Integral form of the control rod calibration curve in the new core configuration of HWZPR using rod insertion method

The reactivity worth and calibration curve of control rods are important physical parameters on account of nuclear safety of the reactor core. Reactivity characteristics of control rods must be determined in the first criticality and also after any substantial changes in a reactor core. The required time to measure the reactivity worth by various methods depends mostly on the quality of the reactivity compensation. The rod-insertion method has some specific advantages which make such compensation unnecessary, while yielding both integral and differential reactivity worth curves, as well as total reactivity worth. In this study, one control rod of Heavy Water Zero Power Reactor (HWZPR) pitch is calibrated experimentally using rod-insertion method to verify calculation results for the new core configuration. Total reactivity worth of the control rod is obtained 0.001759 ± 2.8%Δk/k and 0.001801 ± 5%Δk/k by experiment and calculation, respectively. The relative difference between the experimental and calculated values of control rod reactivity worth is about 2.36%, which indicates a good agreement between the applied experimental method and calculation. The results show that the reactivity worth of the control rod depends on the flux value and position of detectors in rod insertion method. •The rod insertion method is used for control rod calibration.•The reactivity worth of the control rod depends on the flux value in rod insertion method.•The reactivity worth of the control rod depends on the position of detectors in this method.