Reactor Operating Characteristics
Prerequisites
New nuclear plants cost $10,000+ per kilowatt to build, yet existing nuclear plants produce electricity at roughly $30/MWh, cheaper than almost any other zero-carbon source. The asset that was expensive to build is cheap to run, and that gap shapes every policy debate about nuclear's future.
Once built, nuclear operating costs split into fuel, operations and maintenance, and capital recovery. Uranium fuel is cheap relative to electricity output because fission energy density is enormous: a single fuel pellet the size of a fingertip holds as much energy as 17,000 cubic feet of natural gas. That low fuel cost, combined with continuous-output design, lets nuclear plants run at capacity factors above 90% year after year. Plants licensed for 40 years are routinely relicensed to 60, and the NRC has begun approving 80-year licenses.
Running the numbers. A 1,200 MW plant at 92% capacity factor produces about 9.7 billion kWh per year. Fuel cost is roughly $7/MWh, operations $12/MWh.
How does the all-in operating cost compare to a gas plant paying $30-50/MWh in fuel alone?
Existing nuclear wins on marginal cost. All-in operating cost lands near $25-35/MWh. A fully depreciated plant carries zero construction debt. An existing nuclear plant with sunk costs is among the cheapest electricity sources on the grid.
When a state considers closing an existing nuclear plant, it is walking away from a low-cost, always-on, zero-carbon source that would cost $10 billion or more to replace. Distinguishing the economics of existing nuclear from new nuclear is the first step in evaluating fleet retirement arguments.
Why do existing nuclear plants have much lower electricity costs than newly built ones?
Nuclear's high capital cost is a fixed charge spread over decades. Once construction debt is retired, remaining operating cost (fuel plus O&M) is low, making existing plants highly cost-competitive.
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