Six projects show a wide range of nuclear construction results. European and US first-of-a-kind projects ran far beyond their early schedules, while standardised programmes in Asia and the UAE performed better. The records do not support one universal build-time or cost claim.
Evidence reviewed
Translation status
Master text
Revision
2026-07-17.2
The strongest pattern is conditional: mature designs, repeat construction and experienced supply chains improve delivery. Financing structure and cost boundaries still make simple rankings unreliable.
Schedule record
The chart compares the earliest stated operating target with actual commercial operation, or the current target where construction continues.
The initial estimate was about EUR 3.3 billion, with no clear price basis in the summary evidence. EDF's current construction estimate is EUR 13.2 billion in 2015 prices, excluding construction interest. In 2020 the French Court of Accounts estimated EUR 19.1 billion in 2015 prices on a wider basis that included financing, but used a completion assumption that is now outdated. The figures measure different boundaries.
The original fixed-price turnkey contract was about EUR 3 billion. TVO estimated its total investment at EUR 5.5 billion in 2018; no final owner outturn has been published. Supplier losses must not simply be added to owner cost.
For Georgia Power's 45.7% share, USD 4.418 billion of capital was certified in 2009. The current figure is about USD 10.7 billion of net capital after guarantees and refunds, plus about USD 3.53 billion of financing. There is no official consolidated final total for all owners, so this share should not be scaled up.
EDF's estimate rose from GBP 18.1 billion to GBP 35 billion, both in 2015 pounds. Older EDF definitions excluded construction interest and foreign-exchange effects; the latest short update does not restate the full boundary. EDF says another twelve months would add about GBP 1 billion in 2015 pounds.
The original KEPCO contract was reported at about KRW 20 trillion, but its price basis and exact scope are unclear and no official final outturn is available. A USD 2.42 billion figure reported in 2023 concerns refinancing, not construction cost.
No official consolidated initial and final cost with a clear price year and scope is available. A precise overrun percentage would therefore imply more certainty than the evidence supports.
Dates use official construction-start and commercial-operation definitions where available. A grid connection is not treated as commercial operation.
Original and current costs are compared only when their price year, project scope, unit count and treatment of financing are sufficiently clear.
Owner cost, supplier loss, overnight construction cost and full financing cost are different measures. They are not merged into one headline figure.
Each case includes the strongest fair interpretation, including evidence that supports successful nuclear delivery.
Case notes
Cost statements below keep nominal and real prices, financing and ownership shares separate. Unknown values remain unknown.
France
Flamanville 3
1 × EPR · 1 630 MW
Construction start
3 Dec 2007
Current or actual
Construction began in December 2007. Operation was initially expected in 2012. First grid connection followed in December 2024 and full power in December 2025. PRIS still records no commercial-operation date.
Cost evidence
The initial estimate was about EUR 3.3 billion, with no clear price basis in the summary evidence. EDF's current construction estimate is EUR 13.2 billion in 2015 prices, excluding construction interest. In 2020 the French Court of Accounts estimated EUR 19.1 billion in 2015 prices on a wider basis that included financing, but used a completion assumption that is now outdated. The figures measure different boundaries.
Financing and risk
EDF carried the project on its balance sheet. Its state-controlled ownership ultimately leaves a substantial share of construction and financing risk with the company and its public shareholder.
Construction began in August 2005. Commercial operation was expected by the end of April 2009 and began in May 2023. Final handover to TVO followed in June 2025.
Cost evidence
The original fixed-price turnkey contract was about EUR 3 billion. TVO estimated its total investment at EUR 5.5 billion in 2018; no final owner outturn has been published. Supplier losses must not simply be added to owner cost.
Financing and risk
TVO financed its owner obligations through the Finnish Mankala model. A fixed-price turnkey contract transferred much of the construction overrun risk to the Areva-Siemens supplier consortium, followed by arbitration and settlement.
Nuclear construction began in 2013. The units were then expected around 2016 and 2017; commercial operation began in July 2023 and April 2024.
Cost evidence
For Georgia Power's 45.7% share, USD 4.418 billion of capital was certified in 2009. The current figure is about USD 10.7 billion of net capital after guarantees and refunds, plus about USD 3.53 billion of financing. There is no official consolidated final total for all owners, so this share should not be scaled up.
Financing and risk
The project combined utility investment, regulated cost recovery and up to USD 12 billion in US federal loan guarantees. Westinghouse's bankruptcy moved further completion risk to the owners, with important consequences for customers and shareholders.
Formal nuclear construction began in December 2018. The original programme targeted Unit 1 for the end of 2025. EDF now forecasts 2030. This remains a forecast, not an operating result.
Cost evidence
EDF's estimate rose from GBP 18.1 billion to GBP 35 billion, both in 2015 pounds. Older EDF definitions excluded construction interest and foreign-exchange effects; the latest short update does not restate the full boundary. EDF says another twelve months would add about GBP 1 billion in 2015 pounds.
Financing and risk
EDF and CGN finance construction. A 35-year, inflation-linked Contract for Difference supports revenue after generation begins, alongside a UK guarantee. The developer carries construction risk, while consumers carry part of the long-term price risk through the contract.
Construction of the four APR-1400 units began between 2012 and 2015. They entered commercial operation from April 2021 to September 2024, after roughly nine construction years per unit.
Cost evidence
The original KEPCO contract was reported at about KRW 20 trillion, but its price basis and exact scope are unclear and no official final outturn is available. A USD 2.42 billion figure reported in 2023 concerns refinancing, not construction cost.
Financing and risk
ENEC owns 82% and KEPCO 18%. Financing initially used Korean export credit and later UAE banks. This lowered financing uncertainty but kept risks within government-supported institutions.
Construction began in 2009 and 2010. Commercial operation followed in December 2018 and September 2019. Public early targets for 2013 and 2014 could not be verified well enough in accessible primary sources and are therefore not used as schedule data.
Cost evidence
No official consolidated initial and final cost with a clear price year and scope is available. A precise overrun percentage would therefore imply more certainty than the evidence supports.
Financing and risk
The project was delivered by a joint venture led by the state-controlled CGN group, with EDF and a regional Chinese partner. State-linked ownership and an established Chinese construction programme shaped its financing and delivery environment.