ATWS boron analysis for a BWR using the FNPK equation

The aim of this work is investigate the Boron effects in a BWR during Anticipated Transient Without Scram (ATWS) event. The ATWS are considered events which might produce a severe accident in a Boling Water Reactor (BWR). To mitigate this accident, a borated water solution is injected to absorb neutrons to control the power. This action is an alternative way to shutdown the reactor quickly and effectively. The boron in the reactor core produces atypical neutron absorption in combination with the intrinsic feedback mechanisms, producing effects of anomalous diffusion in neutron behavior. To describe this effect in this work we apply the Fractional Neutron Point Kinetics (FNPK) equation. The FNPK equations is ad hoc to modeling the dynamic behavior, due to considering in explicit form the macroscopic cross section due to absorption, and anomalous diffusion effects, which are not possible with the classical representation of neutron point kinetics equation. The results of the numerical experiments showed that the fractional-order derivative of the FNPK is crucial in the dynamic behavior of the injection of Boron in the nuclear reactor.