Fuel behaviour simulation with SCANAIR
F. Lamare, V. Bessiron, M. Petit. EUROSAFE 2004.
The SCANAIR code is developed by IRSN, in collaboration with “Electricité de France” (EDF) in the frame of the research program on fuel behaviour. Its objective is the description of the thermo-mechanical behaviour of highly irradiated PWR rods (UO2 and MOX) under Reactivity Initiated Accident (RIA).
The code takes into account the strong coupling between physical phenomena occurring during rapid transients: thermal dynamics (incl. clad-to-coolant heat transfer in sodium or water conditions), structural mechanics for the rod constitutive elements, and fission gas (FG) transient behaviour.
SCANAIR was qualified by systematic comparison to experimental results from the CABRI REP-Na program. This highlighted a very satisfactory overall behaviour of code, although it showed that the mechanical models for the pellets, in particular MOX, is to be further refined. Present directions in SCANAIR development are: to model post boiling crisis rod behaviour, to derive a criterion for clad failure prediction and to allow for estimating post failure events such as fuel ejection and thermal interaction with the coolant. It more and more relies on small scale modelling from which macroscopic behaviour is constructed by use of techniques such as homogenisation. .