It's so funny, I just heard Brady Haran and his buddy Tim talking on The Unmade Podcast about swimming in the cooling pond of a coal powerplant near Adelaide where they are from.  Similarly, (?) we have a (now decommissioned) nuclear power plant here south of Sacramento California which has (had) as part of its cooling system a small lake which was part of a recreation area and people (including myself as a child) swam, boated, fished, etc. in that lake.  Many still do.  Look up Rancho Seco Nuclear plant.