How did North Korea's nuclear research community develop in the context of its science and technology policy, and how did this development reflect progress in North Korea's nuclear program? We conduct network analysis using a dataset of North Korean domestic scientific journal articles to assess the structure of the North Korea's nuclear research communities from the beginning of the country's nuclear program until its capability "completion" in 2018. We find that the networks showed increasing internal density of research collaborations, suggesting North Korea was able to improve knowledge transfer, and consolidate its nuclear research community over time. Furthermore, different areas of nuclear-related research increased interconnectivity over time, particularly in the run-up to milestones in North Korea's nuclear development. We close with implications for engaging with North Korea on science and technology issues.