Validation of new procedure of axial xenon oscillation dampening in pressurized water reactors (PWRs) - Case study

Xenon oscillation is a serious issue in nuclear power plants that affects the efficiency of such power plants. Xenon oscillations result from the imbalance between three key parameters, flux distribution in the core, Xenon distribution, and lastly iodine distribution. An improved procedure to simulate and dampen Xenon oscillations by determining only two parameters is previously proposed by the authors (Shimazu, 2009; Al Nuaimi et al., 2019). These two parameters can be calculated from actual nuclear reactor data obtained from nuclear power plants during their operation. The previously mentioned improved procedure assists the nuclear operators in determining when to insert and withdraw the control rods and the number of control rods' steps involved in order to eliminate Xenon oscillations. In this paper, the approach described earlier (Al Nuaimi et al., 2019) will be validated by solving for the two reactor parameters, namely, σaϕ and the proportional constant for Xenon concentration difference on axial offset , through determination of the stability index, γ and angular velocity, ω. This can be done by using fitting algorithm on PWRs' real data in order to characterize the expected Xenon oscillations behavior. The Axial Offset is plotted utilizing plant data obtained from a Generic PWR simulator. Using linear fitting, the values of γ and ω are then obtained to determine σaϕ and which can be inserted in a two-point model to plot the resultant Axial Offset. Both Axial Offset plots from the Generic PWR Simulator and the two-point model are quantitatively compared and evaluated in this present study.