Speaker
Description
An old idea is being revisited: using magnetohydrodynamic (MHD) energy conversion as a topping cycle for industrial-scale nuclear fusion and fission power plants. If successful, this approach could increase the efficiency of a conventional nuclear power plant from about 35% using a steam cycle alone (a frog), to over 55% with a combined MHD–steam conversion system (a prince) – an obviously worthwhile goal. There are four reasons for revisiting this issue, one societal, three technical. First, concerns about CO2 emissions and climate change are far more serious today than during the original MHD era, which effectively ended in the 1990’s. Improving efficiency helps by making nuclear power substantially more economically competitive. Second, there have been technological advances, primarily the development of high field (B > 15T) HTS magnets, compared to the B < 5T fields available during the MHD era. Higher B should improve MHD performance and reduce capital cost. Third, a first-principles analytic theory has been developed that predicts the critical condition on the seed number density required to stabilize the previously show-stopping ionization instability, which led to serious performance deterioration in early experiments. Fourth, a procedure has been developed to design an efficiency optimized MHD channel cross-sectional shape as a function of length, using modern 3-D additive manufacturing techniques. Detailed results for the design of an optimized disk-Hall MHD generator will be presented.
This work is supported by the BT Charitable Foundation and US DoE grant DE-FG02-91ER54109.