Nuclear power plays a crucial role in the U.S., contributing 19% of electricity generation and offering reliable, flexible, and carbon-free energy. As the nation strives to transition to a clean energy market following the Clean Power Plan by the EPA in 2015, nuclear technology becomes vital in achieving carbon emission reduction goals. However, uncertainties surround the expansion of nuclear power due to compounding influences from evolving climate, climate policies, and socioeconomics. This study explores nuclear power expansion pathways in the U.S. from 2015 to 2100 under diverse scenarios representing various future climates, decarbonization policies, and carbon capture and sequestration (CCS) availability. We use Global Change Analysis Model (GCAM) - USA, a detailed multi-sector dynamic model, to simulate climate-energy-water-land interactions and technology competition. It incorporates Generation II light water reactors (LWR), Generation III nuclear technology (assumes AP1000), and CCS technologies (coal, gas, refined fuels, biomass). Eight climate-socioeconomic scenarios (a mix of RCP 4.5/8.5 with hotter and cooler climates and SSP 3/5) and two CCS assumptions (with and without CCS) are considered to account for diverse future possibilities. Our findings reveal a decline-and-increase trend in total nuclear capacity, with Generation II reactors being phased out entirely by 2050 and different levels of Generation III reactors expanding through 2100 in all scenarios. A scenario featuring CCS, low emissions, and rapid population growth (RCP 4.5 cooler with SSP5) drives the most significant nuclear power buildout, increasing from around 100 GW in 2015 to over 150 GW in 2100. By 2100, Generation III nuclear power capacity in Texas, Florida, North Carolina, Alabama, and Montana collectively shares more than 30% of the total capacity in the U.S. In contrast, without emission constraints, nuclear power competes poorly with gas, leading to a decline to 13 GW by 2100 in the RCP8.5 hotter - SSP5 scenario. This exploration of alternative pathways offers insights into potential constraints for nuclear buildout in the U.S. based on climate, policies, and socioeconomic characteristics, emphasizing the need for sustainable and efficient transition to cleaner energy sources.