R. Scott Kemp continues his MIT course 22.04, Social Problems of Nuclear Energy, with the second half of a lecture on how the civilian nuclear fuel cycle connects to weapons proliferation. He walks through uranium enrichment and plutonium reprocessing as the two technical pathways that link peaceful nuclear power to bomb-making capability, building on the first part's introduction. The eighty-minute session is a continuation lecture, assuming familiarity with the fuel cycle basics covered previously, and goes deeper into how enrichment levels and reprocessing technology determine how close a civil program sits to weapons capability. This is a straight technical and policy lecture from an MIT graduate course, aimed at students who need to understand the hard engineering constraints behind nonproliferation debates rather than a general audience introduction to the topic.