After reading this post I tried to make one myself, got one going at 625eu/t. I'm using redpower/buildcraft tubing for maximum bucket efficiency. It's running for a while now without fail, pretty cool tbh.
Some screenshots:
http://imageshack.us/photo/my-images/573/reactorlayout.png/
http://imageshack.us/photo/my-images/707/20111025000445.png/
Edit: On a quick sidenote if you want to stop and restart the reactor you're going to have to build up to the maximum amount of uranium cells you see in the screenshot else it'll go super critical really fast.