Wayne wrote:
>
> If fusion yeilds waste products that only have a half life of a few hundred
> years,
> that is not bad at all! The main issue with
> fission reactors is that the waste products have to be stored for hundreds
> of thousands of years. That's approaching geologic time scales. There are
> no truly "safe" places to put the waste. It may not occur to some people
> on the list, but the Grand Canyon had a very different climate 10000
> years ago (considerably more rain). It is not simple to estimate what the
> climatic conditions will be at a storage area 100000 year from now. It is
> perhaps reasonable to presume that large scale geologic upheavals will
> not occur in that time frame, but building a valt to withstand all
> foreseeable
> problems is a non-trivial matter.
>
> By Grace and Grace alone do we proceed,
> Wayne
>
Chuck gave a good perspective on this. I have a couple of other
thoughts.
First, the difference in half-lives conceals several other
factors. Keep in mind that the intensity of radioactive
material is inversely proportional to the half life. The more rapid
the rate of decay, the more intense a source will be and the shorter
its half life. Of course, a shitload of low activity material can
emit radiation as intensely as relatively little highly active
material and will do so for a very long time so the amounts of
material that are produced must be considered.
Second, the type of radiation and the type of material must be considered.
The long-lived isotopes (the transuranics, particularly plutonium) are
essentially poisons. They must be ingested to have any effect, and are
most deadly when breathed (recall plutonium is heavier than lead). I
am not saying plutonium is not dangerous. It is, particularly if there
is a chance of ingesting it.
Third, we live comfortably with natural poisons whose half life is
infinite (e.g. arsenic), and accept the mass production of many
others. I believe the volume of high level waste (highly radioactive)
produced in nuclear reactors is comparativley quite small.
In my opinion from my past history in the nuclear industry, most
people's fear of nuclear waste exceeds the real risk.
Hope this is helpful. I won't be able to say any more. I am leaving on
vacation, and have to finish a paper before taking off.
Blessings!
------------------------------------------------------------------------------
Joel W. Cannon | (724)223-6146
Physics Department |
Washington and Jefferson College |
Washington, PA 15301 |
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