The hydrogen world consumption should increase significantly to progressively replace hydrocarbons. Due to its high power density, nuclear reactor should take an important place in this production. This paper focuses on the hydrogen production by thermochemical cycle using the heat available at 900°C of a new generation nuclear reactor. The chosen thermochemical cycle for this study is the iodine-sulphur thermochemical cycle water splitting.The process flowsheet under consideration has high total energy consumption. It has also many local energy needs unevenly distributed over a wide temperature range. The raw distribution of this energy gives a hydrogen production efficiency of 14.0%. To improve this, the proposed coupling is built using an energy distribution network with a coolant to meet the safety requirements. In this simple case, the efficiency of hydrogen production comes to 21.9%. By integrating a heat pump into the energy distribution network, the efficiency of production increases to 42.0%. The exergetic efficiency, increases from 59.3% to 85.8%.