Granted Patent B1

US 7,742,555 · App. 12/172,688 · Granted Jun 22, 2010

Abstract

Claims (12)

1. A method of controlling a nuclear reactor during a load rejection transient, the nuclear reactor including a Reactor Coolant System having a hot leg with a temperature, T hot , and a cold leg with a temperature, T cold , a turbine having an impulse chamber and a steam dump system having steam dump valves, comprising the steps of:

generating a first temperature error signal based on an amount by which a reactor coolant average temperature exceeds a reference temperature, said reactor coolant average temperature determined from an average of T hot and T cold , and said reference temperature determined from a pressure measured in the impulse chamber of the turbine;

generating a second temperature error signal based on a power error signal provided when power level of the turbine is reduced and power level of the reactor exceeds the power level of the turbine;

summing said temperature error signals to generate a valve control signal for the steam dump valves;

actuating the steam dump system in response to said valve control signal.

2. The method of claim 1 wherein said turbine power is based on steam pressure measured inside the impulse chamber of the turbine.

3. The method of claim 1 wherein said load rejection is about fifty percent (50%).

4. The method of claim 1 wherein said valve control signal controls a valve positioner.

5. The method of claim 4 wherein said valve positioner enables opening of steam dump valves in said steam dump system.

6. The method of claim 5 wherein said steam dump valves are selected from the group consisting of condenser dump valves and atmospheric steam dump valves.

7. The method of claim 5 wherein said steam dump valves comprise at least four banks of valves.

8. The method of claim 1 further comprising converting said power mismatch error signal into a temperature error signal.

Assignments (9)