Experiments on Source Term for Delayed Releases (ESTER) Project
Joint project

Following several years of experimental research in the field of source terms analysis in the BIP, STEM and THAI joint projects but also other activities, the NEA Working Group on the Analysis and Management of Accidents (WGAMA) organised in January 2019 a Source Term Workshop to discuss the achievements in this area and to identify research priorities for future projects. The outcome of the workshop served as basis for the French Institute for Radiological Protection and Nuclear Safety (IRSN) to propose together with their partner, the French Alternative Energies and Atomic Energy Commission (CEA), and the interested community the Experiments on Source Term for Delayed Releases (ESTER) project.

The experiments in ESTER will focus on two of the four identified thematic areas of the workshop. As first topic, the investigations will address remobilisation of fission product deposits that might occur during a severe nuclear accident and contribute to delayed releases. There will be separate effect tests, semi integral tests for studying coupled effects in the CHIP facility at IRSN as well as confirmatory tests on real fuel samples in the VERDON facility at CEA. As second topic, the ESTER project tries to achieve an improved understanding of the processes involved in the formation of organic Iodines in the containment. The related experiments continue the work done during the STEM Joint Projects and will be conducted in the EPICUR facility at IRSN. The investigations in ESTER will be complemented by the work done in the THEMIS project. 

The results of the ESTER experiments will be used to support evaluations of source term and of accident management strategies. The information will serve as a basis for the improvement and validation of source term predictive models. A part of this work will be done in an analytical working group (AWG) composed of the project members where experience of the application and enhancement of simulation tools is shared. The ESTER project has strong links with other ongoing and concluded joint projects in this field: the BIP, STEM, THAI and THEMIS projects.

ESTER members' area  (password protected | reminder)


Finland, France, Germany, Japan, Korea, Sweden, the United States of America

Project period

September 2020 to August 2024


EUR 3.14 million