Hot Helium Handler
Pebble-bed nuclear power plants, which would be cooled by helium gas and powered by uranium encased in graphite spheres, could provide safer nuclear power. One significant roadblock to the adoption of the pebble-bed reactor is the requirement of its superheated helium gas for a far more complex gas-turbine system than is needed by today’s nuclear plants, which produce much cooler steam. Potchefstroom University in South Africa has made the world’s first successful prototype of such a turbine system. Potchefstroom engineers built a 15-meter-long apparatus that, says lead engineer Gideon Greyvenstein, allows expansion of superheated gas directly from the reactor and compresses it for the return trip, tolerates temperatures of 700C, and includes novel control systems. The engineers developed modeling software to manage such critical operational concerns as overall system pressure. Building a full-blown pebble-bed plant requires decisions from South Africa’s government, as well as Eskom, the state utility, and its industrial partners. Those approvals could be granted within a year.