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

Poster 1.1: Outcomes from investigations of oxide spherepacked fuels synthesis

Joseph Somers1, C. Cozzo2, Fabienne Delage3, Daniel Freis1, S├ębastien Picart3, Manuel Pouchon2
  • 1: European Commission, Joint Research Centre, Institute for Transuranium Elements (ITU), Hermann-von-Helmholtz Platz 1, PO Box 2340, DE–76125 Karlsruhe, Germany
  • 2: PSI - Switzerland
  • 3: CEA, DEN - France

Abstract

The European FP–7 project PELGRIMM addresses the development of Minor-Actinide (MA) bearing oxide fuels consolidated as pellets and spherepac for Sodium-cooled Fast Reactors. Two fuel compositions: MABB and MADF, are under investigation. In the Minor Actinide Bearing Blanket (MABB), MA-oxide is concentrated in UO2 and sub-assemblies are located in the radial blanket of the core. In MADF – Minor Actinide Driver Fuel – MA oxide is diluted in the (U,Pu)O2 driver fuel.

Even if powder metallurgy, implemented to supply (U,Pu)O2 standard fuels at industrial scale, can be used at lab-scale to prepare Am-bearing fuel samples, dust-free routes and simplified methods, are essential to scale-up the Am-bearing fuel fabrication processes. Three options have been investigated within the project: two are based on the sol-gel processes that lead to dense or porous spherical particles and the other relies on the adaptation to oxide fuels of the Weak Acid Resin technology.

For the MARINE irradiation test (implemented within PELGRIMM) that aims at comparing a sphere-packed and pelletized (U,Am)O2-x fuel: the preparation of pellets includes a stage of UO2 porous beads infiltration by a low acid Am nitrate solution, followed by heat treatments, pressing and sintering. The preparation of sphere-pac particles (50 and 800µm) was performed using direct co-precipitation of mixed (U,Am) nitrate solution by external gelation before heat treatments and vibro-packing.

In parallel, a variant of the internal gelation route, for the gelation of the drops using a microwave cavity instead of a silicon oil hot bath, has been investigated. Finally, the Weak Acid Resin flowchart has been revisited and adapted to oxide fuels for the actual synthesis of (U,Am)O2 beads and pellets.

The experiences gained on fuel synthesis during these campaigns are presented and conclusions for future approaches are drawn.

Acknowledgments:

The authors appreciate the support of the scientists and institutions involved in the FP–7 PELGRIMM Project, as well as the financial support of the European Commission through the grant agreement 295664.