Neutron Sensors in the SP-100 Reactor Control System

The reference reactor control approach for the mature Generic Night System (GFS) utilizes highly reliable and diverse reactor outlet temperature measurements for control and protection. Although system dynamic analyses demonstrated that this approach is satisfactory for various modes of operation (including transients involving failure or degradation of equipment), the use of a Neutron Monitoring System (NMS) for initial startup and for an early period of power operation has been studied to improve the performance of the reactor control design. Control strategies were developed, simulation analyses were produced, and stability margins were examined. In this updated control approach, the signals from the NMS are used for the initial startup, for restarts, for power range control, and for protection from overpower transients as long as reliable data is avaliable from the NMS. The results show satisfactory performance for the, updated controls. If the lifetime of the NMS is shorter than that of the flight system, the reactor control will revert to the reference control approach employing reactor outlet temperature measurements only.