Cesium and iodine speciation in irradiated UO2 fuel

Journal Article (2025)
Author(s)

Jean Yves Colle (European Commission Joint Research Centre)

J. N. Zappey (European Commission Joint Research Centre)

O. Beneš (European Commission Joint Research Centre)

Marco Cologna (European Commission Joint Research Centre)

T. Wiss (European Commission Joint Research Centre)

R. J.M. Konings (TU Delft - RST/Reactor Physics and Nuclear Materials, European Commission Joint Research Centre)

Research Group
RST/Reactor Physics and Nuclear Materials
DOI related publication
https://doi.org/10.1016/j.jnucmat.2025.155715
More Info
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Publication Year
2025
Language
English
Research Group
RST/Reactor Physics and Nuclear Materials
Volume number
608
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Abstract

The presence of CsI in nuclear fuel has long been debated. Its formation significantly decreases volatility, thereby reducing the rate at which iodine and cesium are released from the reactor core during a nuclear accident. A series of samples were investigated by Knudsen Effusion Mass Spectrometry (KEMS) in order to determine whether CsI is present in irradiated nuclear fuel. The examined samples were pure CsI, CsI exposed to gamma radiation, CsI-doped UO2 simulated fuel and irradiated LWR fuel samples. The CsI and CsI-doped samples were examined to establish boundary conditions for the detection of CsI by KEMS. These samples indicated that the presence of CsI in fuel is characterized by three mass spectrometric signals Cs+, I+ and CsI+, with a peak ratio of CsI+ and I+ of 1:0.7. The examinations of irradiated fuels showed none of these characteristics and hence no evidence that CsI is present in irradiated LWR nuclear fuel, at least after a storage period of years.