We study the interaction of hydrogen with zirconium. This system is technologically important because, among other applications, zirconium is used as structural material in nuclear reactors due to the combination of its mechanical properties and to the low cross-section that it presents for the absorption of neutrons. Using a calculus program based on the jellium model for the material, we obtain values of important properties in the determination of the macroscopic behaviour of the Zr-H system, such as the variation of the electronic density and of the induced density of states due to the presence of the hydrogen in the matrix of Zr. With these basic quantities we obtain other important ones that derive from these, such as the volume, and the heat of solution of hydrogen in zirconium. The general features of this method are discussed and the corresponding results are compared with experimental data, as well as with other theoretical models. (C) 2002 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved.