Nuclear Power Uprate Calculator
A power uprate is an NRC-approved increase in an existing nuclear plant's licensed maximum generating capacity — achieved through instrumentation improvements, turbine/generator upgrades, or other plant modifications rather than building a new reactor. This calculator takes the current plant capacity, an uprate percentage, an uprate cost per kW, and a new-build cost per kW, then reports the additional capacity gained, the uprate project cost, the equivalent new-build cost for that same added capacity, and the resulting cost savings versus building new. It pairs naturally with our Nuclear Plant Capacity Factor & Output Calculator for the generation side of the same plant, and our planned SMR vs. Traditional Large Reactor Cost Comparison Calculator for the broader new-build cost context.
1,100 MW is representative of a large single-unit nuclear reactor.
Selecting a type auto-fills the uprate percentage below (still editable). NRC-approved uprates range from small instrumentation-based recapture up to larger extended uprates requiring significant plant modifications.
NRC-approved uprates fall into three general categories, ranging from small instrumentation-based recapture up to larger extended uprates requiring significant plant modifications.
Uprate costs (turbine, generator, and balance-of-plant modifications to an existing licensed facility) are typically far cheaper per kW than new construction, since the reactor, containment, and most site infrastructure already exist.
Used for comparison only -- see the SMR LCOE Calculator or SMR vs. Traditional Reactor Cost Comparison Calculator for new-build cost context.
current plant capacity (MW) × (uprate percentage (%) ÷ 100)
additional capacity from uprate (MW) × 1000 × uprate cost per kW ($/kW)
additional capacity from uprate (MW) × 1000 × new-build cost per kW ($/kW)
equivalent new-build cost ($) − uprate project cost ($) · savings % = (savings ÷ equivalent new-build cost) × 100
Results update live as you type. For planning and field-check estimates — always verify against applicable standards and equipment ratings.
How we calculate this →Power uprates are widely considered one of the cheapest ways to add nuclear capacity, because the reactor, containment structure, and most site infrastructure already exist and are already licensed. A 7% stretch uprate on a 1,100 MW plant adds 77 MW at roughly $154 million -- about 60% less than building that same 77 MW of new capacity from scratch. The U.S. nuclear fleet has added thousands of megawatts of capacity through NRC-approved uprates over the past several decades, largely without the multi-year construction timelines and licensing burden of a brand-new plant.
How nuclear power uprate is calculated
This calculator estimates the additional capacity gained from a nuclear power uprate, the cost of the uprate project, the equivalent cost of building that same added capacity from scratch, and the resulting cost savings versus new-build. Five quantities tie the calculation together.
Additional Capacity from Uprate (MW) = Current Plant Capacity (MW) × (Uprate Percentage (%) ÷ 100). The uprate percentage is the NRC-approved increase in the plant's licensed maximum generating capacity, expressed as a share of the current nameplate rating. At the defaults (1,100 MW and 7% stretch uprate), that is 1,100 × 0.07 = 77 MW.
Uprate Project Cost ($) = Additional Capacity from Uprate (MW) × 1000 × Uprate Cost per kW ($/kW). Converting the added capacity from megawatts to kilowatts (× 1000) and multiplying by the uprate cost per kW gives the total cost of the turbine, generator, and balance-of-plant modifications needed to handle the additional output. At the defaults (77 MW and $2,000/kW), that is 77 × 1000 × $2,000 = $154,000,000.
Equivalent New-Build Cost for Same Capacity ($) = Additional Capacity from Uprate (MW) × 1000 × New-Build Cost per kW ($/kW). This is what it would cost to build that same added capacity as a brand-new plant, using the new-build cost per kW for comparison. At the defaults (77 MW and $5,000/kW), that is 77 × 1000 × $5,000 = $385,000,000.
Cost Savings vs. New-Build ($) = Equivalent New-Build Cost for Same Capacity ($) − Uprate Project Cost ($). Subtracting the uprate project cost from the equivalent new-build cost gives the dollar savings from uprating rather than building new. At the defaults, that is $385,000,000 − $154,000,000 = $231,000,000.
Cost Savings vs. New-Build (%) = (Cost Savings vs. New-Build ($) ÷ Equivalent New-Build Cost for Same Capacity ($)) × 100. This expresses the savings as a share of the new-build cost, showing how much cheaper the uprate is per unit of added capacity. At the defaults, that is (231,000,000 ÷ 385,000,000) × 100 = 60.0%.
Two notes on the model. First, the uprate and new-build cost-per-kW figures are representative ranges from industry technical reports; actual uprate costs vary significantly by uprate type (measurement uncertainty recapture is cheapest, extended uprates are most expensive), plant design, and the extent of modifications required, so the editable fields let you substitute project-specific values. Second, uprates are constrained by the physical limits of existing equipment (turbine, generator, cooling system capacity) and the safety margins built into the original plant design -- at some point, adding more capacity requires new construction rather than further uprating an existing unit. Data sources: NRC (Nuclear Regulatory Commission) power uprate approvals and technical documentation; historical uprate capacity additions from NRC and EIA (Energy Information Administration); uprate cost estimates from industry technical reports and EPRI (Electric Power Research Institute); turbine/generator upgrade costs from equipment manufacturers and industry case studies; new-build cost benchmarks from EIA and NREL (National Renewable Energy Laboratory). Verification: with defaults (1,100 MW, Stretch Power Uprate/7%, $2,000/kW uprate, $5,000/kW new-build), Additional Capacity from Uprate = 77 MW, Uprate Project Cost = $154,000,000, Equivalent New-Build Cost = $385,000,000, Cost Savings vs. New-Build = $231,000,000 (60%).