Latest achievements of CEA and AREVA NP on HTR fuel fabrication
Résumé
Extensive research and development programs on the (Very) High Temperature gas cooled Reactor (V/HTR) are being conducted by many countries mainly promoted by the attractiveness of this concept and its capability for other applications than electricity production, such as high temperature process heat and cogeneration. In this international context, the Commissariat à l'Energie Atomique (CEA) and AREVA NP through its project called ANTARES (Areva New Technology for Advanced Reactor Energy Supply) conduct a V/HTR fuel development and qualification program, among which one major activity is dedicated to the mastering of the nuclear fuel fabrication technology. The fuel concept selected for this project is the compact design based on UO2 kernels and SiC coating. First laboratory-scale experiments were performed to recover the know-how of HTR-coated particles and fuel element manufacturing. The different stages of UO2 kernel fabrication by the Gel Supported Precipitation (GSP) process were reviewed and improved. Experimental conditions for the Chemical Vapour Deposition (CVD) of coatings have been defined on dummy kernels supported by a modelling approach of the CVD process. The compacting processes formerly used at CERCA were reviewed and updated. In order to support a future industrial manufacturing factory and to meet the next short-term challenge, which is the fabrication of coated particle batches that will be compacted for the first irradiation test scheduled in OSIRIS, a lab-scale experimental manufacturing facility, named CAPRI (CEA and AREVA PRoduction Integrated) line has been set up and is in operation since early 2005. The CAPRI line is composed of a manufacturing line for TRISO particles, named GAIA, located at CEA Cadarache, and a compacting line for fuel elements based at CERCA, AREVA NP Subsidiary, Romans. Since early 2005, many tests have been performed leading to a better understanding and optimization of coating particle and compact manufacturing processes. In support to this fuel fabrication tool, development of accurate characterization methods were carried out to supply products meeting the specifications and to provide feed-back information to enhance fuel production quality.