A novel nuclear-based integrated system for electrical power and compressed hydrogen production is proposed. The hydrogen is produced through the four-step Cu-CI cycle for water decomposition. A Rankine cycle is used to generate the power, part of which is used for the electrolysis step in the hybrid thermochemical water decomposition cycle and the hydrogen compression system. In the proposed design of the four-step thermochemical and electrical water decomposition cycle, only the hydrolysis and the oxygen production reactors receive thermal energy from the nuclear reactor. The nuclear thermal energy is delivered to the integrated system in the farm of a supercritical fluid. The nuclear reactor, which is based on the supercritical water-cooled reactor, is responsible for delivering the thermal energy to the system, which is simulated using Aspen Plus and assessed with energy and exergy analyses. It is determined that the energy and the exergy efficiencies of the proposed system are 31.6% and 56.2% respectively, and that the integrated system is able to produce 2.02 kg/s of highly compressed hydrogen and 553 MW of electrical power. (C) 2016 Elsevier Ltd. All rights reserved.