Sandia National Labs suggests we take another look at underground salt deposits for nuclear waste

Apr 04, 2011 by Bob Yirka report

(PhysOrg.com) -- In light of the Obama administration's decision to effectively end the discussion of using the Yucca mountain site in Nevada as a location for permanent storage of nuclear waste, Sandia National Laboratories, (SNL) headquartered in Albuquerque, NM, has released a paper wherein it calls for new discussions about the possibility of using underground salt deposits to permanently store the nation’s growing stockpile of nuclear waste.

In the paper, the authors, Frank D. Hansen and Christi D. Leigh, note that the United States has several major underground salt deposits and has identified two sites they believe would be able to accommodate a repository; the salt domes on the Gulf coast and the bedded salt in Davis and Lavender Canyons in Utah.

Hansen and Leigh also note that a lot of testing over nearly 50 years has already been done regarding the feasibility of storing radioactive material in underground salt deposits, both in this country and in Germany; most of which was done using heaters though, instead of actual fissionable material, due to the hazardous nature of working with such materials. The objective was to determine if radioactive heat would cause the dislocation of minute quantities of water imbedded in underground salt, causing it to move. All of the tests done to date thus far have confirmed the author’s belief that underground salt deposits are our current best option. They further noted that three atomic explosions were conducted in underground salt deposits in the early 50’s with none of them reporting any leakage after more than fifty years.

The idea of using underground salt deposits is a strong one in this country due to the fact that the United States has several very large natural salt fields, some nearly as thick as a mile, and that lie between 1 and 2 miles below the surface; and to the fact that the US is currently housing an enormous amount of both High Level nuclear Waste (HLW) and Used Nuclear Fuel (UNF) in temporary storage facilities. The recent disaster at the Fukushima plant in Japan has highlighted the dangers of storing such materials in temporary facilities and new calls for finding a permanent storage facility for nuclear waste are already being heard in Washington.

One of the chief benefits of using a salt deposit, rather than those of shale or other rock formations is that salt isn’t nearly as susceptible to disruption as are rock formations. Salt has a self-sealing property due to its makeup and the weight and pressure of the salt and rock that surrounds it. In addition salt deposits are considered to be nearly impervious to geological disruptions such as earthquakes due to their soft nature, i.e. they tend to slide around rather than crack and break.

The Department of Energy has appointed a commission to come up with recommendations for storage of nuclear wastes and is expected to report its findings in the coming months.

Explore further: Should the role of afforestation in climate change mitigation policy be re-evaluated?

More information: brc.gov/e-mails/January%2011/A… _SAND-01-13-2011.pdf
via Newscientist

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User comments : 4

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Bigblumpkin36
not rated yet Apr 04, 2011
SEnd it to the mars polar ice and heat that planet up then we can inhabit it in 10,000 years
Bigblumpkin36
not rated yet Apr 04, 2011
Anyone no how long it takes for N-waste to become stable or is it a lost cause?
eachus
not rated yet Apr 05, 2011
Once you understand the issues, the whole debate about storing long-term nuclear waste is a farce. Start with a mix of Uranium isotopes, and enrich the U235 to about three per cent (from 0.7%) for commercial nuclear reactors. In about 4.5 billion years, you will have half as much U238 and the other isotopes U-235 plus small amounts of U233 and U236, will all be gone.

Of course, if it had never been near a nuclear reactor, you would still have about the same thing, and if you go out in your back yard and chip a sample of granite, it will contain Uranium, and half of it will decay in 4.5 billion years. So there is never a point at which this "waste" is non-radioactive.

What about the radioactive isotopes from splitting the Uranium? That's the secret that they don't tell you. When the Uranium fissions you get highly radioactive neutron rich isotopes. Most of these decay by neutron emission within a few seconds. That's what makes the nuclear reactor controllable.
eachus
not rated yet Apr 05, 2011
There are some isotopes in there with extremely long half-lives, like the Uranium. But if you look at all of Uranium's favorite children and their decay chains, the maximum half-lives of most are under ten years. If you plan based on the longest half-lives--well that is U-238, and there sure is a lot in there. Strontium-90 and Cesium-137 with half lives around 30 year, are about all you really have to worry about. In three hundred years, the intensity of radiation from these two will have dropped by about 1000x. Wait 600 years, another factor of 1000, and you are to the point where replenishment from spontaneous fission in the Uranium will account for more radiation than the remaining original decay products.

So in 600 year (or perhaps earlier) our children will be treating the spent fuel dumps as a source for Uranium for new reactors.

If you want to add another hundred years "just to be safe." Fine. But anyone talking thousands of years is selling snake oil.

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