William Thiel,
jst to complete the matter. DU (U-238) radiates as we both said earlier alpha (helium nuclei) radiation, I'm not sure about the beta (electrons and sometimes positrons) but you checked so you're probably right according to my boss the really dangerous radiation is coming from natural fission and radiates neutrons but this happens around 70 times a secong for one kilo(!) of U-238.
Thought you might like to know.
Wouter