Colorado’s history with nuclear energy is limited. Only one nuclear reactor has been built in the state, and it has since closed down. The plant was located east of I-25 near Plateville, and was named the Fort Saint Vrain Plant. It was built, owned, and operated, in a limited capacity, by the Public Service Company of Colorado, which now goes by the name Xcel Energy.
The Public Service Company acquired a license to build their high-temperature, gas-cooled reactor in 1973, and invested $240 million to build it. The plant began operating in 1979, and remained in operation for 10 years. Until it was transformed in 1989, it only operated, on average, at about 14.6% it capacity. In 1989, the Public Service Company transformed it into a natural gas electric generator for an additional $340 million, and spent $25 million to build a spent fuel storage. This fuel storage is still on site and is under the discretion of the United States Department of Energy.
Though there have been no other nuclear energy reactors in Colorado, the state has a significant history with uranium mining, which is a primary source of fuel for nuclear energy. The state’s history with uranium mining dates back to the early 1900s, when radium and vanadium experienced a huge production boom, which are accessory minerals to uranium.
During the 1940s due to the emergence of nuclear weapons, uranium was specifically targeted in Colorado in mass, which continued through the 90s due to a potential nuclear energy increase in the United States. One of the most significant producers of uranium in Colorado is the Uravan Mining District in Montrose County which contributed over 850 tons of Uranium to the Manhattan Project. From 1947 to 1970, the Uravan district mined and produced around 24 million pounds of uranium ore. Along with the Uravan Mining District, Colorado has hosted the Schwartzwalder Mine in Boulder, which produced 17 million pounds of uranium ore; the Thornburg mine, which produced 1.25 million pounds of uranium ore; the Cyprus Hill mine at Hansen Creek, which produced 25 million pounds of low grade uranium ore; and many other smaller operations.
According to the Colorado Energy Office, there has been no uranium mining in the state of Colorado since 2009. However, there are still 18 active uranium mining sites permitted, 12 on temporary cessation, and 1 pending approval in the state as of 2014. Though these active mines are permitted, none are actually operating.