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5.6.4.2 Nuclear

One difficulty to be overcome in the field described above consists in verifying the resistance of materials in realistic conditions. Future fission reactors core will have very specific parameters, and aging of materials under irradiation and temperature is difficult to simulate. Corresponding experiments can indeed take several years. For instance, homogeneity of nano-oxide repartition in the metals must remain stable under irradiation; otherwise the mechanical and thermal resistance properties could dramatically deteriorate.

This crucial question also induces difficulties for the international research project for fusion. These specific materials will not be tested in the frame of Iter, because the neutron flow inside Iter reactor will be much less intense than in the future production reactor. Only Demo, the reactor planed after Iter, that should prefigure the industrial implementation, will present conditions close to the real industrial ones. But it will not be built before several decades. New materials that are studied currently will then have to wait at least the opening of the Japanese material research center of the international project.

Composite ceramic materials are now a great subject of interest worldwide. Many ways are under study, but most of them do not meet the requirements in terms of temperature, aging due to irradiation. Moreover, specific properties like shaping or tightness to gas produced during the fission reaction (for cladding) are worrying issues.