Use of SP-100 thermometry technology to improve operation of electric power plants

Control of the nuclear power source for the SP-100 electric power supply required a thermometer that would be 1% accurate at temperatures to 1100°C (1300 K) with no drift and unattended operation for more than 7 years in moderate radiation environment. No conventional thermocouples or resistance thermometers could meet these goals. However, Johnson noise thermometers were found to be able to meet such goals and were adapted for use in the SP-100. These temperature sensors do not drift; their calibrations can be validated at any time by noise measurements independently of their DC characteristics. This Johnson noise technology also has direct application to two problems in conventional electric power plants: in situ calibration of conventional resistance thermometers installed in steam systems at temperatures up to about 560°C; and measurement of combustion chamber temperatures up to about 1100°C. This paper describes how such a signal processor was used in several tests to calibrate commercial resistance temperature devices installed in TVA´s Kingston steam power plant, USA