You'd think an eternal steam engine would be slightly inferior to a vaguely nuclear standard power generator. At least in power output, if not in longevity.
Yeah but a self sustaining steam engine translates into mechanical force better/faster, and looks cooler, and doesnt irradiate the crap out of you when someone shoots the reactor, and is environmentally friendly, and has lots of shiny pipes, and can use steam pressure to fire harpoons, and is awesome, and is cheaper, and can propel you in a vacuum, and is retro, and is train-like, and im gonna stop now...
I think the eternal steam engine when considered in a power plant scenario might be able to pump out more juice then its nuclear counterpart at the same scale, i mean steam engines dont need all the safety devices, decontamination rooms, computer consoles, radiation shielding or bigass concrete chimneys that are integral to safe operation and maintenance of a nuclear reactor of that magnitude.
... You are aware that nuclear power plants are basically giant steam engines, yes? No, your infinite power source won't convert energy more efficiently or quickly. Indeed, it would probably be
less efficient, if not slower, because you'd be using what would amount to a boiling water reactor setup with the nuclear core replaced with that artefact. And good luck trying to make a nuclear reactor spit radiation at you by shooting it. Hint: You won't be able to breach the reactor at all. And even if you did, you'd have a bigger issue with being broiled alive by all of the flash-boiling, extremely high temperature and high pressure coolant.
And none of those things make any difference to power output. And those 'bigass concrete chimneys' are needed to cool and recondense used steam. Something every steam engine has to deal with, just a different solution.