Saturday, January 10, 2009

Day 204: The Salt Advantage

Inside the salt dome bed sit drums of high-level transuranic waste, from WIPP's website

Today, I defer to others to discuss one of the topics that fills me with the most wonder, the role of salt in the long-term storage of nuclear waste.

Through the BLDG BLOG I have learned of a "research collective" named InfraNet Lab. In their blog post, The Advantages of Being Salty, they pose a most brilliant and simple question in response to the topic of salt and WIPP (the Waste Isolation Pilot Plant) located in Carlsbad, NM (Carlsbad Caverns is located within 30 miles of the site). WIPP is currently the only site in the United States accepting high-level transuranic waste (beyond uranium on the periodic chart). Language on WIPP's website claims to "dispose" of the waste by burying it deep within ancient salt domes beds. But since this waste doesn't simply evaporate or disappear from materially existing just by disappearing from human sight, I would argue that "attempts to permanently store" might be a better description for the situation unfolding here.

InfraNet Lab writes:

"The Waste Isolation Pilot Plant (WIPP) first opened in 1999 with the ambitions to permanently bury transuranic waste in our post-nuclear production age. Located 26 miles from Carlsbad, New Mexico, WIPP houses barrels of waste 2,150 feet below the surface. This site was chosen not only because of its remoteness but also because waste cold be embedded within a 3000 feet thick salt formation that has been stable for 250 million years. The underground salt formation from an ancient sea is just wet enough to move and seep slowly, therefore sealing the caverns after their construction. However, this also means that they would eventually flood. That is if it doesnt first collapse as it is predicted to do so before its 1000th birthday." They go on to write, "Maybe more significantly to us here is the role of salt (ancient seas) as burial grounds for toxic waste."

A statement worth pausing with today...

1 comment:

Anonymous said...

Jamie -

Your blog came up on a Google news search. I have several comments on your blog and one on the InfraNet Lab entry...

WIPP is located in a salt bed, not a salt dome - big difference: the first is structurally stable, the other is buoyant and unstable. The waste at WIPP is not high-level, it is transuranic (radionuclides heavier than uranium, such as plutonium, neptunium, americium, etc.). High-level waste has a specific definition in federal regulations. The waste is not being stored underground, it's being permanently disposed of - also a big difference. There is no intention to retrieve or recover the waste at a later date. Finally, there is no physical or stratigraphic connection between WIPP and Carlsbad Caverns.

On the InfraNet Lab article, there is general concensus that the disposal rooms will not "flood", but for modeling purposes it's assumed that there is sufficient liquid to totally degrade and consume the waste containers by oxidation (rusting). And I have no idea what they meant by "... if it doesn't first collapse as it is predicted to do before its 1000th birthday" (apparently meant to be within the first 1000 years). The salt flows plastically (creeps) and encases the waste - there may be occasional roof falls (note the pattern bolting in the ceiling in your photo), but eventually the cracks heal and seal to form a competent rock formation entombing the waste.

Hope this helps. For further references to WIPP, visit