Well, technically speaking, any onsen is nuclear heated, given that geothermal energy it uses is produced by nuclear decay from radioactive isotopes deep inside the planet...
Well, technically speaking, any onsen is nuclear heated, given that geothermal energy it uses is produced by nuclear decay from radioactive isotopes deep inside the planet...
And even more technically speaking, Okuu doesn't really do fission, she is mostly Fusion operated so it would be Solar-powered.