tailieunhanh - Modelling of as-fabricated porosity in UO2 fuel by MFPR code

On this base, the mechanistic MFPR code, including physically-grounded models for the fuel porosity evolution in UO2 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. | Modelling of as-fabricated porosity in UO2 fuel by MFPR code EPJ Nuclear Sci. Technol. 2 19 2016 Nuclear Sciences . Tarasov and . Veshchunov published by EDP Sciences 2016 amp Technologies DOI epjn 2016013 Available online at http REGULAR ARTICLE Modelling of as-fabricated porosity in UO2 fuel by MFPR code Vladimir I. Tarasov and Mikhail S. Veshchunov Nuclear Safety Institute IBRAE Russian Academy of Sciences 52 B. Tulskaya 115191 Moscow Russia Received 3 October 2015 Accepted 16 February 2016 Published online 15 April 2016 Abstract. For consistent modelling of behaviour of as-fabricated porosity in UO2 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 UO2 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. 1 Introduction irradiated UO2 fuel in collaboration between IBRAE and IRSN Cadarache France 4 5 . The mechanistic approach The in-pile dimensional behaviour of oxide fuels in nuclear applied in this code allows the realistic consideration of fuel reactors is a well-known phenomenon of great technological porosity evolution self-consistently with analysis of FP interest. It is generally established that at the beginning of release based on physically-grounded parameters and irradiation the fuel densifies due to shrinking of the as- mechanisms. fabricated pores remaining from the fuel sintering process Some important modifications of the existing models of with a wide distribution of their sizes 1 2 . The densifica- MFPR and development of new .