NuFuel & MMSNF 2015

First Workshop on Research into Nuclear Fuel in Europe
and Materials Modeling and Simulation for Nuclear Fuels Workshop
Karlsruhe, Germany, November 16th to 18th, 2015

Updated: Tue 08 Dec 2015, 14:27

Talk 1.1: Preparation and characterization of nanostructured UO2 for LWR fuel safety assessment

Vaclav. Tyrpekl, M. Cologna, J. Somers
  • European Commission, Joint Research Centre, Institute for Transuranium Elements (ITU), Hermann-von-Helmholtz Platz 1, PO Box 2340, DE–76125 Karlsruhe, Germany

Abstract

During its lifetime in a nuclear power plant the fuel (UO2) undergoes significant restructuring at the periphery of the pellet, with the grains (10µm or more) of the fresh fuel converting to a ‘cauliflower’ like structure with grain size of 100–300 nm (20% porosity). Despite the investigations made thus far on this structure, their scope is severely limited due to the high radioactivity of the irradiated fuel. To circumvent this limitation we have developed a process to produce UO2 pellets with nano-crystalline structure to enable a series of separate effect investigations on surrogate material (mechanical properties, gas retention, etc.) and a deeper understanding of this material and its safety assessment. This paper concentrates on the preparation of the nanostructured UO2 material, starting from ex oxalate and sol gel powders, consolidation using spark plasma sintering (SPS), characterisation and mechanical property determination.