Where will the priming energy to sustain the plasma come from, if an emergency restart at sea is needed?
Launch HN: Maritime Fusion (YC W25) – Fusion Reactors for Ships
191–200 of 267 posts
Re: Launch HN: Maritime Fusion (YC W25) – Fusion Reactors for Ships
#192> One common question is, why not fission? Fission works technically, but not practically. Small Modular Reactors (SMRs) could power ships, but licensing fission reactors on land is already brutally hard and expensive—doing it for vessels moving between international ports with enriched uranium is nearly impossible What makes you think that licensing a fusion reactor will be easier? Safely handling tritium is fantast…
Safely handling tritium is fantastically more complicated that the fuel of a fission power plant - I disagree with this, especially when considering the infinitely long HLW with fission fuel. Handling Tritium isn't easy but it's much more manageable. Tritium breeding: we will have a FLiBe blanket and breed tritium, but we won't be processing and pulling out the Tritium on board, that will happen on land, so at port y…
> infinitely long HLW with fission fuel
You don't have to process high level wastes on your ship, but you do with tritium. Even if you don't plant to extract the tritium from the blanket modules, you do need to recycle the unburnt fuel (the burn-up fraction is at best a few percent).
Tritium is radioactive hydrogen: it's a gas that explodes in air at low concetrations, it reacts with organic compunds, it has high mobility in pretty much any material, by decaying it produces Helium bubbles that can embrittle metals, its β radiation crack glasses etc.
Re: Launch HN: Maritime Fusion (YC W25) – Fusion Reactors for Ships
#193Where will the priming energy to sustain the plasma come from, if an emergency restart at sea is needed?
They need a backup powerplant for propulsion anyway, there's a million things that can go wrong with the reactor and you can't repair it a thousand miles away from land.
And maritime diesels have a lot of power. 50 MW is not unusual. Add a couple of batteries/fly wheels/super capacitors, and you easily have enough to start a fusion reactor.
Re: Launch HN: Maritime Fusion (YC W25) – Fusion Reactors for Ships
#194I had a startup in the bunker fuel market (BunkerEx - acquired a few years ago) - if you need any on the ground help let me know!
Re: Launch HN: Maritime Fusion (YC W25) – Fusion Reactors for Ships
#195Earlier quoted context omitted.
There is at least the possibility that fusion power could eventually be viable for privately owned civilian merchant ships. Fission power is a non-starter in that market due to concerns (valid or not) over security, terrorism, proliferation, and meltdowns. Even if someone builds a new fission powered merchant ship it would be useless because many nations wouldn't allow it to enter their ports. Military fission power…
Aren't the products of fusion equally radioactive? I get that we all have the idea of helium being the main product, but don't you get a lot of tritium out of the process? It's not quite proliferation, but it's not non-radioactive either.
Yes, tritium is radioactive but it has to be recycled and reused to continuously fuel the reactor. Every part of a fusion reactor is designed to minimise the retention of tritium, the actual radioactive waste will be materials activated by neutron radiation (neutrons are captured by nuclei, transmute the element into a radioactive one which then decays to a stable isotope emitting more radiation).
A small fusion reactor, being a powerful neutron source, will be a great risk for proliferation. It should be able to breed plutonium for nuclear weapons as much as it can breed tritium.
Re: Launch HN: Maritime Fusion (YC W25) – Fusion Reactors for Ships
#196Don't understand how that could have somehow been vetted by a YC committee. I mean I'm all in for fusion power, but so far it remains in the state of utterly edge-case research project into which governments all over the world have been pouring insane amounts of money in the hope for the holly grail of energy. And you are spawning a private company that is discussing the nitty-gritty details of applying that non-existent technology to a niche market?
I mean would people invest into a startup applying quantum computing to wearable devices? And that latter idea is actually way more down to earth.
Re: Launch HN: Maritime Fusion (YC W25) – Fusion Reactors for Ships
#197Earlier quoted context omitted.
There is something very compelling about a fusion-powered ship also having sails.
Let's be realistic, it would have a diesel engine as a plan B. But if you like sails: my pet hypothetical technology is wind-driven hydrogen tankers (or tankers for some other e-fuel derived from hydrogen) that sail out empty, then cruise around wherever there is plenty of wind. They'd have a turbine/generator setup driven by the water passing by and use the energy harvested there for filling the tank. Cruise around…
Interesting concept. Let's run the numbers...
The largest Q-Max-class gas tanker is 345 meters long [1]. Let's say you manage to fit 3 giant Siemens wind turbines on it, with 100m long blades [2]. It's a bit cramped but let's say you have extenders on the side to make room for all 3 of them. And also let's say you found a way to prevent the ship from tipping over when the wind is strong. By deploying floaters on the side or whatever. Not unsurmountable.
Each of those wind turbine has a rated power of 14.7 MW [2]. Let's say that you found a place where the wind blows super strong (but not too strong) and steady all the time. It's possible, since you are a mobile ship, after all. Let's say that you have a way for the ship to keep in the same place despite the strong and steady wind pushing you constantly. Using engines is going to lower your efficiency, so let's say we found another way.
So, now your ship is generating 45MW constantly. According to ChatGPT, this is 32 kg of hydrogen per second, taking hydrolysis losses into account.
Tanker capacity is 18 620 000 kg of liquid hydrogen. It will take 581 000 seconds to fill up. 9697 minutes, 161 hours, or 6.7 days. Much shorter than I thought... Did I miss something?
[1] https://en.wikipedia.org/wiki/Q-Max [2] https://www.offshorewind.biz/2024/04/22/first-siemens-gamesa...
Re: Launch HN: Maritime Fusion (YC W25) – Fusion Reactors for Ships
#198Don't understand how that could have somehow been vetted by a YC committee. I mean I'm all in for fusion power, but so far it remains in the state of utterly edge-case research project into which governments all over the world have been pouring insane amounts of money in the hope for the holly grail of energy. And you are spawning a private company that is discussing the nitty-gritty details of applying that non-exis…
Helion Energy (https://news.ycombinator.com/item?id=8178450) has been going 11 years and building prototypes and raising many millions by saying power is 5 years away or so and not publishing any results. So I guess that model works sort of.
Currently "Helion claims it will build the world’s first nuclear fusion power plant by 2028 and has already secured a purchase agreement from Microsoft." but Sabine is sceptical (https://youtu.be/YxuPkDOuiM4)
Re: Launch HN: Maritime Fusion (YC W25) – Fusion Reactors for Ships
#199Earlier quoted context omitted.
There is something very compelling about a fusion-powered ship also having sails.
Let's be realistic, it would have a diesel engine as a plan B. But if you like sails: my pet hypothetical technology is wind-driven hydrogen tankers (or tankers for some other e-fuel derived from hydrogen) that sail out empty, then cruise around wherever there is plenty of wind. They'd have a turbine/generator setup driven by the water passing by and use the energy harvested there for filling the tank. Cruise around…
Or bunker oil.
But yes, fuel-based powerplant, likely as part of a hybrid drive running electric motors powering propellers themselves.
Marine propulsion is already pretty optimised for efficiency (turn on engine, set to cruise power, maintain for 14 days, little acceleration, starts, stops, and/or hills), so a hybrid setup would work pretty effectively.
The far greater challenges are Q>1 and reliable fusion within a ship's structure.
Re: Launch HN: Maritime Fusion (YC W25) – Fusion Reactors for Ships
#200Earlier quoted context omitted.
> I'd wager you'll end up pivoting to SMRs. They exist today. who is selling ~zero maintenance, mass-produced SMRs today?
How is that an argument to avoid SMRs if magical thinking about fusion reactors is allowed?
all my other comments on this post are about how fusion doesn't exist and YC funding a Fusion Boating Company before anyone has ever generated any net electricty with fusion is deeply stupid.
SMR can be stupid and not exist too!