<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><span style="font-family:arial,sans-serif">On Sat, Sep 10, 2016 at 9:18 PM, spike </span><span dir="ltr" style="font-family:arial,sans-serif"><<a href="mailto:spike66@att.net" target="_blank">spike66@att.net</a>></span><span style="font-family:arial,sans-serif"> wrote:</span><br></div><div class="gmail_extra"><div class="gmail_quote"><br></div><div class="gmail_quote"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font size="4">​I think Feynman was more worried about U-235 than Plutonium when he was sent out to Oak Ridge. The huge gas diffusion plant out there had separated appreciable amounts of U-235 from the much more common U-238, enough that it could be very dangerous if you didn't know how to handle it. The big breeder reactors that made Plutonium were in the state of Washington near the town of ​Hanford.  </font></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font size="4"><br></font></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font size="4">Feynman wrote a article about his wartime bomb making experiences that I found very interesting and entertaining. </font></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><a href="http://calteches.library.caltech.edu/34/3/FeynmanLosAlamos.htm">http://calteches.library.caltech.edu/34/3/FeynmanLosAlamos.htm</a><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font size="4">John K Clark</font></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div lang="EN-US"><div><p class="MsoNormal"><br></p></div></div></blockquote></div></div></div>