Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Unstable in what way ? Uranium is a naturally occuring element in the Earth's crust. We mine it to make our bombs. If enough uranium was concentrated through some natural process, say deposited by water, and moderated by the same water, you can get a reaction and a temperature rise. Google the Oklo natural reactor. <br />Posted by mee_n_mac</DIV><br /><br />Thanks for the link, mee-n-mac. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>