Calibration fixture for induction furnace

A temperature calibration probe for use in an induction furnace in heat treating ends of nuclear fuel rod tubes, the fuel rod tubes having an elongated structure and the induction furnace being dimensioned to closely encompass the ends of the tubes, the probe comprising:

• a conductive structure dimensioned to correspond closely in response to electromagnetic induction heating to the elongated structure of the tubes at said ends;
• a plurality of temperature sensors disposed at spaced points along the probe, the temperature sensors being mounted in heat transfer relationship with the conductive structure of the probe and operable to produce a signal representing temperatures at the spaced points;
• and,
• means for coupling the temperature sensors to means for decoding the signal.

In combination, an induction furnace for heat treating ends of nuclear fuel rod tubes and a temperature probe, comprising:

• the induction furnace including means for generating an alternating electromagnetic field in a cavity, the cavity being dimensioned to closely receive at least one of the tubes, and means for adjusting the electromagnetic field in the cavity;
• the temperature probe including a conductive tube structure dimensioned to correspond closely to the nuclear fuel rod tubes at said ends and having a material responding to the electromagnetic field substantially similarly to a response of the tubes, whereby the conductive structure and the tubes responds substantially the same to inducement of current by the electromagnetic field;
• a plurality of temperature sensors disposed at spaced points along the probe, the temperature sensors being mounted in heat transfer relationship with the conductive structure of the probe and operable to produce a signal representing temperatures at the spaced points;
• and,
• means for coupling the temperature sensors to means for decoding the signal, whereby the electromagnetic field in the cavity can be adjusted to obtain predetermined operating conditions.