Underway said:The air issue is more about fire then it is about operations. A nuke boat has oodles of power to create O2 though electrolysis. A diesel sub usually doesn't create O2, it either stores it (LOx) or scrubs CO2 instead.
AIP usually needs a big amount of stored LOx (liquid oxygen), either for the stirling engine or for the fuel cells, so that oxygen needed for the crew to breath for 2-3 weeks is only a small fraction of the stored LOx (quite below 5%). Replenish oxygen to the boat in case of fire should not be a problem.
However AFAIK, in order to crack the ice cap and emerge in the Arctic, two features are needed: buoyancy and strengthened hull (and sail, rudder, hydroplanes, sensors, etc). So the options would lead for something about 3,000 tons or above.
This year dutchs are to select their future subs among A26, Type 212 or a French Barracuda variant. Japan is retiring from Stirling technology but it has shown up as a robust technology. Unfortunately it seems too late to join the Netherlands and work together to develop and build a common boat.