PASTELS · Project

Proven Passive Cooling Systems for Safer, Simpler Nuclear Reactors

energyTestedTRL 5

pastels-h2020.eu

Nuclear reactors need cooling systems that keep working even when the power goes out — think gravity-fed water tanks instead of electric pumps. Two promising passive technologies exist (called SACO and CWC), but Europe lacked the test data and simulation tools to prove they work reliably enough for licensing. This project ran full-scale experiments at test facilities in Germany and Finland, then used that real-world data to sharpen the computer models engineers rely on. The end result is a practical roadmap for getting these passive safety systems approved and installed in future European reactors, including smaller modular ones.

By the numbers

consortium partners

countries involved

total project deliverables

industrial partners in consortium

full-scale test facilities used (PKL and PASI)

The business problem

What needed solving

Europe's nuclear industry is moving toward passive safety systems that work without external power — critical for next-generation reactors and SMRs. But the simulation tools European engineers rely on were not validated for these specific technologies (SACO and CWC), creating a gap between what's already being deployed in non-European plants and what European regulators can approve. Without validated test data and proven computational methods, reactor designers face lengthy and uncertain licensing processes.

The solution

What was built

The project produced validated experimental datasets from full-scale tests at 2 major facilities (PKL in Germany and PASI in Finland), improved and benchmarked multiple European thermal-hydraulic simulation codes, developed code coupling methodologies for multi-scale analysis, and delivered a comprehensive licensing roadmap with methodology guidelines — 22 deliverables in total.

Audience

Who needs this

Nuclear reactor vendors designing SMRs with passive safety featuresNuclear utilities planning new builds or life extensionsNuclear safety consultancies performing thermal-hydraulic analysesNuclear regulators evaluating passive system safety casesPassive component manufacturers seeking validated performance data

Business applications

Who can put this to work

Nuclear Power Generation

enterprise

Target: Nuclear plant operators and reactor builders

If you are a nuclear utility or reactor vendor planning next-generation plants — this project generated full-scale experimental data and validated simulation tools for SACO and CWC passive safety systems. The methodology guidelines and licensing roadmap produced across 22 deliverables can cut years off your design validation cycle, especially for Small Modular Reactor programmes where passive cooling is a core selling point.

Nuclear Engineering & Consulting

mid-size

Target: Engineering firms providing safety analysis and licensing support

If you are a nuclear engineering consultancy that runs thermal-hydraulic safety analyses — this project benchmarked and improved multiple European system and CFD codes against real experimental data from 4 test facilities. The code coupling methodologies and benchmark results let you deliver more accurate safety cases to regulators, reducing review cycles and rework costs for your clients.

Nuclear Component Manufacturing

mid-size

Target: Manufacturers of passive safety components and heat exchangers

If you are a manufacturer of nuclear-grade heat exchangers or passive cooling components — this project produced detailed design reviews, scaling analyses, and performance data for SACO and CWC technologies tested at semi-industrial scale. The 2 documented facility configurations give you validated reference designs and performance benchmarks to accelerate your own product qualification.

Frequently asked

Quick answers

What would it cost to access the simulation tools and experimental data from this project?

The project produced methodology guidelines and benchmark datasets rather than commercial software. Access terms would need to be negotiated with the consortium led by Electricite de France. Since 4 industrial partners were involved, some results may be commercially restricted while others funded under EU rules should be publicly accessible.

Can these passive systems be deployed at industrial scale today?

The technologies were tested at semi-industrial full-scale facilities (PKL in Germany and PASI in Finland), which demonstrates physical feasibility. However, the project's own stated goal is a roadmap to achieving licensing and implementation — meaning regulatory approval for commercial deployment in European nuclear plants is still ahead.

Who owns the intellectual property and how can we license it?

IP is distributed across 11 consortium partners in 6 countries, led by Electricite de France. The consortium includes 4 industrial partners and 5 research organisations. Licensing arrangements would depend on which specific results you need — experimental data, simulation improvements, or design guidelines.

Is this relevant for Small Modular Reactors or only large plants?

The project explicitly targets Small Modular Reactors (SMRs). The objective states that given the growing use of SACO and CWC in non-European plants, it is essential for Europe's SMR future that simulation tools can handle these passive technologies accurately.

What regulatory pathway exists for these passive systems?

The project produced extensive methodology guidelines and a licensing roadmap specifically aimed at European nuclear regulators. These guidelines document the validated code coupling approaches and experimental evidence needed to support a safety case for passive systems in future plant designs.

How long until these results can be applied in real projects?

The project ran from 2020 to 2024 and is now closed, so all 22 deliverables including guidelines and the licensing roadmap are complete. Application timelines depend on individual reactor programmes and regulatory review processes, which typically take several years beyond the research phase.

Consortium

Who built it

The 11-partner consortium across 6 countries (Switzerland, Czech Republic, Germany, Finland, France, Italy) is led by Electricite de France — one of the world's largest nuclear utilities, which adds immediate industrial credibility. With 4 industrial partners, 5 research organisations, and 2 universities, the mix leans toward applied research rather than pure academia. The 36% industry ratio and zero SME involvement reflects the capital-intensive, highly regulated nature of nuclear technology. Notable is the geographic spread covering major European nuclear markets (France, Finland, Germany), which positions the results for broad regulatory acceptance across multiple national authorities.

ELECTRICITE DE FRANCECoordinator · FR
INSTITUT DE RADIOPROTECTION ET DE SURETE NUCLEAIREparticipant · FR
FRAMATOME GMBHparticipant · DE
COMMISSARIAT A L ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVESparticipant · FR
AGENZIA NAZIONALE PER LE NUOVE TECNOLOGIE, L'ENERGIA E LO SVILUPPO ECONOMICO SOSTENIBILEparticipant · IT
PNO Innovationparticipant · FR
PAUL SCHERRER INSTITUTparticipant · CH
UNIVERSITY OF STUTTGARTparticipant · DE
GESELLSCHAFT FUR ANLAGEN UND REAKTORSICHERHEIT (GRS) gGmbHparticipant · DE
UJV REZ ASparticipant · CZ
LAPPEENRANNAN-LAHDEN TEKNILLINEN YLIOPISTO LUTparticipant · FI

How to reach the team

Electricite de France (EDF), France — SciTransfer can facilitate an introduction to the project coordinator

Order a report on this consortium See ELECTRICITE DE FRANCE profile →

Next steps

Talk to the team behind this work.

Want to access PASTELS experimental data, simulation benchmarks, or the licensing roadmap for passive safety systems? SciTransfer can connect you directly with the right consortium partner for your specific need.

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