1. Byong Guk Jeon, Ho Sik Kim
NQe 401 Exp. 1 Temperature measurement
NQe401
Byong Guk Jeon, Ho Sik Kim

2. Introduction Only measured by indirect method
=> Temperature can be measured indirectly using the change of physical properties such as pressure of gas, expansion of mercury, resistance of metal.

3. Thermocouple
TCs are a widely used type of temperature sensor and can also be used as a means to convert thermal energy into electrical energy. (known as the thermoelectric effect or Seebeck effect)

4. Thermocouple
Types by materials : K, E, J, N, and etc. Ex. K:Chromel (Ni-Cr alloy) / Alumel (Ni-Al alloy)
Types by structure

5. Resistance Temperature Detector (RTD)
RTD uses the relationship between electrical resistance and temperature:
Usually platinum wire, 1930년에 사용.

6. TC versus RTD

7. TC versus RTD TC RTD From 35$ From 130$ Price

8. Temperature instrumentation in NPP
Most critical process temperatures in nuclear power plants are measured using RTDs(16-32 per plant) and thermocouples.
Characteristics of RTDs in NPP
1. Nuclear grade(LOCA, seismic, radiation, etc)
2. 20 years life
3. <0.3°C accuracy
4. 4~8 second response time

9. Infrared Thermometer
Infrared thermometers measure the surface temperature of an
opaque object
Characteristics
Range:~760°C
Accuracy:±1°C
Response time:0.5s
58만원. IR sensor만 사면 33만원.