{"docs":"https://nuclearnewsnetwork.com/tracker","unit":{"slug":"natrium-kemmerer-1","name":"Natrium Demonstration (Kemmerer)","plant":"Kemmerer Power Station","unit":1,"country":"US","region":"north-america","reactor_type":"SFR","design":"Natrium (sodium-cooled fast reactor + molten salt storage)","capacity_mw_net":345,"is_smr":true,"vendor":"TerraPower","owner_operator":"TerraPower / PacifiCorp offtake","status":"under_construction","construction_start":"2024-06-10","original_cod_target":2030,"current_cod_estimate":2031,"milestones":[{"date":"2024-06-10","event":"Non-nuclear construction began at Kemmerer, Wyoming","source":"https://www.terrapower.com/"},{"date":"2026-03-04","event":"NRC issued Part 50 construction permit — first commercial non-light-water US power reactor permit in 40+ years","source":"https://www.energy.gov/ne/articles/nrc-issues-construction-permit-terrapowers-natrium-advanced-reactor"},{"date":"2026-04-23","event":"Nuclear construction officially commenced; owner expects construction complete by February 2031","source":"https://www.terrapower.com/TerraPower-Commences-Construction-on-Americas-First-Utility-Scale-Advanced-Nuclear-Power-Plant"}],"sources":["https://www.terrapower.com/"],"last_verified":"2026-07-10","verified":true,"confidence":"high","notes":"First US utility-scale advanced reactor in construction; coal-to-nuclear flagship. HALEU supply is the program watch item.","tags":["usa","advanced-reactor","terrapower","sfr","doe-arpd"],"updated_at":"2026-07-10","slippage_years":1}}