Sunday, November 13, 2011

Nuclear Waste: One Man’s Trash…

… is another man’s treasure.

In my mind, this adage is very applicable to the treatment of so-called ‘nuclear waste’. To be clear, nuclear ‘waste’ can come in many forms; from the steam generators that are being recycled by the Bruce A Restart project to the spent fuel bundles (or rods) ejected from the core. Not all these ‘wastes’ are created equal, but many if not all of them share one thing in common; they are still valuable resources.

The contaminated steam generators that Bruce Power planned on recycling to reduce the amount of waste are a good example to start with. To explain quickly, the steam generators are used in a CANDU reactor to transfer the heat from one water cycle to another. The two cycles are separated but heat is transferred from one cycle to the next by thermal contact across kilometres of piping. After decades of use, fixed material has built up on the interior of these pipes, some of it radioactive. [1]

At first, the plan was to safely store the entire steam generators for as long as is necessary, until it was proposed that the steam generators be shipped off to Sweden to have most of the metal recycled and the remaining radioactive material returned for long term storage. While seemingly a better proposal, it ran into immediate opposition by environmental groups, despite confirmation by the Canadian Nuclear Safety Commission (CNSC) that the plan was safe even if the boat sank [2].




Another good example is the treatment of tritium in Canada, which I’ve mentioned before. Long considered a waste, an unfortunate bi-product of using heavy water (water that contains deuterium), tritium was and continues to be released in a controlled manner into the Great Lakes. In accident situations, tritium can be released into the environment as well [3]. Since 1990 though, Darlington has hosted the “Tritium Removal Facility”, which removes tritium from the water and stores it as a gas on titanium [4]. This tritium can be used directly in nuclear fusion, or after decaying into Helium-3 can be used in low temperatures physics and even bomb detection devices. Helium-3 specifically continues to be in very high demand [5].

Finally, even the spent fuel bundles can be ‘recycled’ through reprocessing. If you consider a cycle with the spent fuel rods from light water reactors (which are inefficient from a neutron standpoint) being reprocessed into fuel bundles for heavy water reactors (which are efficient from a neutron standpoint), one can see the benefits. [6] This is something I hope to cover in more depth later.

These are just the uses that we know of now, as has been proven time and again, our abilities to find uses for the things once thought of as waste is immeasurable. Perhaps then we should be hesitant to place so-called 'wastes' into permanent storage facilities the barriers to accessing them are unnecessarily prohibitive.


References

[1] "The Right Thing to Do" www.therightthingtodo.ca (A website created by Bruce Power concerning the recycling of the steam generators)

[2] CNSC assessment concerning the proposed transportation of the steam generators [pdf]

[3] "Report and Advice on the Ontario Drinking Water Quality Standard for Tritium" Ontario Drinking Water Advisory Council, May 21st, 2009 [pdf]

[4] "Evaluation of Facilities Handling Tritium", Canadian Nuclear Safety Commission, February 2010 [pdf]

[5] Christina Reed, "The Fallout of a Helium-3 Crisis", Discovery News, February 19th, 2011. [link]

[6] "Processing of Used Nuclear Fuel", World Nuclear Association, November 7th, 2011. [link]

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