Cyril R wrote:
E Ireland wrote:If fuel costs for the reactor are essentially zero the only thing that matters is capital cost.
At which point they will want to go as fast as possible so they can make more trips.
IN other words, 35 knots.
Reactor systems are much more expensive than combustion engines, so the higher power needed for high speed does cost you in terms of capital cost... on the other hand there is the economy of scale which is strong with reactors especially upgrading from a tiny to a small reactor size.
Whatever size is installed though, like you say they will likely run at full throttle all the time with cheap nuclear fuel, plus a nuclear reactor is easier to operate in a constant power mode.
ICE engines are cheap, but the fuel isn't. And we're assuming oil won't jump to US$ 150-200.
BTW, very large ships aren't built to be able to go that fast, there are structural issues. A ship that only have enough HP to go at 21kts, can't go 35kts without some fatigue issues. Those ships have weight and balance issues similar to a very large aircraft. And if you go very fast, then you'd stay 80% of the time at port (diminishing returns). For instance, I mentioned ore carying ships because my dad was a port manager and I got to visit one of those many times (it was the largest ore/gain ship in the world, Berg Stahl, that was 1988, even in a slow 13kts cruise it spent 15 days travelling each way for 5 days loading or unloading, so 2/3 at sea for 1/3 at port, you double the speed and you're only increasing it's productivity by 1/3, so doubling again makes no sense, but for a ship that did Brazil to China or Japan it would make more sense, since it's a journey 4x longer, they are way too big for the Panama Canal).
All of this assumes current LWR costs. Forget about civilian LWR ships. LFTRs need to cost half as much, by standardizing on a single size if at all possible (say 500MWt / 250MWe, maybe a smaller 100MWt / 50MWe, but it would be better if it could be the same reactor with just less nuclear fuel or some very minor changes), and concentrating on economies of scale and factory production. We fall to the trap of trying to optimize the technical performance of the reactor at the expense of standardization.
Without a scale of at least 100 reactors per year, nuclear will never replace huge ICE engines. Has to be the exact same reactor that would be used on land. Ships sail at least 50% of the time, day and night, so their fuel costs are very high that with an expensive enough oil it would make sense to go nuclear.
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