Research on controlled thermonuclear fusion as a new source of energy is carried out in devices called tokamaks, where matter is brought to high temperature (plasma state) and confined by magnetic fields. Interactions between the plasma and the walls of the vacuum chamber of tokamaks releases impurities, which can affect plasma performance. Different conditioning methods are used to control the surface state of the vacuum chamber, and thus impurity fluxes. These mainly use low-temperature plasmas (glow or radio-frequency discharges) in hydrogen or helium, but also deposition of thin layers of boron, because of its ability to trap by chemical affinity impurities like oxygen. With the advent of metallic plasma facing components and the extension of plasma duration in superconducting tokamaks, like ITER and WEST, operated in the Institute of Research on Magnetic Fusion (CEA Cadarache, France), innovative wall conditioning techniques to maintain optimal surface state and performances are under development. The aim of this thesis is to characterize and evaluate in WEST the relevance for ITER of different methods of boron injection, both a priori and in real time. The work will consist on the one hand to participate in experiments on WEST and to analyze experimental data (location and lifetime of boron deposits, effect on plasma performance). In order to understand the transport of boron, the candidate will work with plasma boundary numerical models (SOLEDGE, EIRENE, DIS). This work, combining experiments and simulations, will consolidate the understanding of the physics of wall conditioning in a metallic environment and predicting consequences for ITER and future fusion devices.