Fatigue monitoring and life cycle analysis of a recuperative heat exchanger in the primary circuit Original Research Article

The example of a recuperative heat exchanger is used to demonstrate the temperature monitoring and the thermal fatigue assessment of a component in the primary circuit of a PWR. After describing the geometry and the operating conditions, the placement of the thermocouples at locations of interest is shown. The temperature recordings show that the existing operational instrumentation was very slow and the fluid transient were actually much faster than anticipated. With a computer program allowing the reduction from outside wall to fluid temperature, the thermal inertia of the old instrumentation could be quantified. Consequently, old recordings from slow instrumentation could still be used. Thermal finite element computations are presented that yield quite favourable correlations between computations and measurements.