Originally Posted by Bennylava
Question: Why were the reactors by the sea, in a land where the word "Tsunami" comes from?
Because it's an excellent way to dump the heat generated by the plant. Under normal operation, water is first heated to be 400+C steam by the reactor before passing through a turbine. As it passes through the turbine it expands and cools back to 100-150C (still steam). This water must be cooled further before re-entering the reactor (to <50C), and so there is still a large amount of heat to be dissipated. This is usually done with a cooling tower, the iconic symbol of nuclear power. These are expensive to build are have several drawbacks. If you position the plant near a large body of water such as an ocean, lake or river you can simply dump the heat into that body of water, which is much more reliable than a cooling tower, while also being cheaper.