Deep Fission completes borehole demonstration

California-based Deep Fission is developing the Gravity reactor, a small modular reactor designed to be placed underground in an optimised borehole one mile (1.6 km) deep.

The company has announced that it has now successfully lowered the 20 foot (6 metre) canister to a depth of 100 feet inside a 34 inch (86 centimetre) wide borehole, aligned it, and brought it back to the surface, an emplacement and retrieval sequence that Deep Fission's deployment model depends on. The prototype canister is a full-size, non-nuclear replica of the canister designed to house the Gravity reactor core. 

_{(Image from Deep Vision's video)}

The process was carried out using standard commercial drilling equipment operated by a commercial drilling and rigging crew: nothing about the demonstration required equipment that had to be invented, custom-built, or adapted for nuclear service, the company said.

"The most important thing about this demonstration is what we did not have to do," Deep Fission CEO Liz Muller said. "We did not have to develop new technology. We used a rig and rigging that is commercially available in the field today, and our reactor uses pressurised water technology that has been operating in the nuclear industry for decades. Our innovation is in how we put proven pieces together, not in inventing something that has never been built. That is the difference between a science project and something you can deploy."

The demonstration took place on 3 September and is part of a commercial validation programme that also includes drilling, system integration, regulatory approvals and ultimately, commercial operation, the company said.