Extension of the reactor dynamics code DYN3D to SFR applications - Part I: Thermal expansion models

Two IAEA benchmarks on the Phenix end-of-life experiments were used for a more detailed validation of the extended version of DYN3D. While Part II presents the validation study performed against the static neutronic benchmark of the control rod withdrawal tests, the results of the initial stage of the natural circulation test are covered in Part III of the paper.