Modelling of as-fabricated porosity in UO₂fuel by MFPR code

Abstract

Abstract. For consistent modelling of behaviour of as-fabricated porosity in UO 2 fuel irradiated under various conditions of in-pile and out-of-pile tests as well as under normal and abnormal conditions of nuclear reactor operation, the additional analysis of experimental observations and critical assessment of available models are presented. On this base, the mechanistic MFPR code, including physically-grounded models for the fuel porosity evolution in UO 2 fuel under various irradiation and thermal regimes, is refined. These modifications complete the consistent description of the fuel porosity evolution in the MFPR code and result in a notable improvement of the code predictions.

A mathematical model to describe the alpha dose rate from a UO2 surface

“…This can expose the microstructure of the pellet surface in the event of a containment breach, post-operation [7,9]. These grains are typically 10-100 µm in size [10]. After a pellet-clad breach, water can migrate in; inter-granular radiation-induced oxidative dissolution occurs, eventually dislodging grains from the pellet, surrounding them in water [4,11].…”