A method to identify an accidental control rod drop with inverse distance weighted interpolation

•An alternative method to identify the accidental drop of a control rod in PWR reactor.•A control rod drop identification method based on the readings of the thermocouples.•The identification of the dropped control rod is made using an inverse distance weighted interpolation. The goal of this work is to develop a method to identify the accidental drop of a control rod in the core of a pressurized water reactor based on the readings obtained from thermocouples. The method is based on the physical premise that, due to the local effect that the event produces on the distribution of power and temperature, the greatest variations take place at the fuel assembly position where the control rod is inserted, as well as in its neighbouring regions. In order to identify the control rod, the method presented here analyses the profiles on temperature in the thermocouples and calculates virtual temperature at the positions of the fuel assemblies of the control rods via inverse distance interpolation. The results have shown the feasibility of the method, which has the advantage of not relying of previously simulated data to train the neural networks as seen in previous works.