Sensible, Timely Relief for America's Nuclear Districts' Economic Development Act of 2021 or the STRANDED Act of 2021 This bill provides resources to communities that are challenged by stranded nuclear waste. The bill requires the Department of Energy (DOE) to establish a competitive prize competition for affected communities to carry out alternatives to nuclear facilities, generating sites, and waste sites. DOE must also (1) establish the Stranded Nuclear Waste Task Force to study existing public and private resources and funding for affected communities, and (2) establish a grant program to assist localities near nuclear power plants to offset the impacts of stranded nuclear waste in affected communities.