Drilling technology proven in the oil and gas sector may offer a solution to the dilemma of how to dispose of nuclear waste. Deep Isolation, a California startup, has demonstrated the potential use of horizontal wells and prototype canisters for the geological disposal of such hazardous materials.

A wireline cable was used to insert a canister containing a steel rod simulating the weight of nuclear waste overThe drillhole waste repository concept. Source: Deep IsolationThe drillhole waste repository concept. Source: Deep Isolation 2,000 ft deep in an existing vertical drillhole that gradually curves until the opening is near-horizontal. This section has a slight upward tilt that provides additional isolation and waste immobilization. An underground tractor-type vehicle pushed the container further into this storage section, and then retrieved the canister several hours later.

After the waste is in place, the vertical access section of the drillhole and the beginning of its horizontal disposal section would be sealed using bentonite and other materials. The horizontal drilling technology that will be used is highly developed and can be implemented at a relatively low cost. Cost and safety are also improved by eliminating the requirement for the presence of personnel underground during construction.

About 80,000 tons of highly radioactive spent fuel from commercial nuclear power plants and millions of gallons of high-level nuclear waste from defense programs are now stored in pools, dry casks and large tanks at more than 75 sites in the U.S. As prospects for advancing the proposed Yucca Mountain geologic repository have dimmed with the withdrawal of government support and funding, the Deep Isolation system could provide an additional disposition pathway.

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