A method to avoid spatial treatment in xenon poisoning calculation while providing conservative reactivity estimates

A calculation method for xenon reactivity without spatial treatment while providing conservative estimates of that reactivity has been proposed. It is based on both upper and lower estimates of the reactivity. In order to obtain these estimates, the method requires a knowledge of minimum and maximum values of coefficients involved in equations of xenon reactivity which are functionals of space-time dependent xenon concentration and neutron flux shape. Accuracy of the method is sensitive to the range of variation of the mentioned functionals. For a simplified PWR model used in the present work the maximum change in the functionals is less than 10%. This provides reasonable accuracy for the method