Preliminary Design and Analysis of a Very-High-Temperature Reactor-Driven Hydrogen-Electricity Cogeneration System

Abstract The very-high-temperature reactor (VHTR) is an innovative fourth-generation nuclear energy technology suitable for pairing with iodine-sulfur (IS) cycle for nuclear hydrogen production. This study designs a new VHTR-driven hydrogen-electricity cogeneration system integrating IS cycle and helium closed Brayton cycle, and studies the impact of key parameters on system performance. As the total compression ratio increases, the net output work of the system increases, and the energy utilization efficiency rises. As the split ratio increases, the heat sink loss of the auxiliary cooler (AC) increases, and the energy utilization efficiency decreases. As the reactor inlet temperature increases, the variation range of the split ratio is larger, causing a larger variation range of the hydrogen production rate. When the AC becomes a process heat supply unit, the hydrogen-electricity cogeneration system becomes a hydrogen-electricity-heat polygeneration system, whose energy utilization efficiency increases with the split ratio. At the reactor inlet temperature of 550 °C and the total compression ratio of 3.0, the variation range of the split ratio is 0.007–0.769. When the split ratio increases from 0.007 to 0.769, the energy utilization efficiency of the hydrogen-electricity cogeneration system decreases from 46.4 % to 23.2 %, while that of the hydrogen-electricity-heat polygeneration system increases from 47.5 % to 55.6 %.