Byron Station consists of two pressurized water reactors, termed Byron Unit One and Byron Unit Two, and the surrounding grounds and facilities. Byron Unit One received its operating license from the NRC on February 14, 1985 and Unit Two received its license on January 30, 1987. On September 16, 1985, Unit One entered commercial service and power began to be generated at Byron. The operating licenses for the two reactors are set to expire two years apart: Initially, Unit One's license expired on October 31, 2024, and Unit Two's on November 6, 2026? On May 29, 2013 Exelon Generation Co. applied to renew the licences and on November 19, 2015, based on a final safety evaluation report (July 6, 2015) and a supplemental environmental impact statement (July 15, 2015), the Nuclear Regulatory Commission renewed both operating licenses for an additional 20 years. The renewed licenses authorize Unit One to operate through October 31, 2044, and Unit Two through Nov. 6, 2046.