A two-moment semi-spectral warm microphysical scheme has been implemented inside the meteorological model MERCURE of the EDF company. In particular, in this scheme, a new formulation of the buoyancy flux is proposed, which is coherent with the corrigendum of Mellor (1977) but differs from Bougeault (1981). As for the validation the model, the non- precipitating cloud microphysics is validated by comparing the numerical simulations of fifteen cases of cooling tower plumes with data from a measurement campaign in Bugey nuclear power plant in 1980. Satisfactory results are obtained on the plumes...