A semi-analytical treatment of xenon oscillations

摘要: Abstract A novel approach is developed to investigate xenon oscillations within a two-group two-region coupled core reactor model incorporating thermal feedback and poison effects. Group-wise neutronic coupling coefficients between the regions are calculated applying associated fundamental first mode eigenvalue separation values. The resultant nonlinear state space representation of behavior quite suitable for evaluation reactivity induced power transients such as load following operation. however comprises multi-physics sub-systems with extremely distant relaxation times whose stiffness treatment inquire costly multistep implicit numerical methods. An adiabatic sluggish dynamics therefore proposed way out. helps further system linear time varying (LTV) framework whereby semi-analytical established. This scheme incorporates matrix exponential analytical solution perturbed efficient tool study operation control purposes. Poison updated larger intervals which exclude need specific schemes stiff systems. Simulation results axial offset conducted on VVER-1000 at beginning (BOC) end cycle (EOC) display acceptable compared available benchmarks. LTV investigated stability analysis systems these two stages employing concept Lyapunov exponent.