It depends on the length of time you care about. Nuclea […]
It depends on the length of time you care about.
Nuclear submarines already do this. Since they have a large supply of electricity, they can use electrolysis to break water molecules back into hydrogen and oxygen gas. Thefilter materials resulting oxygen can then be used to oxygenate the air in the submarine. That part of the process can continue essentially as long as the nuclear reactor has fuel to power the electrolysis.
That's not the only thing you need to do to maintain breathable air though. You also need to remove carbon dioxide and moisture from the air. Carbon dioxide is usually removed with what are called "scrubbers". The air is run through a "filter" that contains some material (soda lime is common, but others would work as well) that reacts with carbon dioxide, and chemically binds it to the material in the filter. This can't continue indefinitely though--eventually you need fresh filter material.
Although they're (at least arguably) a little less critical in the short term, variousAquaculture filter Bag Manufacturers other filters are used to remove other toxic chemicals (carbon monoxide) from the air as well.
Moisture can be removed with a normal dehumidifier (again, there are other possibilities, but that's probably the most obvious one).
Bottom line: at least if we assume power is unlimited, getting oxygen is probably the single easiest part of the job, and the one that's most amenable to continuing essentially indefinitely.