Subcritical Reactivity Measurements in ZED-2

Abstract

The Zero Energy Deuterium (ZED-2) reactor was operated to provide validation data for subcritical reactor states. Moderator drain experiments were conducted to collect power transient data for analysis by inverse-point kinetics, determining the negative reactivity of the partially drained reactor core. Separate experiments employed a fission chamber to determine a count rate corresponding to these subcritical states. This chamber was calibrated to determine neutron flux at the chamber location. Analysis of these measurements is currently underway and preliminary results are presented here.