# Approaching Nuclear Safety Culture in Fission and Fusion Technology
## 3 Nuclear Safety Culture in Fusion  
### ITER Project in the French Nuclear Context  
France is characterized by a large number of nuclear fission power plants and of nuclear facilities located in the whole country. France also hosts the largest fusion experiment for peaceful purposes in the world, named ITER. ITER is an acronym for International Thermonuclear Experimental Reactor and is built in the framework of a wide international collaboration in the Provence region in southern France, next to the French Alternative Energies and Atomic Energy Commission CEA Cadarache facility in Saint-Paul-les-Durance. Another much smaller fusion tokamak device, named Tore Supra, has been working since 1988 in the CEA Cadarache laboratories in the framework of a collaboration between CEA and Euratom (European Atomic Energy Community).  
ITER is the largest among more than one hundred fusion research facilities built worldwide since the 1950s, and is a major step to demonstrate the scientific and technological feasibility of fusion for possible future energy production. The project is funded and run by the following seven members that represent the 35 countries directly or indirectly participating in the project: Euratom (representing the European Union), the US, Russia, China, India, South Korea and Japan.  
ITER will not produce electricity but it will pave the way for its successor, the DEMO fusion reactor meant for electric energy production in an experimental environment. Future commercial reactors are envisaged only when full-scale electricity-producing fusion power stations are built after DEMO [9; 10].  
Nuclear safety is always a priority in activities with ionizing radiation, and France demonstrates outstanding records with important and wide experience in mastering nuclear science and technologies in all their numerous aspects, applying it also in the field of fusion energy.  
The practical implementations of nuclear safety concepts in fusion and fission reactors present some fundamental differences due to the physical and technological characteristics of each. However, the main concepts of NSC that are adopted in fusion reactors are also based on those of other types of installations with radioactive materials, especially from nuclear fission power plants.  
The fusion process is considered inherently safe and fission-type meltdown is not possible. The fusion reaction relies on a continuous input of a limited amount of fuel while any perturbation in the fusion reaction process will stop it immediately. The amounts of tritium fuel radioelement considered for some fusion facilities are of the order of only a few grams during plasma pulse, and its confinement measures are one of the most important safety objectives.  
Even in case of total loss of cooling, the confinement barriers conceived for fusion facilities would not be affected, keeping their safety function without reaching the melting temperatures of the materials.  
A system of multiple independent and redundant layers or barriers is designed also for fusion reactors to protect against any possible radioactive releases into the environment. This is the basis of the so-called Defense in Depth (DiD) concept that is adopted for both fission and fusion applications, with the same objective of protecting the health and safety of the public, workers and environment. The purpose of multiple barriers is to compensate for any possible potential mechanical or human failures so that no single layer, no matter how robust, is exclusively relied upon. In fusion reactors, the Vacuum Vessel (VV) represents the first confinement barrier while the buildings are the second level barrier. Where tritium is handled, there is also the need for an advanced detritiation system for the recovery of tritium from gas and liquids and to inhibit the outward diffusion of tritium; therefore, an efficient second dynamic confinement barrier with air pressure cascading in the buildings is conceived.