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On the numerical solution of the point reactor kinetics equations
Suescun-Diaz, D.,Espinosa-Paredes, G. Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.6
The aim of this paper is to explore the 8th-order Adams-Bashforth-Moulton (ABM8) method in the solution of the point reactor kinetics equations. The numerical experiment considers feedback reactivity by Doppler effects, and insertions of reactivity. The Doppler effects is approximated with an adiabatic nuclear reactor that is a typical approximation. The numerical results were compared and discussed with several solution methods. The CATS method was used as a benchmark method. According with the numerical experiments results, the ABM8 method can be considered as one of the main solution method for changes reactivity relatively large.
Vyawahare, Vishwesh A.,Datkhile, G.,Kadam, P.,Espinosa-Paredes, G. Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.2
The aim of this work is the analysis, design and hardware implementation of the fractional-order point kinetics (FNPK) model along with its closed-loop controller. The stability and closed-loop control of FNPK models are critical issues. The closed-loop stability of the controller-plant structure is established. Further, the designed PI/PD controllers are implemented in real-time on a DSP processor. The simulation and real-time hardware studies confirm that the designed PI/PD controllers result in a damped stable closed-loop response.
Fractional Radioactive Decay Law and Bateman equations
C.-A. Cruz-Lopez,G. Espinosa-Paredes 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.1
The aim of this work is to develop the fractional Bateman equations, which can model memory effects insuccessive isotopes transformations. Such memory effects have been previously reported in the alpha decay,which exhibits a non-Markovian behavior. Since there are radioactive decay series with consecutive alphadecays, it is convenient to include the mentioned memory effects, developing the fractional Bateman Equations,which can reproduce the standard ones when the fractional order is equal to one. The proposed fractionalmodel preserves the mathematical shape and the symmetry of the standard equations, being the onlydifference the presence of the Mittag-Leffler function, instead of the exponential one. This last is a veryimportant result, because allows the implementation of the proposed fractional model in burnup and activationcodes in a straightforwardway.Numerical experiments showthat the proposed equations predict highdecay rates for small timevalues, in comparisonwith the standard equations,which have high decay rates forlarge times. This work represents a novelty approach to the theory of successive transformations, and opensthe possibility to study properties of the Bateman equation from a fractional approach
Energy optimization of a Sulfur-Iodine thermochemical nuclear hydrogen production cycle
Juarez-Martinez, L.C.,Espinosa-Paredes, G.,Vazquez-Rodriguez, A.,Romero-Paredes, H. Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.6
The use of nuclear reactors is a large studied possible solution for thermochemical water splitting cycles. Nevertheless, there are several problems that have to be solved. One of them is to increase the efficiency of the cycles. Hence, in this paper, a thermal energy optimization of a Sulfur-Iodine nuclear hydrogen production cycle was performed by means a heuristic method with the aim of minimizing the energy targets of the heat exchanger network at different minimum temperature differences. With this method, four different heat exchanger networks are proposed. A reduction of the energy requirements for cooling ranges between 58.9-59.8% and 52.6-53.3% heating, compared to the reference design with no heat exchanger network. With this reduction, the thermal efficiency of the cycle increased in about 10% in average compared to the reference efficiency. This improves the use of thermal energy of the cycle.