The year was 1972. The proposed salt repository at Lyons, Kansas was in its death throes. Environmentalists were demanding a solution to the waste problem or shutting down the entire nuclear industry. Caught off guard, the AEC contracted with the US Geological Survey to study other geologic media, look further afield, think outside the salt-box. Dr. Isaac “Ike” Winograd, a research scientist for the USGS, had been doing just that. At the annual meeting of the Geological Society of America, Ike proposed using the thick unsaturated zone somewhere in the American Southwest for long-term storage of solidified high-level waste. In the world of high-level radioactive waste, this was quite the revolutionary idea.

For over a decade, burial in salt had been essentially the only game in town. The USGS had a long-standing concern with this medium – salt can behave in a highly unpredictable manner in the presence of the extremely high heat generated by high-level waste. The other option being considered for geologic disposal was to bury the waste below the water table, deep in the saturated zone. Burying the waste in water would protect the canisters from oxidation. Uranium in the spent fuel is also more stable in the absence of oxygen. Yet, even then, eventually the canisters would be breached and radionuclides released. A major challenge with a saturated-zone repository was how to build a solid, secure repository surrounded by all that water, and then seal it back up.