Measurement of 14C in spent fuel: use of ozone

14C is a radionuclide that forms in nuclear fuel during its irradiation. In the spent fuel reprocessing process, or more precisely during the nitric dissolution step, it is divided between the different flows, with a part in gases emitted during dissolution and the rest in nitric spent fuel dissolution solution containing solid residues and hulls. The subject of this paper is the measurement of 14C in spent fuel dissolution solution, a first in the nuclear field. The study helped to establish the distribution of this radionuclide during the dissolution of a UOx3 spent fuel.