A reactivity meter with uncertainties

Abstract

Three sets of effective kinetics parameters were measured and evaluated for the fuel rod core of the IPEN/MB-01 research reactor. A correlation matrix among all these effective kinetics parameters is taking into account to reduce the inferred reactivity uncertainties. This work considers the propagation of the uncertainties inherent in these sets of effective delayed neutron parameters to the inferred reactivities. The comparisons to the reactivity and its uncertainty values produced by the Inhour Equation came into a very good agreement and reinforces the validity of the whole procedure for the development of this reactivity meter with uncertainties. The reduction of the reactivity uncertainty values compared to previous works is significant. The analyses of some specific cases of the evaluation IPEN(MB01)-LWR-RESR-015 reveal that its reactivity values are in accordance with those of this work. However, its reactivity uncertainty values for positive reactivities seems to cancel the uncorrelated component of the uncertainties.