Abstract: An automatic motion inhibit system for a nuclear power generating system for inhibiting automatic motion of the control elements to change the reactor power in response to turbine load changes. A final reactor power level setpoint is continuously compared with reactor power and a setpoint-greater-than-power signal is generated when the final reactor power level setpoint is greater than the reactor power. The final reactor power level setpoint is a setpoint within the capacity of a steam relief valve system which in no event is lower in value than the lower limit of automatic operation of the automatic motion control means. Also the reactor power demand or turbine load is continuously compared with a predetermined power demand threshold and a demand-less-than-threshold signal is generated when the reactor power demand is less than the demand threshold.

Abstract: An automatic motion inhibit system for a nuclear power generating system for inhibiting automatic motion of the control elements to reduce reactor power in response to a turbine load reduction. The system generates a final reactor power level setpoint signal which is continuously compared with a reactor power signal. The final reactor power level setpoint is a setpoint within the capacity of the bypass valves to bypass steam which in no event is lower in value than the lower limit of automatic control of the reactor. If the final reactor power level setpoint is greater than the reactor power, an inhibit signal is generated to inhibit automatic control of the reactor.

Abstract: A reactor trip on turbine trip inhibit control system for a nuclear power generating system which utilizes steam bypass valves. The control system inhibits a normally automatic reactor trip on turbine trip when the bypass valves have the capability of bypassing enough steam to prevent reactor trip limits from being reached and/or to prevent opening of the secondary safety pressure valves. The control system generates a bypass valve capability signal which is continuously compared with the reactor power. If the capability is greater than the reactor power, then an inhibit signal is generated which prevents a turbine trip signal from tripping the nuclear reactor.

Abstract: A reactor trip on turbine trip inhibit control system for a nuclear power generating system which utilizes steam bypass valves. The control system inhibits a normally automatic reactor trip on turbine trip when the bypass valves have the capability of bypassing enough steam to prevent reactor trip limits from being reached and/or to prevent opening of the secondary safety pressure valves. The control system generates a bypass valve capability signal which is continuously compared with the reactor power. If the capability is greater than the reactor power, then an inhibit signal is generated which prevents a turbine trip signal from tripping the nuclear reactor.

Abstract: A turbine follow system and method for pressurized water reactors with a multiplicity of load bypass valves to provide a substitute load upon a load rejection by shunting excess steam around the load to a condenser. The system provides a circuit whereby not more than one valve is opened on any one system or operator error by utilizing circuit redundancy and a permissive gate operated by one of the redundant circuits.

Abstract: A turbine follow system and method for Pressurized Water Reactors utilizing load bypass and/or atmospheric dump valves to provide a substitute load upon load rejection by bypassing excess steam to a condenser and/or to the atmosphere. The system generates a variable pressure setpoint as a function of load and applies an error signal to modulate the load bypass valves. The same signal which operates the bypass valves actuates a control rod automatic withdrawal prevent to insure against reactor overpower.