Speciation and release kinetics of the fission products Mo, Cs, Ba and I from nuclear fuels in severe accident conditions - Archive ouverte HAL Access content directly
Conference Papers Year : 2018

## Speciation and release kinetics of the fission products Mo, Cs, Ba and I from nuclear fuels in severe accident conditions

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Yves Pontillon

#### Abstract

A speciation and release kinetics study of the gaseous fission products freed from nuclear fuels in conditions of severe accident (temperature range 1300°C – 2500°C) as a function of the applied thermodynamic conditions is carried out using the experimental feedback collected at CEA within the VERCORS and VERDON programs. The nature of the major species involved are deduced from the analysis of the specific features of the Cs-Mo-Ba-I-O chemical system in the composition range of irradiated nuclear fuels. Stable gaseous Cs and Ba molybdate species, i.e. $Cs_2Mo_2O_7$ (g) and $BaMoO_4 (g)$, clearly predominates in oxidising conditions, which contributes to increase significantly the released fraction of molybdenum as compared to reducing conditions. An analytical model accounting for thermo-chemistry in the release rate of chemically reactive elements is applied to estimate the release of Cs, I, Mo and Ba in severe accident conditions. Good agreement is achieved with on-line measurements

### Dates and versions

cea-02400191 , version 1 (09-12-2019)

### Identifiers

• HAL Id : cea-02400191 , version 1

### Cite

Ch. Riglet-Martial, J. Sercombe, Yves Pontillon. Speciation and release kinetics of the fission products Mo, Cs, Ba and I from nuclear fuels in severe accident conditions. WRFPM 2018, Sep 2018, Prague, Czech Republic. ⟨cea-02400191⟩

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