High-temperature tungsten-cell fixed points for on site calibration of pyrometers for the measurement of melting temperature of nuclear fuels

The melting plateaus of W-γW
₂
C eutectic point in graphite and tungsten crucibles were investigated by means of radiation thermometry for the first time. W-cell fixed point showed good repeatability of the melting temperature: it can provide the means of realizing high-temperature fixed points for on site calibration of radiation thermometer in an induction furnace for the measurement of melting temperatures of nuclear fuels. The temperature value of W-γW
₂
C eutectic point will be determined precisely by use of graphite cell. An effect of temperature uniformity of an induction furnace on the melting plateau shape is also determined by use of Al
₂
O
₃
fixed point.