Executive Summary

Four decades after Chernobyl, nuclear power is undergoing political and technological reassessment. Facing rising energy prices, climate change, and energy security risks (exemplified by the blockade of the Strait of Hormuz), new reactor concepts are coming into focus – particularly Small Modular Reactors (SMR) of the third generation and experimental fourth-generation reactors cooled by liquid sodium instead of water. Twenty countries plan to triple their nuclear power capacity by 2050. The first European SMR facilities could come online in the 2030s.

People

Topics

  • Small Modular Reactors (SMR)
  • Fourth-generation reactors
  • Nuclear waste and final storage
  • Energy security and geopolitics
  • Nuclear fuel enrichment and proliferation

Clarus Lead

Why reassessment is happening now: The Iran conflict and the blockade of the Strait of Hormuz (20% of global oil demand) have re-established energy security as a political priority – parallel to the climate crisis, which demands CO₂-free baseload power. EU Commission President Ursula von der Leyen publicly called Europe's exit from nuclear power a "strategic mistake." This paradigm shift creates space for smaller, decentralized reactor models that are less daunting to investors than megaprojects like Finland's EPR (€11–20 billion).

Relevance for decision-making: For countries like Switzerland, Lithuania, and Eastern Europe, SMR could provide a niche solution for grid stabilization – without dependence on Russian fuel processing. At the same time, new proliferation risks and unresolved economic viability questions emerge that could delay investment decisions.

Detailed Summary

Technological paradigm shift: Nuclear reactors of the 1970s–1980s competed with coal and gas power plants through "economy of scale" – ever-larger facilities for lower costs. Today, the energy context is fragmented: volatile renewable sources (wind, solar) decentralize electricity production and require flexible backup capacity. SMR with 300 megawatts – roughly one-third of a conventional reactor (Gösgen: ~1000 MW) – can be flexibly switched on and off and require initial investments of around $4 billion instead of $12–20 billion.

The Canadian project at Darlington (GE-Vernova Hitachi, online 2030) uses passive cooling – a safety feature that could have prevented the Fukushima disaster. In case of power outages, cooling functions without external power supply. Technically, this is according to Pautz "no rocket science," but rather proven engineering practice.

Fourth generation and nuclear waste problem: Sodium-cooled reactors (Bill Gates' TerraPower project in Wyoming) operate at higher temperatures and require no pressure for heat control. Crucial: they can use fast neutrons not only to split uranium-235, but also plutonium and long-lived radionuclides. This reduces storage duration from >100,000 years to possibly 100–10,000 years. In Switzerland, approximately 1,500 cubic meters of nuclear waste have been produced in 60 years – enough to fill two single-family homes.

Critical challenges: Sodium is highly reactive (contact with water/air leads to fires). TerraPower requires 5–20% enriched uranium, while current reactors use 3–5% – closer to weapons-grade material. This increases proliferation risk. A single 300-MW module produces no less waste than a large reactor; five SMR are equivalent to one 1,500-MW reactor. Economic viability remains unclear: SMR could be more expensive per kilowatt-hour than wind/solar, but find a niche in grid stabilization and heat supply (hydrogen production, industrial processes).

Fuel and European sovereignty: Many European fuel rods come from Russia – a dependency that becomes critical after the Ukraine war. The US and Europe must develop capabilities for their own fuel rod manufacturing; Russia has decades of experience. This requires time and investment.

Key Findings

  • Energy security as turning point: Geopolitical crises (Iran, Strait of Hormuz) and climate change have reclassified nuclear power from a risk technology to a strategic option.

  • SMR as decentralization model: Smaller, modularly deployable reactors fit with volatile renewable power sources and reduce investment risks – ideal for small countries and industries with continuous power demand (data centers, hydrogen production).

  • Fourth generation partially solves the nuclear waste problem: Sodium-cooled or other exotic reactors can utilize long-lived radionuclides, significantly reduce storage durations – but remain technologically immature and expensive.

  • Proliferation and fuel dependence are newly assessed risks: Higher enrichment levels and Russian market share in fuel processing create geopolitical vulnerabilities.

Critical Questions

  1. Evidence/Data quality: Which cost calculations for SMR are based on realized projects versus manufacturer forecasts? (The EPR case demonstrates systematic optimism bias.)

  2. Conflicts of interest: To what extent do the business interests of GE, Hitachi, and TerraPower influence regulators' safety assessments – particularly regarding proliferation risk from 5–20% enriched uranium?

  3. Causality/Alternatives: Cannot the grid stabilization problem be solved more cheaply through massive battery storage, flexible gas power plants, and demand-side management without introducing new proliferation risks?

  4. Feasibility: How realistic is the 2030s online-date in Canada given regulatory approval processes and global supply chain disruptions?

  5. Final storage concretely: Finland is building a final repository; Switzerland is planning. How likely is it that a five-fold increase in reactors (SMR scenario) leads to political delays in finalizing final storage?

  6. Fuel sovereignty: What investments and timeframes are required for Europe to independently manufacture fuel rods from Russia – and who bears these costs?

  7. Sodium safety in urban context: How is the fire risk of sodium-cooled reactors in densely populated countries handled in regulatory terms? Are there different standards?

  8. Economic transparency: Are SMR electricity generation costs (including final storage, insurance, decommissioning) compared with wind/solar under identical financing conditions, or do SMR benefit from hidden subsidies?

Further Reports

  • Finland nuclear waste repository: Construction of Europe's first deep repository for highly radioactive waste underway; Switzerland follows with designated sites (timeline: 2030s).

Source Directory

Primary source:

Quantum Leap Podcast (NZZ Science Desk) – "Nuclear Energy Renaissance: Small Modular Reactors and Fourth-Generation Reactors" Moderation: Lena Waltle, Christian Speicher Guests: Andreas Pautz (Paul Scherrer Institute), Annalisa Manera (ETH Zurich) Publication: 25.04.2026 URL: https://audio.podigee-cdn.net/2466283-m-67d26fc1a07eeb1c5acbf0d0d4417de5.mp3?source=feed

Supplementary contexts (mentioned in transcript):

  • Darlington Project (GE-Vernova Hitachi, Canada, 2030)
  • TerraPower Project (Wyoming, sodium-cooled, Bill Gates)
  • EPR Flamanville/Finland (cost example: €11–20 billion)
  • Finnish final repository Onkalo
  • Swiss final repository planning

Verification Status: ✓ 25.04.2026

This text was created with the support of an AI model. Editorial responsibility: clarus.news | Fact-checking: 25.04.2026