Exponential fitting of PWR decay heat data at short cooling time for use in the PRESTO experiment

• Exponential fitting of PWR decay heat data at short cooling time (1–40 min). PRESTO experiment. Levemberg-Marquard algorithm. Parametric study to the number exponentials used. Reduced model heat. Decay is thermal power released by a nuclear reactor after shutdown. In this work, we problem exponential for fuel sample between 1 and 40 min time. This has particular interest estimation, called experiment, where determined solving an inverse problem. To do this, generated synthetic through numerical simulation, fit them using different sums exponentials. The system considered UO2 (enriched 1% U5), irradiated 25 days in reflector Jules Horowitz Reactor. Neutronics calculations were performed with CEA’s codes TRIPOLI MENDEL, CEAV512 library. technique used sum Levenberg-Marquardt Our results show that three fits within precision 1%. means ensemble unstable isotopes releasing energy (cooling time) can be subdivided into main groups, are identified well-defined constant. Furthermore, sensitivity reduced model. that, when modifying exponentials, compromise accuracy (low residuals) stability (sensitivity errors data) exists. We conclude concerning represents best choice application methodology work extended other intervals rather than 1–40 min.