The key objective of the STEP-SMR project is to enhance the reliability and predictive capability of severe accident (SA) safety analyses for light water-cooled Small Modular Reactors (LW-SMRs). Experimental data generated within the project will be provided under the specific conditions of SMR severe accidents, not available in the high-quality international databases. A systematic validation programme will be defined to extend the predictive capability of state-of-the-art computational SA tools across representative accident scenarios and mitigation measures relevant to SMR designs. Possible extensions/refinements of physical and chemistry models implemented in severe accident analysis codes will be identified based on comparison between experimental data and modelling

• To address the major critical gaps needed to be able to make a sound safety analysis of LW-SMR, thereby promoting the application on LW-SMRs in Europe and enabling their application beyond power production
• The data and models resulting from the STEP-SMR project will enable assessing the mitigation methods, including uncertainties, and thereby determining necessary safety measures which are reasonably practicable and sufficient to ensure safe and societally acceptable operation of the reactors.

• Review LW-SMR designs relevant for Europe in the short and medium term for their severe accident response
• Experiments at ambitious conditions to address the major data gaps for relevant designs
• Mitigation of source term – validate the data for source term mitigation for LW-SMRs
• Assessment of modelling uncertainties
• To assess the possibility for practical elimination of need for off-site measures in case of an accident in LW-SMRs

PSI, Switzerland / ASNR, France / Becker Technologies, Germany / CIEMAT, Spain / FZJ, Germany / LEI, Lithuania / UJV REZ, Czech Republic / VTT, Finland / SSTC NRS, Ukraina / NRG PALLAS, The Netherlands / CVR, Czech Republic / JRC Petten

Project coordinator:

Terttaliisa Lind (Terttaliisa.lind@psi.ch)