This project has received funding from the European Union's Horizon 2020 research and innovation programme under agreement No 945275

The PASTELS project will demonstrate how innovative passive safety systems can support modernisation and optimisation of the European nuclear industry by providing relevant new safety options. The overall objective of the project is to improve the ability of European nuclear actors to design and deliver innovative passive safety systems - which are particularly promising as they do not rely on power supply or human intervention - and simulate their behaviour to support the safety demonstration.

PASTELS will make significant progress in the study of two specific passive systems, the Containment Wall Condenser (CWC) and the Safety Condenser (SACO) by:

  • Building on and leveraging existing available computational codes to simulate the relevant thermal-hydraulic phenomena,
  • Developing a robust, validated, multi-scale simulation methodology of passive systems,
  • Performing new experimental studies to obtain the relevant validation data.

The project will deliver extensive methodology guidelines as well as a roadmap to achieving the licensing and implementation of these innovative passive system technologies in future European Nuclear Power Plants (NPPs).
The PASTELS project has obtained the NUGENIA label on 23/09/2019 (Certificate number: 2019NUG0076 - NUGENIA - SNETP).

PASTELS concept

PASTELS specific objectives and outputs

Obtain experimental data from a scaled-down SAfety-COndenser (SACO) which will permit the validation of calculation models and correlations for condensation phenomena as well as for the integral system behaviour for the removal of residual decay heat. This will be achieved through the construction and operation of a SACO at the Primärkreislauf-Versuchsanlage (primary coolant loop test facility PKL) test facility owned and operated by Framatome GmbH in Erlangen, Germany.

Identify physical mechanisms that could reduce the heat transfer efficiency of a Containment Wall Condenser (CWC) and use the experimental data obtained to support computational code validation. This will be achieved through the adaptation and operation of a CWC at the Passive heat removal system (PASI) test facility at LUT University in Finland.

  • Corresponding PASTELS outputs: Extensive experimental data covering multiple scenarios.

Assess and improve several European simulation tools with the addition of new and independent experimental data allowing the reduction of key uncertainties, on the basis of the different types of experiments.

  • Corresponding PASTELS outputs: Improved numerical tools, namely the German system code package AC², the French thermo-hydraulic system code CATHARE, the French Computational Fluid Dynamics (CFD) code NEPTUNE_CFD and the French integral severe accident code ASTEC.

Collect knowledge on the physical behaviour of SACO and CWC in operation as observed during the experimental activities. This knowledge will provide key design recommendations.

  • Corresponding PASTELS outputs: Design guidelines for SACO and CWC implementation.

Define methodologies and guidelines on the validation and use of numerical tools for innovative passive system modelling and simulation and prepare a roadmap to bring SACO and CWC to European industrial readiness.

  • Corresponding PASTELS outputs: Methodologies and guidelines for validation and use of numerical tools for innovative passive systems and Roadmap for European versions of SACO and CWC.