Verification of iterative matrix solutions for multipoint kinetics equations

J. Tommasi (1, 2) , G. Palmiotti (3)

1 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)
2 SPRC - Service de Physique des Réacteurs et du Cycle
3 INL - Idaho National Laboratory

Multipoint kinetic equation systems have been solved numerically using matrix algebra software and 1st to 4th order implicit schemes based on single-step matrix propagators. These matrix schemes have been validated successfully on demanding point kinetics benchmarks with various prescribed reactivity insertions. Verification tests have also been performed on a simple 3-region fast reactor core model with asymmetric step or ramp reactivity insertions and cross-checked with the multipoint kinetics SACRE code developed at INL and based on existing and validated stiff ODE solver packages. Accurate results can be obtained at a limited time expense. The reason for intriguing results obtained in some transients has been elucidated and linked to the multipoint matrix coefficient interpolation method during the transient.

Keywords: multipoint kinetics equations; implicit matrix methods

Domains: Physics [physics]; Nuclear Experiment [nucl-ex]; Physics [physics]; Nuclear Theory [nucl-th]

J. Tommasi, G. Palmiotti. Verification of iterative matrix solutions for multipoint kinetics equations. Annals of Nuclear Energy, 2018, 124, pp.357-371. ⟨cea-02339617⟩