Multi-compartment THAI+ test facility, Becker Technologies GmbH.
In the wake of the OECD/NEA THAI project, conducted in three phases from 2007 until 2019, a new project, THAI Experiments on Mitigation measures, and source term issues to support analysis and further Improvement of Severe accident management measures (THEMIS) has been launched to follow up on outstanding questions in the area of combustion risks and iodine-aerosol behaviour in containment during a severe accident. Such outstanding questions, considering insights from the Fukushima-Daiichi accident analyses performed in the NEA BSAF project, have been identified through international efforts conducted under CSNI WGAMA, e.g. the status report on hydrogen management and related computer codes and the workshop on source term. THEMIS addresses issues relating to combustion risk in ex-vessel phases of a severe accident with H2/CO mix, the presence of fine aerosols, the evolution of airborne iodine oxides, the retention of fission products under pool scrubbing conditions and radionucleides remobilisation phenomena. They have been identified to require additional research. With regards to the radionucleides remobilisation phenomena, THEMIS investigations are complementary to the NEA ESTER project.
THEMIS experiments are highly relevant to the improvement and validation of thermalhydraulic and severe accident codes and their use, in particular for the assessment of phenomena which can threaten the containment integrity and can affect radioactive release and of the efficiency of related mitigation systems, as well as maintaining competence and expertise in this field.
Belgium, Canada, China, Finland, France, Germany, Japan, Korea, Russia, Slovak Republic, Spain, Sweden, Switzerland, United Kingdom
November 2020 to April 2024
EUR 5.05 million