Unlike most other sources of low-carbon energy, nuclear power stations aren’t constrained by geology (as geothermal plants are), geography and meteorology (like hydro), wind, solar or tidal conditions. Since nuclear is a thermal power technology (i.e. like coal and gas it works by generating heat) it requires a source of cooling, so nuclear power plants are often built near the sea or rivers. However they don’t have to be and can use cooling towers.
Large nuclear power stations (producing Gigawatts of power) are usually sited in sparsely populated areas to ease evacuation in case of a major accident. However pool type reactors have been proposed for district heating in China and may be under consideration in Finland. These, like the research and teaching reactors installed at some major universities, are inherently safe and can be sited in heavily populated areas.
Russia has even built floating reactors, and China is possibly following suit. The Russian reactor is based on a design used in its icebreakers which have long used nuclear power for propulsion and the ships’ electrical systems (as of course have submarines and aircraft carriers of the Russian, US, British, Chinese and other navies since as far back as the 1950s).
The size, and particularly the need for skilled operators, restricts where current generation nuclear power plants can be used. Several designs of reactor with smaller power outputs, some with simplified and/or remotely operated controls, have been and are being developed to serve small remote communities, for example, but there are few if any designs already licensed and ready to build.