Patent Number: 
Section: claims

1. A nuclear power plant having a nuclear reactor, comprising: a first steam supply system connected between the nuclear reactor and a steam turbine,  a second steam supply system branched from the first steam supply system and connected downstream of the steam turbine,  a first valve in the first steam supply system for adjusting steam pressure to the steam turbine,  a second valve in the second steam supply system for adjusting branched steam pressure,  a first controller that generates a first control signal for the first valve and a second control signal for the second valve, and  a second controller that generates a third control signal for the second valve, the third control signal having priority over the second control signal;  and two controlling valves operating independently from one another, wherein said second valve is configured to be operated by at least one of said two controlling valves. 2. A nuclear power plant, according to  claim 1 , wherein each of said two controlling valves are controlled by a different control signal. claim 1 3. A nuclear power plant, according to  claim 1 , wherein said two controlling valves comprise a servo valve and a fast acting solenoid valve. claim 1 4. A nuclear power plant, according to  claim 3 , wherein said servo valve is controlled by said second control signal and wherein said fast acting solenoid valve is controlled by said third control signal. claim 3 5. A nuclear power plant, according to  claim 3 , wherein said fast acting solenoid valve controls operation of said second valve when said servo valve is malfunctioning. claim 3 6. The nuclear power plant according to  claim 1 , wherein the third control signal is generated if the second valve is closed and the pressure in the steam turbine decreases. claim 1 7. The nuclear power plant according to  claim 1 , wherein the third control signal includes an opening signal for the second valve. claim 1 8. The nuclear power plant according to  claim 7 , wherein the third signal is generated if the second valve is closed within a predetermined time period after receiving the second signal. claim 7 9. The nuclear power plant according to  claim 7 , wherein the third signal is released if the second valve is opened within a predetermined time period after receiving the third signal. claim 7 10. The nuclear power plant according to  claim 1 , wherein the second valve is multiplexed, and each second valve accepts the second signal and the third signal. claim 1 11. The nuclear power plant according to  claim 7 , wherein the third signal is released if the steam pressure from the nuclear reactor is a predetermined value. claim 7 12. The nuclear power plant according to  claim 6 , wherein the third signal is generated only once. claim 6 13. The nuclear power plant according to  claim 1 , wherein the third control signal is generated at least when the plant is not in regular operating mode. claim 1 14. The nuclear power plant according to  claim 1 , wherein the third control signal acts to avoid that both the first valve and the second valve are closed. claim 1