Reactivity Measurement Using the Area-Ratio Method in the BRAHMMA Subcritical System

The online reactivity monitoring of accelerator-driven systems is a crucial issue in reactor control and monitoring. The area-ratio method is one of the techniques for measuring the reactivity of subcritical systems using a pulsed neutron source. This technique has been used to measure reactivity at different locations in the subcritical assembly BRAHMMA developed at the Bhabha Atomic Research Centre, India. Since the reactivity measured by the area-ratio method is spatially dependent on the detector location, the Bell-Glasstone correction factor was used to correct the measured reactivity.