# Fact-checked content draft **Status:** English master copy for editorial review — not yet live **Evidence reviewed:** 16 July 2026 **Scope:** The case against treating **new nuclear power plants** as a priority climate solution, especially in Europe and North America. ## Proposed page introduction Nuclear power is a low-carbon source of electricity, and keeping an existing reactor running can be economical in some cases. That does not make every new reactor a good climate investment. New projects must also be judged by when they deliver, who carries their financial risk, how resilient their supply chains are, and how waste and security risks are managed. Here are seven evidence-based reasons not to treat new nuclear as the default solution. ## Proposed card copy ### 1. New reactors carry major cost and financing risk **Claim often made:** “Nuclear power is cheap.” Keeping an existing reactor running can be cost-competitive. Building a new one is a different decision: large reactors need high upfront capital, long financing periods and carry major overrun risk. The IPCC reports that first-of-a-kind projects in North America and Europe took more than 13 years and reached three to four times their initial budgets. Standardised East Asian builds have been faster, so the result is not universal. **Why this argues against new builds:** Scarce climate funds should favour options with more predictable delivery and financing risk. **Sources** - [IPCC AR6 WGIII, Chapter 6, section 6.4.2.4](https://www.ipcc.ch/report/ar6/wg3/chapter/chapter-6/) — regional construction times, overruns, high upfront investment and the explicit East Asian counterexample. - [IEA, *The Path to a New Era for Nuclear Energy* (2025), Executive Summary](https://www.iea.org/reports/the-path-to-a-new-era-for-nuclear-energy/executive-summary) — financing difficulty, government risk-sharing, and recent large-reactor project performance in the United States and France. - [IEA, *Nuclear Power and Secure Energy Transitions*, Executive Summary](https://www.iea.org/reports/nuclear-power-and-secure-energy-transitions/executive-summary) — why lifetime extensions of existing plants must be assessed separately from new construction. ### 2. Construction time is climate policy **Claim often made:** “New reactors are a quick climate fix.” A reactor avoids emissions only after it starts generating. Licensing, financing, construction and grid connection all come first, and first-of-a-kind projects are especially slow. The record differs by region: the IPCC reports five to six years for many recent East Asian builds, while first-of-a-kind projects in North America and Europe took more than 13 years. A project’s climate value therefore depends on when it begins displacing fossil generation, not only on its lifetime emissions. **Why this argues against new builds:** Where proven clean options can be deployed sooner, long lead times make new nuclear a weak near-term answer. Every year of delay means that other capacity must cover demand in the meantime. **Sources** - [IPCC AR6 WGIII, Chapter 6, section 6.4.2.4](https://www.ipcc.ch/report/ar6/wg3/chapter/chapter-6/) — construction records vary sharply by region and programme maturity. - [IEA, *The Path to a New Era for Nuclear Energy* (2025), Executive Summary](https://www.iea.org/reports/the-path-to-a-new-era-for-nuclear-energy/executive-summary) — long lead times and delivery risk; commercial first-of-a-kind SMR projects are expected around 2030. ### 3. High annual output does not remove fleet-wide outage risk **Claim often made:** “Baseload means nuclear power is always reliable.” Reactors often achieve high annual availability. But “always on” is not guaranteed: one defect can remove several large units at once. In 2022, stress-corrosion inspections, repairs and maintenance backlogs cut the French fleet’s average availability to 54%, versus 73% in 2015–2019. Cooling-water exposure varies by plant location and source. A resilient grid must be designed to replace these large, potentially correlated outages. **Why this argues against new builds:** A system dominated by similar large units must retain enough reserve, interconnection and replacement capacity for uncommon but consequential fleet events. **Fair context:** France had no supply disruption in 2022, and its nuclear availability later recovered. This example demonstrates correlated fleet risk, not permanent French unreliability. **Sources** - [RTE, *French Annual Electricity Review 2022*](https://analysesetdonnees.rte-france.com/en/electricity-review-keyfindings) — causes of the nuclear shortfall, 54% availability, the 2015–2019 comparison and the power system outcome. - [IAEA PRIS, world trend in energy availability factor](https://pris.iaea.org/pris/worldstatistics/worldtrendinenergyavailabilityfactor.aspx) — the high availability of the global fleet, which the card explicitly acknowledges. - [IAEA, climate resilience report](https://www-pub.iaea.org/MTCD/Publications/PDF/PAT-003_web.pdf), PDF pp. 6 and 9 — reported weather-related losses averaged 0.3% in 2022; exposure varies by plant location and cooling-water source. Figure 1 excludes Ukrainian units and depends on Member-State reporting. ### 4. Nuclear changes import dependence; it does not eliminate it **Claim often made:** “Nuclear power guarantees energy independence.” Uranium is compact and can be stockpiled, so its supply risk is not the same as imported gas. Yet nuclear power still depends on international chains for uranium, conversion, enrichment and fuel fabrication. In 2025, Russia supplied about 16% of uranium, 24% of conversion and 23% of enrichment services delivered to EU utilities. Nuclear can diversify energy supply, but it does not create automatic energy independence. **Why this argues against new builds:** Energy-security claims must include the full fuel chain, not only the reactor’s location. **Fair context:** At the end of 2025, EU utility inventories covered more than three reactor reloads on average. Canada was the EU’s largest uranium source, and most EU utilities had access to alternative fuel fabricators; VVER fuel remained a specific vulnerability. **Sources** - [Euratom Supply Agency, Market Observatory, 2025 data](https://euratom-supply.ec.europa.eu/activities/market-observatory_en) — uranium origin, conversion, enrichment, fuel-fabrication vulnerabilities and inventories. - [IEA, *The Path to a New Era for Nuclear Energy* (2025), Executive Summary](https://www.iea.org/reports/the-path-to-a-new-era-for-nuclear-energy/executive-summary) — concentration of global uranium and enrichment supply; Russia held about 40% of global enrichment capacity. ### 5. War creates nuclear-specific hazards **Claim often made:** “Civil nuclear power is insulated from geopolitical conflict.” Reactors are not nuclear bombs, and an attack does not automatically cause a meltdown. But war creates nuclear-specific hazards: damaged power lines, loss of cooling and electricity, restricted maintenance and pressure on staff. In its February 2026 report, the IAEA recorded two further total losses of off-site power at Zaporizhzhia. Enrichment and reprocessing also require strict safeguards because they are proliferation-sensitive technologies. **Why this argues against new builds:** Nuclear infrastructure creates long-lived security responsibilities that continue during shutdown, political instability and armed conflict. **Sources** - [IAEA, *Nuclear Safety, Security and Safeguards in Ukraine*, GOV/2026/7](https://www.iaea.org/sites/default/files/documents/gov2026-7.pdf), PDF p. 6, para. 14 — two total losses of off-site power at Zaporizhzhia on 6 and 13 December 2025. - [IAEA, *Technical Features to Enhance Proliferation Resistance of Nuclear Energy Systems* (2010)](https://www-pub.iaea.org/MTCD/Publications/PDF/Pub1464_web.pdf), section 2, printed p. 7 (PDF p. 17) — proliferation sensitivity of enrichment and civilian reprocessing facilities or technologies. - [IAEA, Safeguards and verification](https://www.iaea.org/topics/safeguards-and-verification) — how international safeguards verify that nuclear material remains in peaceful use. ### 6. A technical disposal concept is not an operating disposal system **Claim often made:** “The waste problem is already solved.” Deep geological disposal is the internationally recognised method for spent fuel and high-level waste. Saying there is no technical solution goes too far. The unresolved part is implementation: the IAEA’s 2024 roadmap recorded no operating repository for these wastes. In March 2026, Finland’s Posiva disposal facilities at Olkiluoto were still under operating-licence review. **Why this argues against new builds:** As of the cited 2024–2026 reports, new reactors would add waste before geological disposal for this waste category was operating. **Sources** - [IAEA, *Roadmap for Implementing a Geological Disposal Programme* (2024)](https://www-pub.iaea.org/MTCD/Publications/PDF/p15403-PUB2088_web.pdf), section 1.1, printed p. 2 (PDF p. 12) — confidence in geological disposal and the absence of an operating repository for high-level waste, including spent nuclear fuel, at publication. - [Finnish Radiation and Nuclear Safety Authority (STUK), 2026 national-report Q&A](https://stuk.fi/documents/150192312/154500381/Suomelle_esitetyt_kysymykset_ja_niiden_vastaukset_10_CNS.pdf), Article 19, ref. 125 (PDF p. 4) — Posiva’s facilities at Olkiluoto remained under operating-licence review in March 2026. - [U.S. NRC, *Backgrounder on Radioactive Waste*](https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/radwaste) — definitions and current management of spent reactor fuel and high-level waste. ### 7. SMRs are not yet a proven shortcut **Claim often made:** “Small modular reactors have solved nuclear power’s cost and speed problems.” Small modular reactors may lower the total investment per project, and units already operate in Russia and China. What is not yet proven is competitive, repeatable mass deployment. The economic case depends on standardised designs, factory production and many orders; smaller units can lose economies of scale. They may become useful, but they are not a proven shortcut for near-term decarbonisation. **Why this argues against new builds:** Policy should distinguish demonstrated performance from benefits that still depend on future scale, standardisation and cost reductions. **Sources** - [IPCC AR6 WGIII, Chapter 6, section 6.4.2.4](https://www.ipcc.ch/report/ar6/wg3/chapter/chapter-6/) — lower total investment but potentially higher cost per unit of generation. - [*IAEA Expands Global Initiative to Boost Knowledge of Small Modular Reactors* (4 August 2025)](https://www.iaea.org/newscenter/news/iaea-expands-global-initiative-to-boost-knowledge-of-small-modular-reactors) — units already operating in China and Russia. - [IEA, *The Path to a New Era for Nuclear Energy* (2025), Executive Summary](https://www.iea.org/reports/the-path-to-a-new-era-for-nuclear-energy/executive-summary) — the conditions and assumed cost reductions behind projected SMR deployment. ## Proposed transparency note > **Our position and method:** This site argues against treating new nuclear power plants as a priority climate strategy, especially in Europe. We do not dispute nuclear power’s low life-cycle emissions, and we recognise that continuing to operate an existing plant can make sense in some circumstances. Each card separates checkable evidence from our policy conclusion. We prefer direct sources, name the relevant place and period, and include material counterevidence. Corrections and better sources are welcome. ## Editorial rules for implementation - Keep **new construction**, **continued operation** and **lifetime extension** distinct. - Keep the factual paragraph separate from the “why this matters” conclusion. - Put two or three direct sources on each card; do not link to Semantic Scholar result pages. - Date all changing figures and name their geography. - Keep a fair counterpoint wherever it materially changes interpretation. - Use “low-carbon”, not “carbon-free”. - Do not compare nuclear thermal efficiency with wind or solar conversion efficiency. - Do not describe France’s 2022 reactor outages as mainly drought-related. - Do not cite WIPP as a repository for commercial spent reactor fuel or high-level waste. - Do not suggest that ordinary spent fuel can simply be turned into a nuclear bomb. - Do not claim that no SMRs operate, or that SMRs inherently recycle existing waste. - Add a visible “Report an error” link to the repository issue tracker when this copy goes live.