Next Generation Nuclear Advancement Act of 2020 This bill addresses advanced nuclear energy research and development programs at the Department of Energy (DOE). Specifically, DOE must establish an Integrated Energy Systems Program to maximize energy production and efficiency; develop energy systems involving the integration of nuclear energy with renewable energy, fossil energy, and energy storage; expand the use of emissions-reducing energy technologies into nonelectric sectors to achieve significant reductions in environmental emissions; carry out a light water reactor sustainability program that includes ensuring the achievement of maximum benefits from existing nuclear generation, and promoting the use of high-performance computing to simulate nuclear reactor processes; and develop and submit to Congress a 10-year strategic plan for its Office of Nuclear Energy.