A good recent survey of the state of our thinking on extraterrestrial life is Paul Davies’ Are We Alone? (Penguin Books, 1995). The passages set on the Moon are based in part on conversations with former astronaut Charles M. Duke, who in 1972 walked on the Moon as Lunar Module Pilot of Apollo 16. There really are naturally occurring nuclear reactors; a reference is ‘Fossil Nuclear Reactors’ by Michel Maurette, Annual Review of Nuclear Science v 26, pp319–350 (1976). I published a technical article on the feasibility of the Moon’s deep ocean in the Journal of the British Interplanetary Society (v 51, pp 75–80, 1998).
Any errors, omissions or misinterpretations are of course my responsibility.