Noise Thermometry for Nuclear Applications

The effects of nuclear radiations on conventional thermocouples (type K, C and N) mainly used in irradiation experiments may create significant drifts of the signals. In order to solve these difficulties, the Commissariat à l´Energie Atomique has started to develop and qualify in laboratory conditions a miniature device, which combines a noise thermometer and thermocouples, for a future application in a research reactor. In this paper, a particular approach of a combined noise thermometer-thermocouples is described. Present measurements, based on a correlation and comparison method, are realized in laboratory at 300°C which represents the mean temperature in materials irradiation experiments. Referred measurement uncertainties are lower than ±1.5°C corresponding to the accuracy tolerance of conventional thermocouples at this temperature.