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 2.4: The SPHERE irradiation experiment: comparison of irradiation performance of pellets and spherepac MA-bearing driver fuel

Sander van Til1, A.V. Fedorov1, P.R. Hania1, E. D’Agata2, A. Cambriani3, J. Somers3
  • 1: NRG, Netherlands
  • 2: JRC-IET
  • 3: European Commission, Joint Research Centre, Institute for Transuranium Elements (ITU), Hermann-von-Helmholtz Platz 1, PO Box 2340, DE–76125 Karlsruhe, Germany


The SPHERE irradiation experiment is the latest in a series of irradiations studying the performance of minor actinide (MA) bearing driver fuels for future sodium fast cooled reactors (SFR). SPHERE has been designed to compare conventional pellet-type fuels with so-called sphere-pac fuels under similar conditions.The pellet and sphere-pac fuels have nearly identical compositions of U0.76Pu0.2Am0.03O2-x.

The SPHERE irradiation was conducted in the High Flux Reactor in Petten, within the FP7 project FAIRFUELS, and has run for 11 cycles between August 2013 and April 2015 up to an estimated burn-up of ~5% FIMA. Linear power in both fuel stacks was ~300 W/cm at the start of irradiation. A post-irradiation neutron radiogram has revealed central hole formation in the sphere-pac fuel only.

Post irradiation analyses are underway in FP7 project PELGRIMM and consist of non-destructive testing (NDT), i.e. profilometry, gammaspectrometry and puncturing of the pins for analysis of fission gas release. A summary of the irradiation history and preliminary results on the NDT campaign are presented.