The EURATOM SOCRATES project investigates liquid source term phenomena in the context of severe nuclear power plant accidents, and develops innovative methods and computer models for liquid source term management.
The ‘liquid source term’ refers to the radioactive materials that are present in various liquid pathways, such as the containment sump, the cooling water, or the groundwater, during and after a severe nuclear power plant (NPP) accident. Interest in this topic has grown significantly since the Fukushima Daiichi NPP accident, due to the challenges of treating large volumes of contaminated water and understanding the behaviour of radionuclides in the water.
The EURATOM SOCRATES project (in 2024-2028) addresses critical gaps in understanding the liquid source term during severe nuclear accidents and provides innovative solutions to mitigate and monitor radionuclide releases into the environment. This is important for light water reactors of existing large nuclear power plants and for future small modular reactors (SMRs), which may be located near densely populated areas such as cities.
Objectives
By advancing scientific knowledge and technological capabilities, SOCRATES contributes to the mid- to long-term accident management for nuclear power plants, enhancing safety, environmental protection, safe waste management, and public wellbeing.
SOCRATES consists of three major parts:
- Reviewing current knowledge on liquid source term phenomena in the context of severe NPP accidents.
- Experimental research on the evolution of liquid phase chemistry, fuel debris leaching, innovative absorbent materials for radionuclides, and developing a miniature radiochemical laboratory.
- Defining key chemical processes for Cs, Sr and U in the liquid phase (e.g. containment sump) and developing mathematical models.
The SOCRATES work packages and their interrelatations are shown in Fig. 1.
Expected impacts
The unique contribution of SOCRATES will benefit nuclear safety and society via several outcomes:
- Comprehensive state-of-the-art report: SOCRATES will review the current understanding of the liquid source term in severe accidents, with emphasis on evaluating the capabilities of existing accident analysis codes (e.g. predicting chemical speciation in the liquid phase, both in soluble and insoluble forms). The report will establish a baseline and integrate the project results across all investigated areas.
- Experimental database: SOCRATES is developing a database on water chemistry during nuclear accidents by cataloguing potential materials (e.g. concrete, paint, metals) that could interact under different accident scenarios. Experiments will place major emphasis on investigating the behaviour of specific fission products, such as caesium (Cs) and strontium (Sr), in water, as well as fuel debris leaching, including tests with real corium samples. This database will support the development of computer models.
- New computer code models: SOCRATES will develop computer code models capable of predicting and managing the potential release of radioactive materials in liquid form during severe nuclear power plant accidents. The models will address various scenarios involving the behaviour of fission products in aqueous environments during severe accidents. Ultimately, the goal is to validate the developed models and integrate them into European safety analysis codes (e.g. ASTEC, AC2), supporting further accident management actions.
- Innovative absorbent materials: Mitigating the release of radioactive materials in liquid form during severe accidents requires innovative and effective clean-up technologies. Promising absorbents are being identified (e.g. zeolites, clays, MOFs, and silicas), and their performance will be demonstrated, including synthesis of the materials themselves.
- Innovative miniature radiochemical laboratory: A novel miniature radiochemical laboratory is being developed in SOCRATES to enable the early measurement of radionuclides of interest, such as Cs and Sr.
- Communication, dissemination, exploitation: In addition to the research activities, effective communication, dissemination, and exploitation of SOCRATES results is crucial. This includes, for example, the preparation of scientific publications and educational materials, as well as the organisation of a researcher mobility programme.
Partners
VTT, ASNR (former IRSN), CEA, Chalmers, CIEMAT, EDF, ETH, Framatome, GRS, JRC, KTH, KU, NUVIA, PSI, RUB PSS, SSTC NRS, UL.
End-User Group
If you would like to learn more about the SOCRATES project and follow its progress and results, please join the End-User Group by contacting socrates.eu@vtt.fi
This project has received funding from the HORIZON-EURATOM-2023-NRT-01 under grant
agreement No 101163745.
Please note, this article will also appear in the 25th edition of our quarterly publication.
