 He was therefore willing to collaborate with Alvin Weinberg to allow the Oak Ridge National Laboratory to remain involved in reactor design.Nonetheless, reactor research accounted for almost half the laboratory's budget in 1949, and 84 percent of its research was classified.Zinn did not get along well with Captain Hyman G. Rickover, the US Navy's Director of Naval Reactors, but nonetheless Argonne assisted in the development of nuclear marine propulsion, eventually producing two reactors, a land-based prototype Mark I and a propulsion reactor, the Mark II.