Title
State change modal method for numerical simulation of dynamic processes in a nuclear reactor.
Abstract
Modeling of dynamic processes in nuclear reactors is carried out, mainly, on the basis of the multigroup diffusion approximation for the neutron flux. The basic model includes a multidimensional set of coupled parabolic equations and ordinary differential equations. Dynamic processes are modelled by a successive change of the reactor states, which are characterized by given coefficients of the equations. In the modal method, the approximate solution is represented as an expansion on the first eigenfunctions of some spectral problem. The numerical-analytical method is based on the use of the dominant time-eigenvalues of a multigroup diffusion model taking into account delayed neutrons. In this work, the application of the modal methodology based on calculation of the dominant eigenvalues and eigenfunctions of α-eigenvalue problem has been tested for the VVER-1000 reactor test model. The last is characterized by the fact that some eigenvalues are complex. Reactor dynamics behavior is simulated for symmetrical and non-symmetrical control rods insertion/withdrawal. The power calculation results obtained with the modal method were compared with the numerical solution of the dynamics problem. A rather good agreement was shown for the problem with single delayed neutron precursor group.
Year
DOI
Venue
2017
10.1016/j.pnucene.2018.02.027
Progress in Nuclear Energy
Keywords
Field
DocType
Neutron diffusion equations,Multi-group approximation,Space-time kinetic,Spectral problem,Modal method
Delayed neutron,Parabolic partial differential equation,Neutron flux,Mathematical optimization,Computer simulation,Nuclear reactor,Ordinary differential equation,Control theory,Mechanics,Mathematics,Dynamic simulation,Heavy traffic approximation
Journal
Volume
ISSN
Citations 
106
0149-1970
0
PageRank 
References 
Authors
0.34
4
4