Reactor h2o itself does not carry radiation, but any extra molecules in tend to do it, thats the reason why the water is as clean you can get, over-distilled. This by itself means that it is not potable (btw for disposal to environment it gets re-salinated), so they told the story of professor drinking it must be an urban myth. It is bad even for skin expose (swimming in it), but hopefully that worker got just a few seconds expose and is well. Source: training trip in a nuclear center.