The experimental work described in this paper is part of a collaborative programme agreed between CEA and the Dragon Project. The aim of the programme is the measurement of the relative conversion ratio in a reactor loaded with Teledial fuel elements. The results will allow us to check our calculational methods and assumptions upon which the calculations are based, in the case of a teledial core, which represents a very complicated geometry, specially, due to the presence of the U238 with its resonance. The programme of experiments described in the paper have been completed. Some preliminary results are presented in the second part of this report (Part 2).