[jdurg]

I was just looking through the table Mitch put up under the 'Miscellaneous' Nuclear link, and I was kind of shocked by how many so called stable elements have a large proportion of radioactive isotopes.  Re-187 is 62.6% of all naturally occuring Rhenium, and is a radioactive isotope with a half-life of 5.0x10¹⁰ years.  Indium, however, is 95.7% In-115 which is radioactive!  It's got a half-life of 4.4x10¹⁴ years though.  I did some calculations, and that comes out to an activity level of around 0.36 Bq per gram of pure Indium metal.  I don't know if there is anything out there that can even detect that.  This is the type of data that I would love to show people and watch their reaction when they see that certain things which aren't thought of as radioactive actually are.  Then they can realize that just because something is radioactive doesn't mean that it's dangerous.

[Donaldson Tan]

everyday, we are bombarded by neutrinos and other sub-atomic particles from outer space yet we are still alive and obviously not showing any signs and symptons of radioactivity poisoning. let alone exposure to elements with negligible radioactivity. it's interesting to note that U-238 has a half life of 4500 million years, so you can imagine the low radioactivity level it exhibits, yet it's potential source of so much nuclear energy when we convert it to plutonium.

somehow, this topic reminds me of the significant quantities (SQ) stipulated by the international agency for atomic energy. the SQ for plutonium is 8kg, yet the american used 6kg of plutonium to bomb Nagasaki during WW2. LOL. 8kg is too high to be the minimum SQ.