will have little or no effect on the multiplexer. The glass capacitor performed very well up to 600 megarads. The JFETs were irradiated to a total integrated neutron dose of 4 X 1015 n/cm2 in a few hours and all showed permanent damage. The neutron flux exposure dose rate will be reduced to see if the temperature annealing at low neutron dose rates will eliminate the permanent damage. The Johnson noise thermometer conceptual design review was completed and the review team concluded that this design is a feasible long lifetime temperature sensor for SP-100. The tungsten/rhenium thermocouple design was also reviewed and approved for continued development as the long life temperature sensor for control of the SP-100 reactor. The pressure and flow sensor are in the early stages of design and development. The reflector control drive development assembly is nearly completed. The linear actuator and resolver assembly has been completed as well as the preliminary assembly of the rotary actuator. The linear actuators have been bench-tested and are now ready for high temperature tests. High temperature test of the rotary actuator and resolver will follow the linear actuator tests. The control drive motor bearing were sputter- coated with molybdenum disulfide and nickel as dry lubricants and are being tested in vacuum at 700 K. The molybdenum disulfide has low friction and has survived thermal/vacuum testing without degradation. The bearing coated with nickel failed. The reactor I&C development is progressing as planned. Shield Subsystem The GFS shield design configuration and materials selection (Fig. 20) are complete. The design satisfies the specified shielding requirements. Material compatibility testing showed that lithium hydride is not compatible with beryllium. So the shield is now designed with a barrier between the lithium hydride and beryllium. The lithium hydride powdered metallurgy fabrication process is under development, and will be validated by the fabrication, assembly and testing of the shield for the nuclear assembly test. The fabricated lithium hydride material is also being irradiated at temperature to determine its behavior in the predicted space power system environment. The seven year equivalent accelerated irradiation of lithium hydride will be completed in FY 1990. Heat Transport Subsystem The two critical components in the heat transport subsystem are the pump and the gas separator located as shown in Fig. 21. The pump is a thermoelectric electromagnetic pump that circulates the lithium in both the heat transport and the heat rejection subsystems. The temperature difference between the two lithium coolants is about 500 K and is used as the driving force for the thermoelectric cells to power the pump and circulate the lithium liquid metal in both subsystems. The pump magnetic configuration was simulated and tested to verify the analytical prediction of the magnetic performance. This test also allowed the designers to shape the magnets and minimize the magnet mass. The magnetic performance was predicted for two magnet structure types: one low carbon steel structure and one HIPERCO-27 structure, and two series of tests were conducted. The first series of three tests verified and calibrated the magnetic analyses code using the carbon steel magnetic structure. The second test series used HIPERCO-27 material (GFS design material) for the test article. The HIPERPO material was initially fabricated into predicted minimum mass
RkJQdWJsaXNoZXIy MTU5NjU0Mg==