This was called the "Deep Well Reactor" concept back in 1984. https://babel.hathitrust.org/cgi/pt?id=mdp.39015012182435&seq=73 https://babel.hathitrust.org/cgi/

This was called the "Deep Well Reactor" concept back in 1984. https://babel.hathitrust.org/cgi/pt?id=mdp.39015012182435&seq=73 https://babel.hathitrust.org/cgi/pt?id=mdp.39015012182435&se... You have serious constraints in neutronics when constrained to a drillable borehole diameter and low-enriched uranium. The radial peaking will be high. May still be an ok tradeoff.