Led by the French Alternative Energies and Atomic Energy Commission (CEA), the TCOFF-2 initiative aims to enhance expertise and knowledge dissemination in thermodynamics modelling applied to materials science. Its objectives include improving the management of thermodynamic data's impact, including validation, uncertainty propagation, and sensitivity analysis, within severe accident codes. This endeavour will offer training opportunities for current engineers and researchers in data manipulation and the application of thermodynamic calculations specific to accident scenarios. Furthermore, it seeks to facilitate knowledge exchange and raise awareness within the scientific community regarding the dearth of fundamental data concerning severe accidents and their repercussions.

Background

The TCOFF-2 joint project aims to improve the models describing the materials interactions and the role they play in the various phases of the severe accidents, the ultimate goal being the integration of such models in severe accident simulation codes to increase their accuracy.

This improvement will be driven in particular by state-of-the-art knowledge of the thermodynamic properties of the material systems relevant to the description of core materials degrading through a severe accident sequence. Such knowledge, partially developed and accumulated during the execution of the first phase of the TCOFF (TCOFF-1) project and previous international efforts, will be systematised and further extended in this second phase of TCOFF (TCOFF-2) through joint experts’ evaluations, thermodynamic modelling, and focused R&D efforts.

The project focuses on the accident sequence going from the early stages of the fuel degradation, through the fuel relocation, the molten pool formation, reactor pressure vessel (RPV) failure, and the interaction between the corium and the concrete. The project will also address the fission products (FPs) behaviour, their distribution in the various phases forming during the accident and the source term evaluation.

Objectives

The main objectives of the TCOFF-2 NEST project are:

1. to strengthen training and knowledge transfer in the field of thermodynamics modelling applied to materials science;
2. to ensure better control of the impact of thermodynamic information (data validation, propagation of uncertainties, sensitivity analysis) in severe accident codes.

This project will provide training for current engineers and researchers in data handling and the use of thermodynamic calculations dedicated to accidental scenarios. For younger people, it will enable them to take advantage of the current momentum and renewal in the nuclear field to develop the skills of new generations of professionals. More broadly, this transfer of knowledge will also raise awareness throughout the scientific community of the lack of fundamental data in the field of severe accidents and their consequences.

Leading Organisation

• Alternative Energies and Atomic Energy Commission (CEA), France 

Participating Organisations

• Canadian Nuclear Laboratories, Canada
• McMaster University, Canada
• Karlsruhe Institute of Technology, Germany
• Japan Atomic Energy Authority (JAEA), Japan
• Science Tokyo, Japan
• Swedish Radiation Safety Authority (SSM) , Sweden (non-NEST member)
• KTH Royal Institute of Technology, Sweden (non-NEST member)

Fellows

2024

• Morgan Collins, McMaster University, Canada
• Paul Abinson, Stuttgart University, Germany
• Umme Mahbuba Nabila, University of Michigan, United States
• Hong Fatt Chong, Science Tokyo, Japan
• Yuya Nakagawa, Waseda University, Japan
• Ryu Yano, Osaka Univesity, Japan

2025-26 Call for Fellowships

Applications for 2025-26 NEST TCOFF-2 fellowships are open until 1 June 2025. Applicants are requested to select one of the following fellowship programmes:

• Karlsruhe Institute of Technology (KIT), Institute for Applied Materials IAM-AWP, Germany, “Experiments on high-temperature oxidation and degradation of ATF cladding materials”, 3-12 months duration, supervised by Dr Martin Steinbrück
• Kungliga Tekniska Högskolan (KTH), Division of Nuclear Power Safety, Sweden, “Thermodynamic modelling of the corium systems included in SIRT (System Identification and Ranking Table)”, 6-12 months duration, supervised by Dr Andrei Komlev
• Kungliga Tekniska Högskolan (KTH), Department of Chemistry (Nuclear Chemistry group), Sweden, “Radiation induced dissolution of model corium”, 6-12 months duration, supervised by Prof. Mats Jonsson
• Commissariat à l’energie atomique et aux energies alternatives (CEA), Cadarache Research Center, IRESNE Institute, DTN, SMTA, Severe accident experimental laboratory, France, “Experimental support to thermodynamic calculations for severe accident studies and/or accident tolerant fuel”, 3-12 months duration, supervised by Drs Jules Delacroix, Pascal Piluso, Andrea Bachrata

For more details on the proposed fellowships, please refer to the information sheet. 

How to apply 

Applicants should send the application form (with a CV and a motivation letter (max. one page)) to Daniel Shepherd: daniel.shepherd@oecd-nea.org. Accompanying letters of recommendation will also help to support the application.

The selection will be made based on the adequacy of the scientific profile and interests of the candidates with the proposed fellowship. The receiving organisation and TCOFF2/NEST Core Group will conduct interviews as needed and propose their selection to the TCOFF-2 project and the decision will be endorsed by the TCOFF-2 Management Board.

Please note that applicants must be affialiated with an organisation or university situated in a NEST country. 

Three students will be financially supported by this programme (max. 7 500 Euro/person) for the transportation and accommodation. Successful applicants will be notified by 1 July 2025.