Comment by sehansen

In a nuclear energy context "closed cycle" just means that the uranium and plutonium is separated out from the spent fuel for future reuse. The loop is only closed in the sense that some of the spent fuel material that leaves the reactor will enter it again in the future. It doesn't imply that new inputs won't be added to the loop.

https://en.wikipedia.org/wiki/Nuclear_fuel_cycle_in_France#C...