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The initial node that prompted these comments has since disappeared, for reasons unknown. If I recall correctly, the write-up made a case in favor of nuclear power that (to my mind) skipped some critical questions on the storage of radioactive reaction waste products. It has been some time since I followed this closely, so my comments may be based on somewhat outmoded data. One noder, for instance, suggests that storage in glass is an effective, absolutely permanent form of containment, preventing the issues of migration that are amongst my gravest concerns with nuclear waste management.

Being the life partner of a radiologist, I can't exactly be less than subjective here, but I would like to see more detail about how one predicts what will happen in any particular geological setting 100,000 years in the future.

That contingency remains my strongest remaining reservation about fission power. I have no reservations concerning fusion, should it someday prove itself cost-effective. The chief perceived weakness that I see in the preceding write-up still concerns the intersection of long term storage and geological events. Perhaps an expansion on how one can be reasonably sure that today's desert will not become open ocean between now and the time when the waste's isotopes have decayed to acceptable levels would allay those concerns for myself and others?

Then again, I also grew up in a part of the country where all residents were estimated to received the equivalent of several chest X-rays in rads each year, between the ambient radiation levels at high altitudes, having been downwind of the Nevada A-bomb tests, and the high uranium content in the local soil and rocks, so why am I worried anyhow?

The only reason that nuclear waste from fission is even an issue here in the United States is that our government refuses to allow the reprocessing of spent fuel, because for one brief step in that process, bomb-grade plutonium is produced before being mixed with uranium-235 and less fissionable isotopes, typically uranium-238, to form mixed-oxide fuel. We are the only nuclear nation in the world to not reprocess our spent fuel. (Former President Jimmy Carter made the executive order on this.)

The remainder of spent fuel is various daughter products of (primarily) U-235 and Pu-239 fission. These isotopes have much shorter half-lives than conventional nuclear fuels, and after ten or so years are pretty much harmless.

Fusion power is not entirely free of waste either. Deuterium-tritium fusion, which is much easier to start and control than deuterium-deuterium fusion (I won't even bring up helium-3-deuterium fusion, as there are no viable He3 sources nearer than Jupiter), produces helium-4 and a neutron as the fusion by-products. These neutrons collide with the steel shielding, specifically designed to trap them. However, over time, enough neutrons collide with the steel that it becomes radioactive, which brings us back to the radioactive waste problem of fission, except this waste can't really be reprocessed into anything useful, until it decays to negligible levels, which, depending on what isotope of iron it reaches before it begins decaying, could be millions of years.

As for obtaining the fuel for fusion, this can be done entirely automatically by extracting heavy water from ocean water, electrolyzing it, and then separating the hydrogen isotopes. Protium would be reacted with the oxygen and released back to the ocean, while deuterium and tritium would be stored for fusion. This process is even safer than mining uranium, because there are almost no workers involved.

I need to go find my bibliography...

The process for safely confining radio-nuclides is to first burn it to oxidise it and then to mix the ash/powder with silicon to form glass. This then is quite stable and won't leach into the water table because it can be buried in deep mines and will not react with the water.

Another point worth noting is that fuel rods are not now continuous lengths of uranium. The latest designs of uranium use fail safe technology.

Pellets of uranium are inserted in zirconium tubes between Boron pellets. As the Boron becomes too hot, natural expansion forces the uranium pellets apart, lowering the neutron absorption and naturally cutting off the nuclear reaction. This system does not rely upon human intervention. It works to cut off the reaction automatically when a traditional reactor would runaway and suffer a steam explosion.

This is only an example of how classic nuclear power reactors have evolved. One could reasonably say that technology has moved on whilst paranoia about nuclear power hasn't. Not only have traditional designs of nuclear reactors evolved but now there are revolutionary new designs of alternative nuclear reactors such as the ADS, or Accelerator Driven System championed by Carlo Rubbia. This uses fail safe technology, has no moving parts and may be switched on, or off, at will. It does not use Uranium or Plutonium at all and the design is so simple, that runaway nuclear reactions are impossible

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