Fission products and nuclear fuel behavior under severe accident conditions Part 2: Fuel behavior in the VERDON-1 sample

E. Geiger (1) , Le Gall Claire (1) , A. Gallais-During (1) , Yves Pontillon (1) , J. Lamontagne (1) , Eric Hanus (1)

1 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)

Within the framework of the International Source Term Programme (ISTP), the VERDON programme aims at quantifying the source term of radioactive materials in case of a hypothetical severe accident in a light water reactor (LWR). Tests were performed in a new experimental laboratory (VERDON) built in the LECA-STAR facility (CEA Cadarache). The VERDON-1 test was devoted to the study of a high burn-up UO$_2$ fuel and FP releases at very high temperature ($\approx$2600°C) in a reducing atmosphere. Post-test qualitative and quantitative characterisations of the VERDON-1 sample led to the proposal of a scenario explaining the phenomena occurring during the experimental sequence. Hence, the fuel and the cladding may have interacted which led to the melting of UO$_2$-ZrO$_2$ alloy. Although no relocation was observed during the test, it may have been imminent.

Mots clés: UO2 irradiated fuel; Fuel behaviour; LWR; Severe accident; VERDON tests; Post-test characterisations; Fuel-cladding interactions

Domaines: Physique Nucléaire Théorique [nucl-th]; Physique Nucléaire Expérimentale [nucl-ex]

E. Geiger, Le Gall Claire, A. Gallais-During, Yves Pontillon, J. Lamontagne, et al.. Fission products and nuclear fuel behavior under severe accident conditions Part 2: Fuel behavior in the VERDON-1 sample. Journal of Nuclear Materials, 2017, 495, pp.49-57. ⟨10.1016/j.jnucmat.2017.08.002⟩. ⟨cea-02388727⟩