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Advancing Nuclear Energy

This interactive tool from The Breakthrough Institute brings together two distinct analyses of nuclear energy in the United States. The Map and Dashboard tabs visualize results from a 2022 modeling study of advanced nuclear deployment through 2050. The Uprate tab is a separate, independently-sourced analysis of the existing US nuclear fleet's near-term uprate and restart potential, built from current NRC and industry data.

Geographic scope: This tool covers the contiguous 48 states only. Alaska and Hawaii are not shown — neither state has operating or historical nuclear power plants, and both were outside the scope of the underlying modeling study.

Part 1 — Modeling Scenarios (Map & Dashboard)

This interactive map visualizes results from the Advancing Nuclear Energy report (2022) by The Breakthrough Institute, which uses high-resolution nationwide modeling to evaluate how advanced nuclear reactors could play a major role in a least-cost plan to transition the US power grid entirely to clean energy by 2050.

This study modeled the evolution of the US power grid over the next three decades using the Weather-Informed energy Systems: for design, operations and markets-Planning Version (WIS:dom-P®) optimization model, developed by Vibrant Clean Energy, LLC (VCE®).

Map Tab

Each circle represents a power plant location. Circle size corresponds to installed capacity (MW) and color indicates the dominant generation technology. Use the year slider (2020–2050) and scenario tabs to explore how the grid evolves under different assumptions. Site conversion markers (teal diamonds) indicate existing power plant sites — coal, natural gas, or nuclear — where the model builds new advanced nuclear capacity, reusing existing transmission, cooling, and grid infrastructure. On average, fossil plant conversions occur roughly 16 years after the original plant retires. Hover over any state for a summary; double-click to jump to that state's Dashboard profile.

The Four Scenarios

The study uses a bounding analysis with four scenarios that vary two key uncertainties about advanced nuclear technology:

• Cost — First-of-a-kind (FOAK) capital costs, set at "Low" or "High" bounds based on published estimates.
• Learning Rate (LR) — The rate at which costs decline as more reactors are deployed. "Low LR" = 5% cost reduction per doubling of capacity (similar to coal historically). "High LR" = 12% (similar to wind power).

Across all four scenarios, the model independently chooses to deploy large amounts of advanced nuclear, indicating these technologies provide high value to the electricity system even under conservative assumptions.

Technologies on the Map

Nuclear

Other Technologies

Key Findings

• Advanced nuclear reaches 190 to 470 GWe of deployed capacity by 2050, supplying 20–48% of US electricity generation.
• Cumulative capital investment in advanced nuclear grows to $830 billion to $1.1 trillion by 2050.
• Advanced nuclear creates 74,000 to 223,000 permanent operations jobs by 2050.
• The model converts 109–153 GWe of coal capacity (52–73% of today's coal fleet) to advanced nuclear sites.

Dashboard Tab

• State Explorer — Select any state to see an auto-generated summary, energy mix donut chart, capacity over time, and combined advanced nuclear statistics (reactors, jobs, revenue, and ROI). Double-click a state on the map to jump directly here.
• National Summary — Nine charts covering additional advanced nuclear capacity with policy goal benchmarks, nuclear jobs, nuclear share of capacity and energy, installed capacity by technology, retail electricity rates, total system cost, a summer week dispatch profile, and CO₂ emissions trajectory across all scenarios.

Map Overlays: Policy Climate & Electricity Market

Two optional overlays (available on the Map tab) provide policy and market context for each state:

Policy Climate indicates whether a state has active legislation restricting new nuclear construction:

• Permissive — No statutory restrictions on new nuclear power plant construction.
• Mixed — Some conditions or partial restrictions apply (e.g. voter approval requirements or waste storage conditions).
• Restricted — State law prohibits approval or construction of new nuclear power plants until specific conditions are met (e.g. federal waste disposal solution). Source: National Conference of State Legislatures (NCSL).

Electricity Market Structure indicates how power generators recover their costs:

• Merchant Generator — The state has a deregulated wholesale electricity market (typically run by an RTO such as PJM, MISO, or ERCOT). Generators compete and sell power at market prices with no guaranteed cost recovery. New nuclear development in these states requires private financing, long-term power purchase agreements (PPAs), or direct corporate offtake (e.g. Microsoft–Constellation at Three Mile Island). Higher merchant risk makes new construction more challenging without policy support.
• Cost Recovery — The state operates under traditional rate-of-return regulation. A vertically integrated utility holds a monopoly franchise and recovers prudently incurred costs—including construction costs—through regulated customer rates approved by a state public utility commission. This structure lowers financing risk for capital-intensive projects like nuclear, as seen with Georgia Power’s Vogtle Units 3 & 4. Source: Electric Choice.

Post-publication adjustments to conventional nuclear fleet: Several plants have been corrected or added on top of the original 2022 report data to better reflect operating reality. Palisades (Michigan), Three Mile Island Unit 1 / Crane Clean Energy Center (Pennsylvania), and Duane Arnold (Iowa) were shut down after the model was finalized and are shown as restarting; they are not reflected in the scenario projections. Three plants were retired early or omitted by the WIS:dom-P economic optimization and have been reinstated: Ginna (New York, fully merchant since 2017, absent from model), Limerick (Pennsylvania, model retired early 2025; license runs to ~2049), and Davis-Besse (Ohio, model retired early 2025; license runs to 2037). Restart status for all plants follows NRC reactor status records and publicly announced restart timelines.

Part 2 — Nuclear Uprate Analysis (Uprate Tab)

The Uprate tab is based on current industry and regulatory data.

History of Nuclear Power Uprates

Power uprates — NRC-approved increases to a reactor’s licensed thermal output — have added approximately 7,540 MWe to the U.S. nuclear fleet since the 1970s, equivalent to roughly seven large reactors built at a fraction of the cost and time. The NRC recognizes three categories:

• Measurement Uncertainty Recapture (MUR) — typically <2%; uses improved flow instrumentation to recover conservatism already built into the license. ~6-month NRC review.
• Stretch Power Uprate (SPU) — 2–7%; operates within existing safety margins without major hardware changes. ~9-month review.
• Extended Power Uprate (EPU) — up to ~20%; requires feedwater, turbine, and/or safety system modifications. ~12-month review.

• 1977–1990s — Early uprates were primarily instrumentation improvements (proto-MUR); total additions modest.
• 1998–2012 — Major EPU wave: the NRC approved uprates at more than 50 reactors, adding roughly 6,000 MWe. GE BWRs — which have up to 20% headroom — led adoption; Westinghouse PWRs followed with tighter margins (~9%). All historical NRC approvals are documented in the NRC approved uprate applications database.
• 2012–2021 — Slowdown. Low natural gas prices compressed wholesale electricity prices, reducing the return on capital-intensive uprate investments. Few new EPU applications were filed.
• 2022 — The Inflation Reduction Act established a nuclear production tax credit (~$15/MWh), restoring the economics of existing-fleet investments including uprates.
• 2023–2024 — DOE launches the UPRISE initiative (Uprate and Restart Initiative Supporting the Existing fleet), funding feasibility studies at nine sites. Target: 2,500 MWe by 2027 and 5,000 MWe by 2029.
• 2025–2032 — The NRC’s published pipeline includes 32 applications through 2032, totaling ~2,422 MWe of expected approvals. The broader industry target extends to ~8,000 MWe per a 2025 NEI survey (which includes restarts and fuel-cycle extensions in addition to thermal uprates).

What the Uprate Tab Shows

A static 2025 snapshot of all operating US nuclear plant sites, showing three types of potential capacity additions:

• Uprate headroom (dashed amber ring) — Remaining thermal power uprate capacity based on reactor type caps (e.g. 20% for GE BWRs, 9% for Westinghouse 4-loop PWRs). Derived from NRC-verified current licensed power levels and INL uprate analysis.
• EPU planned (dashed green ring) — Plants with an Extended Power Uprate (EPU) application expected at the NRC, per the NRC's published pipeline of upcoming applications.
• Restart plants (teal dot) — Recently retired plants with publicly announced restart plans: Palisades (MI), Crane Clean Energy Center / TMI Unit 1 (PA), and Duane Arnold (IA).

Click any ring or dot on the map for plant-level details including per-unit thermal capacity, completed uprates, and remaining headroom. The right panel shows national totals and a timeline of cumulative NRC-approved uprate capacity vs. the DOE UPRISE capacity addition targets (NRC approvals are used as a leading indicator; actual capacity additions follow approval).

Data Sources (Uprate Tab)

• Uprate headroom: FAI State Permitting Playbook (Nov 2025), cross-verified with NRC approved uprate applications and INL/RPT-24-78810 (June 2024).
• NRC pipeline: NRC Expected Applications for Power Uprates (retrieved May 2026).
• Restart plants: NRC reactor status records and publicly announced restart timelines.

Uprate potential is expressed in MWe (electrical) estimated as MWt ÷ 3, assuming ~33% thermal efficiency per DOE/INL methodology. The DOE UPRISE initiative aims to achieve 2,500 MWe of additional nuclear capacity by 2027 and 5,000 MWe of total additional nuclear capacity by 2029.

Citation: Stein, A., Messinger, J., Wang, S., Lloyd, J., McBride, J., Franovich, R. (2022). Advancing Nuclear Energy: Evaluating Deployment, Investment, and Impact in America's Clean Energy Future. The Breakthrough Institute.
Modeling by Vibrant Clean Energy (VCE) using WIS:dom-P®.
Regulatory climate data: National Conference of State Legislatures (NCSL).
Electricity market structure: Electric Choice.
Nuclear uprate data: FAI State Permitting Playbook (Nov 2025); INL/RPT-24-78810 (June 2024); NRC approved uprate applications; NRC Expected Applications for Power Uprates (May 2026); DOE UPRISE initiative.

Nuclear Share of Total Energy chart — capacity factor assumptions: The WIS:dom-P model reports installed capacity (MW) rather than annual generation (GWh). Energy shares are estimated as capacity × capacity factor × 8,760 hr/yr. Assumed capacity factors: Nuclear / SMR / ARTES / HTGR 90%; Natural Gas CC 50%; CCS 50%; Coal 40%; Hydro 40%; Geo/Bio 80%; Offshore Wind 45%; Onshore Wind 35%; Utility-Scale Solar 22%; Rooftop Solar 15%; Storage 0% (storage is excluded as it does not represent net generation).