Hey all, First off, am I correct in saying (generally) that Deuterium slows down neutrons? That's why nuclear reactors use it because its easier to catch neutrons that are going slower. ?? Does this apply to all neutrons? Example, lets say I drank a nice tall glass of delicious Heavy Water :). When the Deuterium interacts with whatever it comes in contact with in my body, will it slow down the neutrons of it? Can someone explain to me how deuterium does slow down neutrons? Thanks everyone.