Short answer, yes. Longer and more precise answer is yes, but it's designed to go outside on the top. Mounting a 240mm rad inside a HAF912 usually requires a bit of...shifting as seen here http://www.legitreviews.com/coolit-systems-eco-a-l-c-24...
Your best bet would be to mount externally on top of the case, unless you really can't or don't want to. Here's a popular video showing how a guy mounted a 240mm rad to his HAF912, so hopefully that should help you decide what to do with yours.
http://www.youtube.com/watch?v=Qf5YiSdxzgs Good luck