Ian's Rant – Burying Nuclear Waste

Radioactive nuclear waste

Ian's alternative solution for the disposal of nuclear waste.

Posted: Jun-2003

Nuclear Waste Disposal

I can't understand the difficulty governments have disposing of nuclear waste materials. Can't they just put it back in the same place they dug it up from in the first place?

Somewhere out there, dotted around the map, are uranium mines where they dig up low-level radioactive bearing ore. Putting the “spent” radioactive materials back in the original hole is surely no more dangerous to that area, or to those people, or to the environment, than the original radioactive ore that came out of it?

And if my un-scientific assumptions are incorrect, and the refined nuclear material has been brought to a higher level of radioactivity than the original ore, then it seems only fitting that it goes back to where it came from so that those land-owners who profited by its extraction should be the ones who have to deal with the dangerous legacy that they themselves instigated.

– Ian Fieggen, Jun-2003

Nuclear Waste Figures

From the International Atomic Energy Agency's web site (http://www.iaea.org), Jun-2003:

Each year the world’s 441 nuclear power reactors create enough spent fuel to fill a football field. That’s about 10,500 tonnes of heavy metal. This waste is thermally hot and can stay radioactive for thousands of years. Because it is solid and does not readily dissolve in water, the fuel wastes are typically stored in water pools on site at the nuclear reactors for many years.

But permanent disposal places are needed. Scientists warn that the ongoing storage of spent fuel is not sustainable for the long years needed for the waste to decay and lose its radioactivity. Right now only one permanent disposal facility exists in New Mexico where long-lived radioactive waste from United States military programmes is carefully packaged and cocooned in tunnels deep underground, in what is called a geological repository.

Visitor Feedback

My feedback is on your Rant about nuclear waste. In particular, your solution for nuclear waste, which fails to take into account the nuclear fuel cycle.

First step is concentration of the ore, which increases radiation intensity. Next is isotope separation, U238 – U235 ratio is changed. The more U235, the more radioactive it gets due to the difference in half-life. U238 is 4*10^10 years, while U235 is 7*10^8 years. For fuel rods, U235 is increased from the natural rate of 0.7% up to 5% or so, depending on the reactor design.

See http://en.wikipedia.org/wiki/Enriched_uranium for some details.

But your suggestion would perhaps be feasible the only issue was the requirement to de-concentrate the isotopes and turn the uranium back into ore ... the problems would be technical and economic, but it would just be a form of reclamation-recycling.

The real problem is in the fuel cycle itself ... a nuclear reactor is a fission plant, and the natural decay of the U235 is used to initiate fission in the fuel rod. The fission by-products are often radioactive, and have much shorter half lives.

See http://en.wikipedia.org/wiki/Nuclear_fuel_cycle for some details.

The result is that the used fuel rods are much “hotter” than the new ones, and have a very different chemical composition ... with some forming water-soluble compounds.

So nuclear fuel reprocessing is required see http://en.wikipedia.org/wiki/Nuclear_reprocessing for details. The true nuclear waste is what is left over from that, and it is quite hot, and very nasty.

This leads us to spent nuclear fuel, see http://en.wikipedia.org/wiki/Spent_nuclear_fuel_shipping_cask.

– Peter D., Jun-2007

Ian's Reply: Thanks for detailing this – very interesting. In particular the fact that there are some water soluble compounds. I will take some time today to go through the links you sent.

I wonder, though, whether the solution could be as simple as grinding the rods into a very fine powder and mixing it sparsely back into the earth from which the uranium was originally separated before depositing back into previously worked parts of the uranium mine. This would also eliminate the possible problem of “terrorists” gaining access to the wastes because it would be both uneconomical and hazardous to try to dig up all that earth in order to reclaim the finely dispersed radioactive powder.

– Ian Fieggen, Jun-2007