Forced convective subcooled boiling is of interest for many industrial applications, especially as a possible heat transfer regime in the core of pressurized water reactors (PWR). Due to practical interest, R12 was used as a testing fluid to simulate water between 10 and 18 MPa. This article presents a study of the forced convective subcooled boiling of R12 based on previous models and new physical considerations. The axial void fraction profile is determined and compared to R12 experimental data obtained on the DEBORA loop at CEA/Grenoble. The research yielded a void fraction model, shown to be valid for R12 as well as water, and based on a new correlation for the distribution parameter and on a continuous actual quality versus equilibrium quality function extended to the partially developed boiling region. Results showed good agreement with the DEBORA R 12 experimental data as well as the experimental data obtained by Bartolomei et al. [Thermal Engng. 29(3) 132] in water at high pressure. (C) 2004 Elsevier Ltd. All rights reserved.