US companies prepare for borehole field tests

22 December 2016

The US Department of Energy (DOE) has selected four companies to explore the possibility of conducting a deep borehole field test. One will ultimately be chosen to test the feasibility of engineering deep boreholes that might offer an alternative to mined geologic repositories for the disposal of some forms of nuclear waste.

The four companies selected by the DOE are: AECOM, exploring a site in Texas; ENERCON, exploring a site in New Mexico; TerranearPMC, also exploring a site in New Mexico; and RE/SPEC, exploring a site in South Dakota. Each of the companies will work closely with the communities surrounding the proposed test sites and must work to reach a "cooperative and mutually beneficial" agreement with them before any drilling takes place. Only those that establish such an agreement will go forward in the competition for the final site selection.

The DOE has chosen a phased approach to the feasibility project after efforts to begin deep borehole studies earlier this year at sites in North and South Dakota were shelved. In January, the DOE announced that a team led by Battelle Memorial Institute had been selected to drill a 16,000 feet (4880 metre) test borehole into a crystalline basement rock formation at a site in Rugby, North Dakota. However, efforts by the DOE and its contractor failed to address community concerns that they would be required by the federal government to accept waste in the future. "[I]t became clear that insufficient initial communication and outreach created a negative impression of the project that resulted in community opposition of the proposed deep borehole field test. As a result, DOE decided to withdraw the project," US under secretary for science and energy, Lynn Orr, said this week.

"Based on this experience, DOE revised the request for proposals to reflect the Department's understanding that public engagement and support for this project is paramount, and to make completely clear that the field test site would not be used for future nuclear waste disposal," Orr said.

No nuclear waste will be involved in the field test, and the contract specifically prohibits the storage, disposal or use of nuclear waste at the site of the test. After the project is completed, the borehole will be permanently sealed and the land restored.

The DOE is particularly interested in evaluating whether deep boreholes - narrow, vertical holes drilled deep into the earth's crust - might offer an alternative to mined geologic repositories for nuclear waste. Compared with deep geological disposal in a mined underground repository - typically at depths between 250 and 1000 metres - placement in deep boreholes is generally considered to be a more expensive option for large volumes of waste but may be an attractive proposition for the disposal of smaller waste forms.

The study will collect data on rock types, water chemistry, rock temperatures and other geologic data to see if nuclear waste disposal is feasible in this kind of geology, but will also provide a unique opportunity to gather other deep local geologic data and may have follow-on potential for geothermal research, according to the DOE.

Researched and written
by World Nuclear News