Since China State Shipbuilding Corporation (CSSC) unveiled its KUN-24AP containership at the Marintec China Expo in Shanghai in early December of 2023, the internet has been abuzz about it. Not just because it’s the world’s largest container ship at a massive 24,000 TEU, but primarily because of the power source that will power this behemoth: a molten salt reactor of Chinese design that is said to use a thorium fuel cycle. Not only would this provide the immense amount of electrical power needed to propel the ship, it would eliminate harmful emissions and allow the ship to travel much faster than other containerships.
Meanwhile the Norwegian classification society, DNV, has already issued an approval-in-principle to CSSC Jiangnan Shipbuilding shipyard, which would be a clear sign that we may see the first of this kind of ship being launched. Although the shipping industry is currently struggling with falling demand and too many conventionally-powered ships that it had built when demand surged in 2020, this kind of new container ship might be just the game changer it needs to meet today’s economic reality.
That said, although a lot about the KUN-24AP is not public information, we can glean some information about the molten salt reactor design that will be used, along with how this fits into the whole picture of nuclear marine propulsion.
Not New, Yet Different
The idea of nuclear marine propulsion was pretty much coined the moment nuclear reactors were conceived and built. Over the past decades, quite a few have been constructed, with some – like commercial shipping and passenger ships – being met with little success. Meanwhile, nuclear propulsion is literally the only way that a world power can project military might, as diesel-electric submarines and conventionally powered aircraft carriers lack the range and scale to be of much use.
The primary reason for this is the immense energy density of nuclear fuel, that depending on the reactor configuration can allow the vessel to forego refueling for years, decades, or even its entire service life. For US nuclear-powered aircraft carriers, the refueling is part of its mid-life (~20 years) shipyard period, where the entire reactor module is lifted out through a hole cut in the decks before a fresh module is put in. Because of this abundance of power there never is a need to ‘save fuel’, leaving the vessel free to ‘gun it’ in so far as the rest of the ship’s structures can take the strain.
Theoretically the same advantages could be applied to civilian merchant vessels like tankers, cargo and container ships. But today, only the Soviet-era Sevmorput is still in active duty as part of Rosatom’s Atomflot that also includes nuclear powered icebreakers. After having been launched in 1986, Sevmorput is currently scheduled to be decommissioned in 2024, after a lengthy career that is perhaps ironically mostly characterized by the fact that very few people today are even aware of its existence, despite making regular trips between various Russian harbors, including those on the Baltic Sea.
The KLT-40 nuclear reactor (135 MWth) in the Sevmorput is very similar to the basic reactor design that powers a US aircraft carrier like the USS Nimitz (2 times A4W reactor for 550 MWth). Both are pressurized water reactors (PWRs) not unlike the PWRs that make up most of the world’s commercial nuclear power stations, differing mostly in how enriched their uranium fuel is, as this determines the refueling cycle.
Here the KUN-24AP container ship would be a massive departure with its molten salt reactor. Despite this seemingly odd choice, there are a number of reasons for this, including the inherent safety of an MSR, the ability to refuel continuously without shutting down the reactor, and a high burn-up rate, which means very little waste to be filtered out of the molten salt fuel. The roots for the ship’s reactor would appear to be found in China’s TMSR-LF program, with the TMSR-LF1 reactor having received its operating permit earlier in 2023. This is a fast neutron breeder, meaning that it can breed U-233 from thorium (Th-232) via neutron capture, allowing it to primarily run on much cheaper thorium rather than uranium fuel.
The Easy And Hard Parts
Making a very large container ship is not the hard part, as the rapid increase in the number of New Panamax and larger container ships, like the ~24,000 TEU Evergreen A-class demonstrate. The main problem ultimately becomes propelling it through the water with any kind of momentum and control.
Having a direct drive shaft to a propeller requires that you have enough shaft power, which requires a power plant that can provide the necessary torque directly or via a gearbox. Options include using a big generator and electric propulsion, or to use boilers and steam turbines. Yet as great as boilers and steam turbines are for versatility and power, they are expensive to run and maintain, which is why the Evergreen G-series container ships have a 75,570 kW combustion engine, while the Kitty Hawk has 210 MW and the Nimitz has 194 MW of installed power, with the latter having enough steam from its two A4W reactors for 104 MW per pair of propellers, leaving a few hundred MW of electrical power for the ship’s systems.
This amount of power across four propellers allow these aircraft carriers to travel at 32 knots, while container ships typically travel between 15 to 25 knots, with the increased fuel usage from fast steaming forming a strong incentive to travel at slower speeds, 18-20 knots, when deadlines allow. Although fuel usage is also a concern for conventionally powered ships like the Kitty Hawk, the nuclear Nimitz has effectively unlimited fuel for 20-25 years and thus it can go anywhere as fast as the rest of the ship and its crew allows.
Got To Go Fast
Today’s shipping industry finds itself as mentioned earlier in a bind, even before recent events that caused both the Panama and Suez canals to be more or less off-limits and forcing cargo ships to fall back to early 19th century shipping routes around Africa and South America. With faster cargo ships traveling at or over 30 knots rather than about 20, the detour around Africa rather than via the Suez Canal could be massively shortened, providing significant more flexibility. If this offering also comes at no fuel cost penalty, you suddenly got the attention of every shipping company in the world, and this is where the KUN-24AP’s unveiling suddenly makes a lot of sense.
Naturally, there is a lot of concern when it comes to anything involving ‘nuclear power’. Yet many decades of nuclear propulsion have shown the biggest risk to be the resistance against nuclear marine propulsion, with a range of commercial vessels (Mutsu, Otto Hahn, Savannah) finding themselves decommissioned or converted to diesel propulsion not due to accidents, but rather due to harbors refusing access on ground of the propulsion, eventually leaving the Sevmorput as the sole survivor of this generation outside of vessels operated by the world’s naval forces. These same naval forces have left a number of sunken nuclear-powered submarines scattered on the ocean floor, incidentally with no ill effects.
Although there are still many details which we don’t know yet about the KUN-24AP and its power plant, the TMSR-LF-derived MSR is likely designed to be highly automated, with the adding of fresh thorium salts and filtering out of gaseous and solid waste products not requiring human intervention or monitoring. Since the usual staffing of container ships already features a number of engineering crew members who keep an eye on the combustion engine and the other systems, this arrangement is likely to be maintained, with an unknown amount of (re)training to work with the new propulsion system required.
With Samsung Heavy Industries, another heavy-shipping giant, already announcing its interest in 2021 for nuclear power plant technology based around a molten salt reactor, the day when container ships quietly float into harbors around the world with no exhaust gases might be sooner than we think, aided by a lot more acceptance from insurance companies and harbor operators than half a century ago.
(Top image: the proposed KUN-24AP container ship, courtesy of CSSC)
Good because a small handful of cargo ships outweigh the emissions of every single land vehicle on Earth combined. But they are going to have to have the steel to open up with chainguns on Somali boats approaching them (somehow I doubt the Chinese have any qualms with this)
What is the definition of “small handful”?
Probably over 10,000 ships (USA only), assuming my math is decent.
The graph above shows that 100 tons per day is a reasonable average, so, that gives us about 200,000 lbs, or 33,333 gallons per day, or 12,166,666 gallons per year. The average USA car burns 489 gallons per year, which means that a container ship uses as much fuel as about 25,000 cars. But, because there are over 250 million cars in the USA, it would still take over 10,000 container ships to offset that. (Some numbers were pulled from Google and may not be accurate)
There are tons of extra factors, such as ships having dirtier exhaust, or often running outside of the range on the graph, etc. This was just a rough estimation.
How many ships are there (USA only) that exist?
I thought bunker fuel was (literally) tons dirtier than an equivalent amount of gasoline or diesel?
I’d think that’s more due to bunker fuel burning with lots of soot, i.e. particulates, and sulfur emmission. It doesn’t help that there are way fewer mandates on sea than on land, and therefore companies tend to not filter much (if at all) of their emissions.
Modern truck diesels would be sooty too if it weren’t for mandatory particulate filters, and emit lots of sulfur dioxide (causing acid rain) if it weren’t for mandatory sulfur removal during fuel production. Regulation has come a long way in the past 50 years, at least on land.
Bunker oil is a heavy fuel oil (HFO) used by large ships because it is much less expensive than lighter and cleaner fuels. Its viscosity is similar to tar and it poses significant environmental risks. However, shippers pay a price with onboard settling tanks and centrifugal separators for purification. Alfalaval, Mitsubishi and Westfalia are some of the suppliers of this purification equipment. In addition to reducing carbon emissions, these purification systems can significantly improve engine life by removing some abrasive material from the HFO.
The cost savings are so large that most shippers will temporarily halt operation of a ship if its purification system has a breakdown. This is despite the fact that cleaner fuels are available. Over nite, worldwide service networks support these systems.
HFO is so viscous and dirty that it is banned as a fuel source for ships traveling in the Antarctic
https://www.youtube.com/watch?v=2HI_dsnKRtg
https://en.wikipedia.org/wiki/Heavy_fuel_oil
To be fair, today’s cargo ships are relatively efficient when it comes to moving those 25,000 cars (or whatever cargo) across the ocean. Improvements certainly could be made (including finding ways to ship less, of course), but from a grams of CO2 per tonne-km, it’s hard to beat a large container ship. Rail is probably better though getting stuff across an ocean would make that a challenging choice.
Maybe ammonia.
https://www.canarymedia.com/articles/sea-transport/the-race-is-on-to-build-the-worlds-first-ammonia-powered-ship
“Good because a small handful of cargo ships outweigh the emissions of every single land vehicle on Earth combined.”
Serriously doubt the “small handful” part. BTW, hurray for China. /s
China is building six times more new coal plants than other countries, report finds
March 2, 2023
https://www.npr.org/2023/03/02/1160441919/china-is-building-six-times-more-new-coal-plants-than-other-countries-report-fin
“Everybody else is moving away from coal and China seems to be stepping on the gas,” she says. “We saw that China has six times as much plants starting construction as the rest of the world combined.”
Winston Sterzel?
On the one hand something really has to be done about marine emissions – living next to a port, I can taste when a few large ships are in.
On the other hand, I’m not convinced anyone needs cheap imported tat enough for a nuclear container ship to be the answer.
This is likely just a concept. China has far too many more important issues to focus on than a cargo ship with limited harbor access. Not to mention that a ship of this size is not going to be able to use the two canals mentioned. You run into many logistical issues even after you have it built and running.
This feels like Soviet propaganda. We are so forward thinking! We put a reactor in a shipping contain. Totally new, never been done before. Pay no mind to the practical implementation it has. This is a wonder of the technological world.
Assuming the Somali pirates can catch up to them. Even then, a good pump and water nozzle should clean up nicely.
The problem with trying to stop people boarding with a water hose is that a machine gun soon puts off the person with the hose plus for every port the ship calls into you need a firearm license for each person that uses them.
With nuclear reactor You have a lot of steam, easy to dump down the ladder :)
“the detour around Africa rather than via the Suez Canal could be massively shortened”
It’s not a “detour” if a nuclear powered cargo ship cannot even sail in certain waters (i.e., Suez Canal area, due to boomboom)
They were referring to when the canal was closed and therefore forced all ships to make the expensive detour.
Boomboom isn’t really a concern, the issue is the kind of environmental disaster that could happen.
Well it may be a concern in some European countries (especially Germany) with a strong Anti-Nuclear movement. And quite some more countries are in some form of trade war with China and may deny these ships access to their harbors/territorial waters for “safety concerns”. This may in the end significantly limit the use cases for nuclear ships made in China.
Well this is a braindead comment. There is no “boomboom” because it’s Thorium-based molten salt reactor. It doesn’t make anything used in nuclear weapons.
I thought boomboom referred to the Houthi marauders.
Yeah, a bit vague.
yesyesyes I did mean boomboom of unfriendly people who can reach out to nearby boats.
I wouldn’t be too down on non-nuclear submarines and carriers – both are still very capable and can operate at vast distances from base, and as the range of a carrier is dictated by the range of the shortest ranged escort vessel anyway… So while nuclear carriers can go a long way on its own it will never actually do so, and the support vessels are not nuclear powered (largely anyway).
And nuclear vessels have a larger minimum size – big is great out in the deep waters, but makes resupply and operating near the coast much harder. Which is a problem that may bite this cargo ship too – if its too big to dock in most places you have to hope there is enough trade between the few ports that are deep enough to take it – (which is already true for many of the larger cargo ships from my understanding, so bigger still may well be too far).
yep, I read “Meanwhile, nuclear propulsion is literally the only way that a world power can project military might, as diesel-electric submarines and conventionally powered aircraft carriers lack the range and scale to be of much use.” and laughed.
nuclear subs are a special use case – and very useful for that – but non nuclear subs are both much cheaper and fine for many many things…
Indeed, and at least in training exercises more than a few allied navy and their often diesel electric sub have humiliated a US fleet by sinking the carrier.
Not really my area of expertise but pretty sure it has reportedly happened a few times and not just been the UK Royal Navy (which would for me be local news), but the Swedes and French I think the Aussies too have sneeked in, though some these events are rather old now and some may have been nuclear subs – as I said not really something I care that much about.
And on the front of projecting power there have been so many aircraft carrier that are/where not nuclear and have projected power a very long way from home and try telling the German Uboats of WWII they were short range… Can’t stay submerged forever, but not like they don’t have legs.
“Indeed, and at least in training exercises more than a few allied navy and their often diesel electric sub have humiliated a US fleet by sinking the carrier.”
No, that has literally never happened. Some allied navies have “sank” a US carrier when the US desugned the exercise to be so heavily weighed in the submarines favour that it would be damn near impossible for it to fail to “sink” the carrier. Nobody was embarrassed by the inevitable outcome; it was good training for everyone involved.
Are you saying the swedish submarine rented by the us navy didnt manage to “sink” the carrier in the wargame scenario it participated in ? From what i recall, the yanks could even find the thing until the swedes popped up to the surface, 700 yards from the carrier.
A suitable thorium reactor will fit into any present day panamex or suezmex sized container ship without issue.
“And nuclear vessels have a larger minimum size – big is great out in the deep waters”
“Big” doesn’t necessarily mean “deep draft” or especially deep draft. They didn’t tell us what it would be, but one can even imagine a surface effects craft actually able to come up on land, no harbor required, maybe just a good mudflat or marsh.
>“Big” doesn’t necessarily mean “deep draft”
True, but the two do have a correlation. But even in the case where your draft is unchanged bigger doesn’t always work – dock infrastructure is only so big, the inlet and turns you must take to manoeuvrer while in closer to the coast become harder or even impossible.
If you want to build a nuclear powered landing craft you probably could. But at the same time being bigger there with the usual military context of landing craft isn’t a great idea, putting too many eggs in that one basket while also limiting just how many beaches you could land at.
Even bigger? Are we talking exceeding PanMax or SuezMax? And what about countries that will probably block port privileges because of the nuclear reactor?
Given the unmitigated environmental disaster which is the current container ship system, this has to be a good thing. But what’s really interesting is that it will use a thorium reactor. I’ve heard the Chinese were investing heavily in thorium but hadn’t realised that got beyond the prototype stage. Theoretically thorium is cheaper and safer and generally less polluting than uranium reactors, and is ideal for this use case. I wonder if they’ve actually managed to achieve this in practice?
A not-so-incidental side effect, by the way, would be a line of commercialised modular small thorium reactors for general-purpose electricity generation.
Which could make electric cars work, and or completely overhaul the ‘grid”. Probably wind up having ‘red power’ only for charting cars like we have ‘red diesel’ only for farming.
If they’re going to make this thing larger than Panamax then why not make it an ice-breaking cargo ship? It would have the power to go through the Northwest Passage, size would not be problem and it would be quicker to get from China to Europe or the east coast of America.
Probably because the Northwest Passage is only usable during the summer, even for ice breakers. The length of time that it remains usable has been growing over the last couple decades, but it doesn’t seem prudent to design your first nuclear cargo ship around a route which is problematic at the best of times.
Great thing, especially them using Thorium.
I’m just a bit concerned that it’s designed, built and maintained in China. They don’t have the best of track records for keeping things working and cleaning up after themselves.
I wouldn’t want a Chinese designed and built floating reactor anywhere near our coasts. The CCP is corrupt and will cut any corners that exist. Look into the collapsed “tofu-dreg” constructed buildings, unless the CCP and their shills have successfully scrubbed the evidence clean from the internet.
Nuclear power for Chinese ship is good for planet, nuclear power for mains in USA is bad…why?
When you find out please tell the rest of us.
Beats me. The logic applied by some members of our society is indeed very confusing, convoluted and contradictory.
You got me… Logic escapes me too. Nuclear is good ‘everywhere’. The greenies should be more than happy to promote nuclear energy. Meanwhile keep the coal/gas flowing until we finally transition to the clean energy :) .
That.
Without cheap reliable energy there’s no civilization to be worth its name. Without cheap reliable energy the transition to cheap reliable green energy will be rather painful. Few politicos seem to understand this.
I am sorry, i really don’t like this and i am NOT talking stupid politics. How safe is this thing? We had already 2 meltdowns (remember your history lessons) of nuclear reactors with catastrophic consequences. And i am really afraid this thing – if it is the first of its kind – will have some problems that have to be sort out, but we are talking a F*** NUCLEAR REACTOR, not some random device (that when it blows up might be a *local* desaster but “only” a *local* one). Also i am really afraid some nasty people will get on this thing, mess with some buttons and/or put some explosives somewhere and/or other sabotage. No, please, don’t. Yes CO2 is a big concern and ships also blow other nasty stuff into the air, but going nuclear? Yeah…
Why can’t we have nice things?
Cause they clash with the drapes.
LOL!
(Thanks, that laugh helped clear some lung passages)
A molten salt reactor is incapable of melting down – the nuclear reaction does not produce enough heat on its own to maintain the salt in a molten state. If there’s ever an issue, an emergency frost plug can have the power cut to it, allowing it to melt and drain the system out into a containment vessel where it will solidify and act to moderate and dampen the nuclear reaction. Even if that fails, the molten salt will solidify in place and won’t go critical.
This ^
There is no secure up/down on a ship …
Please educate us about the catastrophies that occurred. Because last time I checked, the number of people killed by the nuclear industry was dwarved by the number killed in fossil fuel industry, and that’s without counting climate change.
As if the number of fatalities were the only metric by which to measure the severity of an accident.
More generally, while it may be possible to design a nuclear reactor that is “safe”, the project to staff them with commensurately “safe” builders and operators has been stuck at Human Being rev 1.0 for a looong time.
Negative health effects among workers around nuclear reactors are also way lower than among those working around fossil fuel reactors.
Sorry – it is not the first of its kind.
USDOE built a TMSR at the lab in Tennessee. I suggest you do a little research on “thorium molten salt reactor” before extrapolating whatever you understand about uranium-water reactors.
Note that US Naval reactors have used lIquid sodium in the primary coolant loop for a very long time.
Naval reactors systems are not refueled but are removed as sealed units and reprocessed a special facility.
One obvious failure mode is that the highly radioactive and water soluble irradiated thorium salts get dumped/leak near the coast and wipe out an entire fishing ecosystem, perhaps affecting 20M people. Given China’s reliance on offshore fisheries this seems like a pretty poor choice for them.
They’ll just make sure the accidental leak happens along some Western country’s coast
On the upside, if things go tits up with the reactor, all you have to do is pull the plug and sink the damned thing to keep it out of sight and mind.
Quote: “These same naval forces have left a number of sunken nuclear-powered submarines scattered on the ocean floor, incidentally with no ill effects.”
Response: Go breathe asbestos dust all day for a week. Test your health a month after that. You are very likely to find no impact. Does that mean that asbestos is safe?
A fire on a nuclear submarine under the ocean is a tragedy for the crew and people close to them, a fire on a nuclear containership in a harbor could be a tragedy for everyone.
Molten salt reactor cannot melt down, it already is during operation. The salts used are nonflammable and nonvolatile. The volatile fission products can be removed from the salt loop online during operation, keeping the inventory low.
It’s not a pressurized water reactor that can fart mightily if the coolant loop is broken.
But nukular baaaad.
It’s main safety feature is meltdown, if you just let it sit in the reactor without cooling it the salt will become hot enough to become volatile. Dropping down into containment to spread out and cool quickly will be harder when down can become up.
Assuming moderation fails obviously.
The plug method is nice for a static application, but reaching a high level of confidence that you don’t have a pool of salt reaching a very high equilibrium temperature after capsizing will be a lot harder. On a ship you will be forced to put more confidence in active safety.
Its never too early to panic.
Especially when you have a lot of Chicken Little’s running around out there. :rolleyes:
Why do we not using air ships like the one in the disneys series TaleSpin?
I want to be an air pirate, Arrrrrrr!
Ah yes now i remember the Hindenburg, there was something, safety standards and so… :-)
Ships like that definitely need one of those guns that shoot missiles that are too close out of the air.
It’s purely defensive so there’s little to complain about.
Of course now thanks to the damn ukrainians making it a thing we now also need an anti-‘water-drone’ device to compliment that, although that can get tricky to ID as hostile or just a small boat sailing along.
Maybe just a container.
https://youtu.be/kyH47LHgeNc
Where will China dump the “cleaner” nuclear waste? And who will watch over it for the required 10,000 years?
This is not the strawman you’re looking for. As mentioned in the article already, an MSR is capable of very high burn-up due to the fuel being mixed in with the coolant, meaning that it can use most of the transuranics and minor actinides that normally are stored with ‘spent fuel’ are instead fissioned. This means that an MSR can not only run on very little fresh fuel, but also produces a negligible amount of radioactive isotopes that it cannot breed into more fuel, such as radioactive xenon gas. This is all however very short-lived, on the order of minutes to months before it drops below background radiation levels.
Darn good answer Maya!
(Android substituted “darn” for what I wanted to write)
Does Android _really_ censor “damn” to “darn”? That would be fucking stupid.
The biggest problem with this design is the use of molten salts. At those temperatures most metals will react with the salts. Doesnt bode well for long term applications. If this was viable, we would already have molten salt reactors in commercial production.
Anything we do to try and save the planet, a volcanic eruption puts us back a few hundred years.
EV’s are a tax pure and simple.
AI should be solving self-charging not self-driving.
I am a manual wheelchair user disabled driver and electric are just not compatible with my life.
I have modified a lot in my life.
Russia has a ‘graveyard’ of decaying, nuclear powered icebreakers. What happens to thousand of decaying, radioactive containerships. Russian has frequently been caught, dumping them in the sea of Japan.
Similarly with the pile of unwanted electric vehicles.
What happens when they are no longer useful?
I am not qualified in terms of either technical or economic knowledge, to give educated statements, but…
Why don’t we start doing things that WORK**?
** I mean, work, not only for a few years or decades, but ( as a technology) sustainable?
Obvioulsy we (humanity) found out we cannot continue using fossile fuels forever (of course we can for another 150 years, but already now it has stopped feeling cozy, hasn’t it ?).
And we are talking about commercial use.
Commercial use is always tied to cost.Even now the (true) cost of nuclear power is much higher (and only doable with high subsidies) than using renewables. Renewables may at the moment be no choice for marine vessels (except you produce green hydrogen on land and use that). Think about the immediate cost of commercial nuclear powered vessels. Safety protocols (would it really make you feel better knowing that the chinese won’t care as much?). Maintainance. I am sure the IAEA would kick in.
Don’t compare that to military use, as there: 1) cost is usually not a major factor, 2) possible radiation exposure is more easily tended to be defined as soldiers “job risk”
So i think for that reason only it will not happen.
I think it has been in the mid 70s we internationally stopped dumping nuclear waste into the ocean (officially).
In that context,the risks of the vessel *in use* have been discussed here.
Still the problem with nuclear waste remains.
To my knowledge worldwide NO safe solution for storing nuclear waste (for 100000s of years) has been found. There is NO company, NO government that can guarantee keeping them safe even only for centuries.
Show me one company that exists since millenia?
Has anyone ever calculated the costs of keeping something safe for 100000 years?
The germans have a storage place (Gorleben, evaluation site, cost til now 1.6 billion eur) where they encased barrels with weak radioactive waste molten into glass blocks, only to find out that after only 50 years water leaking in (into the forever dry salt stock) had corroded the steel barrels
Do you remember, that after the ussr breakdown, some russian long range missile bunkers were found to be guarded by 2 (!) soldiers stationed in a wooden hut?
Do you remember that “the dome” built over the remains of the chernobyl reactor (only to be afforded with large international financial help) will only last for about 100 years?
Are you aware that the japanese gvt. has decided to dump the contaminated fukushima waters into the ocean for “cost reasons”?
Three mile island (meltdown 1979)
current status:Today, the process of decommissioning Three Mile Island is still underway and according to the NRC, will be finished in 2079.
So… it feels for me fission is a bad loan… to our future.
So on the long run , can we afford fossile?
Can we afford fission?
I hope we will be able to afford fusion in the future.
But for now, lets use what we have. water. wind (container sailing ships?). sun.