Reliability and vulnerability studies of the SP-100 dual-loop thermoelectric-electromagnetic pump

This research has developed a transient model of the dual-loop thermoelectric-electromagnetic pump of the SP-100 space nuclear power system and performed a parametric analysis assessing the reliability and vulnerability of the pump to overheating of the secondary coolant. Results show that the pump ceases to operate when the secondary coolant temperature either equals that of the primary coolant or exceeds 1255 K, regardless of the value of the primary coolant temperature. In any case, increasing the secondary coolant temperature degrades the SP-100 pump performance through both reducing the electric current produced by the thermoelectric generators and the magnetic flux of the pump. Because the SP-100 pump employs a self-induced magnet at secondary coolant temperatures lower than 1255 K but higher than the primary coolant temperature, the pump maintains forward operation because both the electric current and the magnetic field reverse direction. However, had the SP-100 pump been designed with a permanent magnet, raising the secondary coolant temperature beyond that of the primary coolant temperature would only reverse the electric current, causing the pump to operate in reverse. Results also show that although insulating the pump's magnetic structure from the secondary coolant ducts insignificantly affects the steady-state nominal operation of the pump, it improves pump performance and reduces the pump's vulnerability to external heating of the secondary coolant to temperatures in excess of 1000 K.