Measurements in the CROCUS reactor at EPFL, Lausanne, are reported for the critical water level and the inverse reactor period for several different sets of delayed supercritical conditions. The experimental configurations were also calculated by four different calculation methods. For each of the supercritical configurations, the absolute reactivity value has been determined in two different ways, viz.: (i) through direct comparison of the multiplication factor obtained employing a given calculation method with the corresponding value for the critical case (calculated reactivity: calc); (ii) by application of the inhour equation using the kinetic parameters obtained for the critical configuration and the measured inverse reactor period (measured reactivity: meas). The calculated multiplication factors for the reference critical configuration, as well as calc for the supercritical cases, are found to be in good agreement. However, the values of meas produced by two of the applied calculation methods differ appreciably from the corresponding calc values, clearly indicating deficiencies in the kinetic parameters obtained from these methods. [All rights reserved Elsevier]