Instantaneous flux measurements using the background signal of the rhodium self-powered neutron detector

Abstract

The background current produced by a rhodium self-powered neutron detector (RSPND) with an integral background lead has been investigated to determine its relationship to the neutron flux seen by the detector. The background current and steady state flux were measured at the core midplane for all fuel assemblies, and good linearity was seen. Under transient conditions, the background current, when delayed fission product decay contributions are included, follows the flux reasonably well although with a slight lag. This opens the possibility of using the RSPND during transient conditions.