Keywords: metering reactivity, inhomogeneous inverse point kinetics, hardwired circuits, numerical integration, India PHWR, pressurised heavy water reactors, nuclear energy, nuclear power, nuclear reactors, coupled neutron kinetics
A new hardwire circuit for metering reactivity
Sub-criticality, criticality, and reactivity are the terms which are not annunciated in Indian PHWRs (Pressurised Heavy Water Reactors) and are thus not very clear to the reactor operators. These parameters are prime movers defining nuclear reactor and should be annunciated in control room by simple means to aid operator to view reactivity excursions while in power operation or during shutdown maintenance. A very novel circuit of a hardwire scheme to solve the coupled neutron kinetics is presented and its output is compared against analytical solutions. This scheme does not require any estimation technique and is robust as the instrument is based on basic reactor governing laws. This instrument is able to show the transients in reactivity as well as steady state values and is aimed for all Indian PHWRs for multi-decade operation. This technique is tunable for any research reactor or fast reactor too.