Jonathan_S wrote:Theemile wrote:The US has had a number of pebble bed reactors for military applications over the years. In the 90's "project Timberwind" using a pebble bed reactor to heat rocket exhaust was pushed by DARPA as an alternative to the Atlas V/Delta IV Rockets then in development. In the 50s and 60s, the Air Force actually built pre-production pebble bed reactors for "project Pluto" (Nuclear ramjet missile) and "project Weatherman" (Atomic manned bomber) and tested them fully before public/congressional backlash (and the development of ICBMs)shut down the programs. Projects ROVER and NERVA also toyed with the pebble bed design.
Several working full scale prototypes of the ramjet pebble bed reactor, starting with the Tory-IIA reactor(made by COORS!), actually "flew" in a special wind tunnel at Jackass Flats (near area 51) in the early 1960s before the Pluto project was canceled in 1964.
Huh, I'd never heard that Project NERVA ever looked at pebble-bed technology. Certainly the prototype nuclear thermal engines they actually built and tested at Jackass Flats weren't -- those had the nuclear fuel in solid core fuel rod elements.
Different rod technology. It was a variation on a pebble bed technology with 50,000 ceramic separator rods in the bed.