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Projected vs. actual cost and lead-time of U.S. nuclear power plants, 1966–1977 standard practice vs combined heat and power


Nuclear power plants have a history of major cost overruns and missed deadlines. Of plants whose construction was started prior to 1977, the average actual construction costs were two to three times higher than the average projected cost. The average project was extended at least three years beyond its original completion date. Delays and real cost escalation in France’s uniquely organized reactor program followed a broadly similar pattern.

This analysis by the U.S. Energy Information Administration in 1986 includes overnight costs (the cost in the absence of financing and escalation costs) and lead-times for 75 nuclear plants that became operational before 1986. Only 12 nuclear plants have been built in the United States since, with the last of these coming online in 1993. The massive cost and lead-time overruns were caused by many interrelated factors including a turbulent regulatory climate, unstandardized system designs, challenges in managing complex, multi-year projects, and a deteriorating attitude towards investments in nuclear energy.

These experiences are not unique to projects in the U.S. Two large European projects underway—Finland’s Olkiluoto-3 and France’s Flamanville-3—are both at least three years behind schedule and dramatically over budget.


Energy Information Administration. 1986. An Analysis of Nuclear Power Plant Construction Costs. Washington, D.C.: U.S. Department of Energy.

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