Simulation of the Treat-Upgrade Automatic Reactor Control System

This paper describes the design of the Automatic Reactor Control System (ARCS) for the Transient Reactor Test Facility (TREAT) Upgrade. A simulation was used to facilitate the ARCS design and to completely test and verify its operation before installation at the TREAT facility. The ARCS is a microprocessor network based closed loop control system that provides a position demand control signal to the transient rod hydraulic drive system. There are four identical servo-hydraulic rod drives and each operates as a position control system. The ARCS updates its position demand control signal every 1 msec and its function Is to control the transient rods so that the reactor follows a prescribed power-time profile (planned transient). The Main Control Algorithm (MCA) for the ARCS is an optimal reactivity demand algorithm. At each time step, the MCA generates a set of reference reactor functions, e.g., power, period, energy, and delayed neutron power. These functions are compared to plant measurements and estimated values at each time step and are operated on by appropriate algorithms to generate the reactivity demand function. The data necessary to calculate the reference functions is supplied from a Transient Prescription Control Data Set (TPCDS). The TPCDS specifies the planned transient as a fixed number of simply connected independent power profile segments. The developed simulation code, models the TREAT reactor kinetics, the hydraulic rod drive system, the plant measurement system, and the ARCS control processor MCA.