Fuel Materials


Since its very start in 1952, SCK•CEN has studied scientific and technical issues of the nuclear fuel cycle. During this history of nuclear fuel research, SCK•CEN investigated innovative concepts for future developments, assisted the nuclear industry in their challenges to improve reliability, efficiency and safety of nuclear fuel and performed fundamental studies in close cooperation with the academic world. 

Today, the nuclear fuel research resides under the group “Fuel Materials’ (FMA) of the Nuclear Materials Science institute (NMS). A team of researchers and project leaders performs studies on the nuclear fuel cycle, covering production, in-reactor performance and stability of the spent nuclear fuel.

The vast majority of these studies are performed in an international context and our main stakeholders are the fuel manufacturing industry, utilities, governmental and safety organizations and universities.

Main activities

In-reactor research of advanced nuclear fuels

In-reactor research of the performance of advanced nuclear fuels under Light Water Reactor (LWR) conditions (e.g. MOX fuel with elevated Pu content, MOX fuels with additives to increase the homogeneity, Thorium-Plutonium fuel, mixed ceramic-metallic (CERMET) fuels). They aim at investigating medium and long term options for advanced fuel cycles in LWR’s. The projects are conducted under bilateral contracts (projects CHIPS, CMP-I, THOMOX) or as part of various EU Framework Projects (OMICO, LWR-DEPUTY).

Spent LWR fuel research

Spent LWR fuel research is conducted in support of licensing long term intermediate storage (spent UO2 and MOX fuel) and in the context of the direct disposal of spent nuclear fuel. Examples are:

  • Stability of irradiated UO2 exposed to various atmospheres for long periods of time (up to 25 years)
  • Wetting and drying of leaking fuel rods 
  • Leaching studies of UO2 based and ThO2 based fuel

The projects are conducted under multilateral contracts  (projects DRYSTOR, WETFUEL),  as part of various EU Framework Projects (LWR-DEPUTY, FIRST NUCLIDES) or as fundamental studies in an academic context.

Fuel research for MYRRHA

Fuel research for MYRRHA focuses on licensing, demonstration of production and actualization of past research. SCK•CEN has a long history of applied fuel and cladding research for the European Fast Reactors (SNR300, EFR) with many R&D projects between 1960 and 1990 in BR-2, but also in the French, German and UK reactors (Rhapsodie, Phénix, KNK, DFR).

MYRRHA is PbBi cooled, but has a fuel design derived from SNR300 and EFR. The operating conditions of MYRRHA are in many aspects similar, but there remain several gaps to be bridged. Although one can rely on past R&D, the challenges remain big: implementation of past findings in modern codes (e.g. the fuel codes MACROS and TRANSURANUS), actualization of fabrication processes for fuel and cladding, filling knowledge gaps (clad-coolant compatibility, fast transient tests on fuel segments) and preparing complete licensing files. The research is performed in close cooperation of the MYRRHA teams of SCK•CEN and as part of various EU Framework Projects (MAXSIMA, MATTER, SEARCH, EUROTRANS).

Theoretical solid state research of nuclear fuel

This includes:

  • Improving the thermophysical modelling of in-reactor performance of nuclear fuel (development of the MACROS code)
  • Fundamental research to investigate the behavior of defects in actinide oxide systems at the atomic scale (Molecular Dynamics studies)

Research is performed in EU Framework Projects (OMICO, F-BRIDGE, FAIRFUELS, PELGRIMM) or in an academic context (master, PhD level) with ULB, Imperial College, …

Applied solid state research of actinide oxides

Applied solid state research of actinide oxides includes research on UO2 powders and pellets, ternary U-O-M phases (M = Cs, Na, K, Ba, …), pure and doped ThO2 and UO2 systems (Gd, Ce, Eu, …). The main goal is to improve our understanding of fundamental aspects of the actinide oxide system and at the same time to pass knowledge to the next generation of researchers and engineers. The research is performed as PhD theses in collaboration with the universities of Limoges, ULB, KUL and with many colleges and universities on master thesis level.

Partitioning research

Recently, the first steps are made in partitioning research with scoping studies on the stability of ionic liquids.



Head of expert group: Marc Verwerft