Faced with the huge energy challenge of our century due to a rising World population, and the need to reduce carbon dioxide emissions to limit the impact on climate change, nuclear energy has a key role to play in the energy mix. Six designs of Generation IV nuclear reactors are currently being developed following an international agreement between thirteen member countries (the Generation IV International Forum) -Argentina, Brazil, Canada, France, Japan, the Republic of Korea, South Africa, Switzerland, the United Kingdom, the United States, Euratom, People’s Republic of China, and the Russian Federation- for cooperation in the research and development of future generation of nuclear energy systems. These reactors should be ready for deployment by 2030 to replace the current portfolio of nuclear reactors (mainly second generation Light Water Reactors LWRs) at the end of their operating licenses. These new technologies are not only highly innovative, but also have the potential to provide safer, more reliable and sustainable designs. One main challenge for their development and commercialisation in the near future is a thorough understanding and modelling of the nuclear fuel physico-chemical properties since the fuel is at the heart of the energy production process.