Colorado’s 33,000 Pounds of Nuclear Waste Near Denver Raise Questions as Interest in New Reactors Grows
Why It Matters
Colorado is weighing a potential return to nuclear power generation, with Xcel Energy and some state legislators exploring smaller reactor options and the Department of Defense considering a compact reactor at Buckley Space Force Base in Aurora. But neither proposal comes with a long-term plan for handling radioactive waste — a problem Colorado already has, sitting in a massive concrete building roughly four miles east of Interstate 25, between Platteville and the Denver metro area.
What Happened
Colorado’s only commercial nuclear power plant, Fort St. Vrain, was completed in 1972 and began sending electricity to the grid in 1979. The helium-cooled facility was designed to outperform traditional water-cooled plants, but mechanical breakdowns driven by corrosion and electrical failures kept it operating at roughly 15 percent of its intended capacity. After another failure in 1989, the plant was decommissioned.
What remained was a significant amount of spent uranium fuel. Between 1980 and 1986, the U.S. Department of Energy transferred roughly 8 metric tons of spent fuel to Idaho National Laboratory. But political resistance in Idaho effectively ended further shipments in 1991, leaving approximately 15 metric tons — about 33,069 pounds — of spent fuel rods stored permanently on-site.
By the Numbers
- 33,069 pounds of spent nuclear fuel rods currently stored at Fort St. Vrain near Platteville
- 15% — the approximate share of its operational lifespan during which Fort St. Vrain actually generated commercial power
- 244 deep concrete-enclosed vaults inside the storage facility, holding containers of spent fuel
- 2031 — the expiration year of the facility’s current 20-year Nuclear Regulatory Commission license; one additional 20-year renewal is permitted under current agreements
- 4 — the total number of federally designated spent-fuel storage facilities in the United States, of which Fort St. Vrain is one
How the Waste Is Stored
Fort St. Vrain’s fuel was composed of highly enriched uranium blended with graphite and formed into rods roughly the size of a roll of quarters. Several thousand rods were packed into cylindrical fuel elements approximately 31 inches tall. After their useful life, those elements were stacked into long-term storage containers and lowered into concrete-lined vaults.
The storage building measures 143 feet long, 72 feet wide, and 80 feet tall. According to the Department of Energy, it is engineered to withstand tornado-force winds up to 360 miles per hour, flooding of up to six feet, and seismic activity. The structure is designed to remain functional for at least 40 years, potentially longer with proper upkeep. Cooling is handled passively, with fans drawing outside air through the vaults and exhausting it through roof vents.
The facility is at capacity and cannot accept waste from other sources. “The facility does not have the capacity for additional used nuclear fuel,” DOE communications director Justin Doil said. “It was designed for the unique fuel that powered the Fort Saint Vrain Nuclear Generating Station.”
Zoom Out
The waste storage dilemma at Fort St. Vrain reflects a national challenge with no near-term solution. Congress designated Yucca Mountain in Nevada as the country’s permanent underground nuclear repository, but the site has never opened after decades of political opposition, leaving spent fuel stranded at facilities across the country. The other three DOE-designated storage sites — Idaho National Laboratory, the Hanford site in Washington state, and the Savannah River site in South Carolina — face their own constraints and political pressures.
Meanwhile, cleanup liabilities from Colorado’s uranium processing history continue to generate legal and financial disputes, underscoring the long-tail costs associated with nuclear fuel at every stage of the cycle.
What’s Next
Fort St. Vrain’s current NRC license runs through 2031, with one additional 20-year renewal authorized. That means the waste near Platteville could remain in place at least until the 2050s under existing agreements, absent a federal breakthrough on permanent repository development. Any legislative push in Colorado toward new nuclear capacity would likely need to address waste handling before winning broad political support.