A peer-reviewed journal published by K. N. Toosi University of Technology

Document Type : Research Article

Authors

Department of Nuclear Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran

Abstract

In the present work, a time-dependent neutron diffusion simulator is developed utilizing the second order of average current nodal expansion method. Generally, nodal methods can accurately simulate the reactor core with coarse meshes as long as the sizes of a fuel assembly. In this case, an adopted iterative approach is used for resolving the time-dependent three-dimensional multi-group neutron balance equations coupled with six-group precursor equations. In order to evaluate the implemented methodology, two popular transient problems are used including TWIGL two-dimensional seed-blanket reactor and three-dimensional LMW LWR. For indicating the precision of the method, the numerical results of high (second) order approach also have been compared with the basic methodology i.e. the zeroth order solution. From the comparison of obtained results with references, the suitable and precise simulating of transient schemes can be comprehended using the time-dependent second order average current nodal expansion method. Moreover, the results confirm that the second order solution can treat the coarse mesh dynamic problems with more accuracy relative to the basic approach.

Highlights

• Investigation of second order of average current nodal expansion method.
• Comparing zeroth and second order solution results.
• Perform static and dynamic calculation for each test case and compare the results with reference.

Keywords

Abed, A. and Poursalehi, N. (2018). Neutron noise simulation in the nuclear reactor core based on the average current nodal expansion method. Annals of Nuclear Energy, 114:482–494.
Abed, A., Poursalehi, N., and Zolfaghari, A. (2017). Point flux nodal expansion scheme applied to the neutron noise analysis of the nuclear reactor core. Progress in Nuclear Energy, 94:133–146.
Christensen, B. (1985). Three-dimensional static and dynamic reactor calculations by the nodal expansion method.
Espinosa-Paredes, G. (2017). Fractional-space neutron point kinetics (F-SNPK) equations for nuclear reactor dynamics. Annals of Nuclear Energy, 107:136–143.
Gehin, J. C. (1992). A quasi-static polynomial nodal method for nuclear reactor analysis. Technical report, Oak Ridge Inst. for Science and Education, TN (United States); Massachusetts
Ginestar, D., Verd´u, G., Vidal, V., et al. (1998). High order backward discretization of the neutron diffusion equation. Annals of Nuclear Energy, 25(1-3):47–64.
Hageman, L. and Yasinsky, J. (1969). Comparison of alternating-direction time-differencing methods with other implicit methods for the solution of the neutron group diffusion equations. Nuclear Science and Engineering, 38(1):8–32.
Mohammadnia, M., Pazirandeh, A., and Sedighi, M. (2013). Development of a computer code for neutronic calculations of a hexagonal lattice of nuclear reactor using the flux expansion nodal method. Nuclear Technology and Radiation Protection, 28(3):237–246.
Poursalehi, N. and Abed, A. (2021). Second order of average current nodal expansion method for the neutron noise simulation. Nuclear Engineering and Technology, 53(5):1391–1402.
Poursalehi, N., Zolfaghari, A., and Minuchehr, A. (2013). Development of a high order and multi-dimensional nodal code, ACNEC3D, for reactor core analysis. Annals of Nuclear Energy, 55:211–224.
Poursalehi, N., Zolfaghari, A., and Minuchehr, A. (2014). Three-dimensional high order nodal code, ACNECH, for the neutronic modeling of hexagonal-z geometry. Annals of Nuclear Energy, 68:172–182.
Putney, J. (1986). A hexagonal geometry nodal expansion method for fast reactor calculations. Progress in Nuclear Energy, 18(1-2):113–121.
Smith, K. S. (1979). An analytic nodal method for solving the two-group, multidimensional, static and transient neutron diffusion equations. PhD thesis, Massachusetts Institute of Technology.
Valavi, K., Pazirandeh, A., and Jahanfarnia, G. (2020). Three-dimensional time-dependent neutron diffusion simulation using average current nodal expansion method. Nuclear Technology and Radiation Protection, 35(3):189–200.