A Thermochemical Hydrogen Production System Based on a High-Temperature Fusion Reactor Blanket

A conceptual fusion synfuel production system has been developed with the unique features of: (1) a fusion blanket producing high-temperature (1250/sup 0/C) process heat, and (2) the GA sulfur-iodine thermochemical cycle. The system incorporates a two-zone blanket which achieves a tritium breeding ratio of 1.1 while delivering a high fraction (30%) of the fusion heat at high temperatures (1250/sup 0/C). The multiple barriers to tritium permeation in the blanket design permit the hydrogen product to meet 10CFR20 regulatory requirements without stringent requirements on the tritium recovery systems. A ceramic heat exchanger, incorporating SiC tubes and headers to contain the process stream and a cooled, Inconel 718 pressure shell to contain the helium, was designed for transferring the heat from the high-temperature coolant to the process. A good heat-line match of the blanket heatsource temperature distribution to the requirements of the thermochemical plant was attained under the dual goal of maximizing process efficiency and minimizing the hydrogen cost. The results are a process efficiency of 45%, an overall plant efficiency of 43%, and an estimated cost of hydrogen of $12 to $14 per Gigajoule of hydrogen ($11 to $13 per million Btu).