires at oil refineries are relatively common, for example, but they don't result in 100-year no-go radioactive exclusion zones).

Therefore, to make nuclear accidents highly unlikely, maintenance costs amd engineering standards will inevitably be much greater than in any other power supply system. This means nuclear will always cost significantly more than any other system - and this also applies to storage of too-hot-to-handle 'spent' nuclear fuel, as well as to the costs of eventual decommission. In addition, the nuclear fuel supply chain (high grade uranium ore -> fuel rods) is fairly complex, and subject to geopolitical and economic price spikes.

All in all why would a utility manager these days looking at all the options for non-fossil-fuel power go with nuclear?

On cost, the simple answer is that if fossil and biofuel had to pay for the air pollution health effects they cause (4.2 M deaths/year [1]) and the climate change damage they cause, then every utility would switch to nuclear for baseload immediately. The markets are incorrect in not capturing these costs. Nuclear is dramatically cheaper than fossil and biofuel on this basis alone in a real market.

And of course the advantage of nuclear over wind and solar is that nuclear has a 92% capacity factor with fairly regular well-planned outages.

The wind and solar costs you've seen, while stellar, do not include the costs of the backup generators and batteries, additional transmission to remote site, overcapacity required to charge the batteries at scale, etc etc. Nuclear is certainly on par with them in a fully decarbonized system. In any case, building nuclear alongside wind and solar makes the whole system cheaper [2].

Regarding 100 year no-go zones, the hottest areas I see around Fukushima today measure about 30 mSv/yr, which is about 2x higher than Denver's natural radiation. Japan is lifting even more evacuation orders as we speak [3]. If they gave people the proper information about the health risks (e.g. that you need more than 100 mSv in a year before the smallest measurable cancer increase can be seen) then people would have all moved back 10 years ago.

[1] https://www.who.int/health-topics/air-pollution

[2] https://doi.org/10.1016/j.joule.2018.08.006

[3] https://sp.m.jiji.com/english/show/19741

> the costs of the backup generators and batteries

Just to put an extra-fine point on this...the backup generators are typically fossil fuel fired, so the unpaid externalities apply to those as well.

I think we want to compare nuclear and solar/wind/storage, where the base goal is to have a steady power generation rate over time (adjustable to demand within certain limits). This tends to produce a closer cost outcome for nuclear and s/w/s as storage costs (batteries, inertial storage, pumped hydro, etc.) are probably going to at least double or triple the installed costs of the s/w/s power system.

For example, if you want to provide relatively steady 1GW of power 24-7, 12 m/yr, this can be done with a nuclear plant running at its optimal rate (*optimal for fuel rod lifetime and steady burn rate). With a solar/wind system, you'd likely need enough PV panels to produce say 2GW at noon, with 1GW going to grid demand and another GW going to storage, to meet demand at midnight etc. Balancing seasonal demand in subpolar regions would require a lot more power and storage as well, so nuclear may have an advantage there.

Clearly both systems are possible, but both have supply chain issues (uranium ore and fuel elements and reactor construction, vs. battery components and PV panels and wind turbines and storage infrastructure). However, I'd guess long-term maintenance costs are going to be much lower with solar/wind/storage systems (with much lower fueling/waste storage issues and liabilities, which would really just be battery maintenance and replacement costs).

What am I misunderstanding/miscalculating? The US uses ~4000 billion kilowatt-hours [1] and these $1 Billion reactors produce 8GW. 8GW is 8 million kilowatt-hours. 4,000,000 MKWh / 8 MKWh = 500,000 reactors. To provide 20% of electricity we need 100,000 of these reactors at a cost of $100 Trillion? A quick google says:

> One hundred trillion dollars. That’s the total net worth of all Americans in 2017*.

[1] In 2021, net generation of electricity from utility-scale generators in the United States was about 4,116 billion kilowatthours (kWh) (or about 4.12 trillion kWh). https://www.eia.gov/energyexplained/electricity/electricity-...

Im on mobile so will check you math later but our 100 GW nuclear fleet makes 20% of our electricity. So you need 500 GW-class reactors to power all electricity in the USA, not 500,000.

UPDATE: So yeah power is rate of energy delivery, measured in Watts or Joules per second. Energy itself is measured in Joules or (equivalently) Watt-seconds. Units that are like kW-hour have power × time, so those are energy units. So if the USA uses 4116 billion kWh of energy in a year, that comes out to 469 GW of power averaged over the year. So you need about 500 GW-class nuclear reactors to generate the country's electricity.

Meanwhile electricity is only 40% of our total energy usage. The rest is transportation (almost all oil), building heat (natural gas), and industry (mostly natural gas). Those have to be decarbonized too, and if we switch them to electric alternatives we can expect our total electric demand to roughly double.

PS I always use GNU units for these kinds of unit conversions (`units "4116 billion kW*hour/1 year" "GW"`)

A small notes, with the premise that I favor nuclear in general, not only future hoped fusion if we will ever get it: we use electricity mostly on-shore, also deep inside land. Surely a water-born NPP can travel so can theoretically adapt to different needs, theoretically only since it still demand a land-based distribution network, surely a water-born NPP can be sunk easily in case of an emergency so it's safer BUT while I agree that due to climate change and social changes derived we need flexibility that means going via air and water instead of land since infra on land can't really be built and changed in quick enough time at a low enough costs with a low enough needs of natural resources and yes we can easily move stuff on the sea that on land, BUT we still live on land...

Also for defense needs, where possible, we want critical industries, those who most need nuclear, deep inside land to better protect them to direct military attacks...

Such floating power plants can be useful for a colonization where land can't be used like in the now melting Arctic areas where we can't safely built on soil due to it's continuous changes and we need to quickly develop infra there in a race for natural resources, they can be useful in some very seismic areas or for emergency usage in remote areas IF small enough and able to travel quickly enough (witch is unlikely) avoiding being too near the coastline to be safe in maritime terms but I fail to see other realistic usages...

It seems a bit like the '70s nuclear-powered aircraft experiments, formally nice, but only in engineering terms, and they fails as expected...

My understanding is that naval reactors mostly (if not all?) require near-weapons grade uranium. Though I assume this is to allow a compact design. How highly enriched would it need to be in this case? Any more than current land-based civil designs?

For what it's worth, here in Jacksonville, the whole thing is remembered as a world-class boondoggle. 40 years later newspaper columnists still laugh about the city and utility getting swindled on this project.

It's sad that it's been remembered that way. The alternate viewpoint that Jacksonville was this close to having the world's leading decarbonization gigafactory would be how I wish it was remembered. Since the customers for the plants bailed and the effort failed, I can see why people would rather think poorly of the effort.

I posted on the Jacksonville subreddit a while back seeking photos of the crane and other stuff. They referred me to the local library where there's a apparently a huge collection of info. It's not available online but I'm going to have to visit sometime.

It doesn't help that there is a modern-day parallel ready to go, as the utility is currently invested in a new nuclear plant in Georgia that I think is coming up on 10 years behind schedule and untold billions over budget.

Yeah, that definitely does not help. The struggles there with ramping back up a production supply chain and the appropriate knowledge to deliver those components just emphasizes how important it is to concentrate that knowledge into fewer small groups that can deliver plants around the world. The assembly line idea for nuclear plants is basically necessary.

Do you know which library?

I'm temporarily local, and should be able to go through and maybe digitize (or at least photograph) some documents, if any exist.

PS: Thanks for the research and excellent writeup. Fascinating piece of history I'd never heard about!

That would be awesome. If you do this please get ahold of me. One user told me:

> Public Library downtown in the Loyd Sandgren photo collection. I have seen photos of the "floating" plant under construction. Tough finding it though the librarians may be helpful.

And another said:

> Go to the special collections of the downtown library ask for Blount island nuclear development files.

Those work for starting points. I'll see what I can do. Does the Contact Us on whatisnuclear.com lead back to you?

yup it just emails me directly. Oh but when I reply it usually gets filed to spam (especially on gmail) because I host my own email server... so check your spam!

Rosatom started planning floating nuclear power plants in 2000 and in 2019, the Akademik Lomonosov 1 and 2 [0] entered service, producing 35 MW (150 MW thermal) each. Other than the RBMK technology used in Chernobyl, Rosatom built a PWR (pressurized water reactor).

[0] https://en.wikipedia.org/wiki/Akademik_Lomonosov

Yeah that is the most real manifestation of this kind of concept in modern days. The Russians have built and operated dozens of PWRs for terrestrial commercial applications in the past few decades as well (the VVER). The RBMK has been retired as a design since 1960 or so.

https://en.wikipedia.org/wiki/VVER

I don't really understand the concept. The plant itself is floating, but it is surrounded by a riprap breakwater. Why not just cut out the middleman and put the plant on a constructed island, which would avoid the colossal maritime issues with the project?

If the proposal was for an actual seaworthy ship design, I would understand the value in that: You could simply drive the whole thing back to the specialized factory port for maintenance, you could respond to disasters or changing economics, etc.

As is, it seems like a solution looking for a problem. I just don't see how moving the nuclear plant 3 miles off shore actually solves anything.

EDIT: Actually, I see that the plants would be removable. I didn't realize that the straight section of the seawall could be removed to get the plants out of the breakwater. Still, I can't shake the feeling that the idea of compartmentalized, serial produced reactors that are transported by barge is a great idea -- so long as they don't live on a barge too.

Solves the NIMBY problem :)

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