Ilya caught me on this one:

>>Yucca Mountain is for disposal of high level nuclear waste
>>(fuel rods) which can have a half-life of thousands of
>>years. The vast bulk of nuclear waste is medium and low
>>level waste which has a typical half life of 50 years.
>
>Sorry, no. High-level waste is the one with short
>half-lives. Exactly because it decays rapidly it radiates
>very intensely, and thus is more dangerous. Spent fuel
>rods are a mix of both high- and low-level waste. After 50
>years or so they should be classified as a low-level waste,
>since the really dangerous stuff will have burned off by
>then. (The REALLY dangerous stuff, like Iodine-131, has
>half-life measured in days. Those can actually kill
>you if you so much as approach an unshielded rod. But
>within a year they are gone.)

I wish I could arrange for Ilya to proof read these posts of mine before I end up parading my stupidity. Yes, of course the high level nuclear wastes have short half lives. Yucca mountain is for storing nuclear waste containing a mix of isotopes including waste with long half lives as is the case with fuel rods. High level waste has short half life isotopes. Standard procedure with old fuel rods is to store them in a "swimming pool" until the high level waste has cooled and then relocate them for permanent disposal. Apologies about the error.

Gary