Selection of sodium coolant for fast reactors in the US, France and Japan

Abstract

The joint paper presents a common view of fast reactor specific missions in the development of nuclear energy and a cross-analysis of merits and demerits of several Fast Reactors concepts studied worldwide and especially in the Generation-IV International Forum (GIF) framework.The paper provides the context for fast reactors development in the United States, France and Japan and focuses on the comparison on Sodium-cooled Fast Reactor (SFR), Gas-cooled Fast Reactor (GFR), and Lead-cooled Fast Reactor (LFR), i.e. the three fast reactor concepts that have the potential to meet the nuclear fuel cycle sustainability goals.The information provided in the article permits the reader to understand each country's objectives to see that not only the objectives searched for but also the technical orientations are converging. The authors underline that SFR technology evaluation relies significantly on the substantial base technology development programs within each country which is without comparison for the other two fast reactor technologies, e.g., SFR technology has already been developed to commercial or near commercial scale in each country whereas the performance of LFR and GFR technology is still uncertain.The main GFR merits are the potential for high temperatures and the easier possibilities for inspections and repairs. The main challenges are the fuel (fabrication, in-pile behavior), materials for high temperatures, and the implementation of mitigation means to manage severe core degradation. The main LFR merit is the lack of chemical reactivity of the lead coolant with air and water. The main challenges are the development of corrosion resistant structural and cladding materials, the implementation of mitigation means to manage severe core degradation, the density of the lead, and the comparably large core size.The selection of a reference fast reactor concept in view of possible industrialization is made on a national base, taking into account the each countries’ strategic objectives, existing technology base, the proven or expected technical performance, the R&D challenges and technical means to conduct that R&D, the possibility to share development costs and risks, etc. It is important to note that in different contexts, the U.S., French, and Japanese organizations have selected the SFR as their reference fast reactor concept.