Patent Number: 
Section: claims

1. An electrical distribution system for a nuclear power plant, comprising:at least one primary alternating current (AC) power source;a first plurality of AC loads of a plurality of nuclear reactor systems of the nuclear power plant, each of the first plurality of AC loads comprising a critical electrical load of the plurality of nuclear reactor systems that fails to a safety position based on a loss of electrical power from the primary AC power source;a first AC power bus that is electrically coupled to the at least one primary AC power source, the first plurality of AC loads, and a first critical battery system that comprises one or more non-qualified battery sources;a second plurality of AC loads of the plurality of nuclear reactor systems, each of the second plurality of AC loads comprising a non-critical electrical load of the plurality of nuclear reactor systems; anda second AC power bus that is electrically coupled to the at least one primary AC power source, the second plurality of AC loads, and a non-critical battery system that comprises one or more qualified battery sources. 2. The electrical distribution system of claim 1, wherein the first plurality of AC loads comprise engineered safety feature (ESF) electrical loads, and the one or more non-qualified battery sources of the first critical battery system comprise valve regulated lead acid (VRLA) batteries. 3. The electrical distribution system of claim 1, wherein the second plurality of AC loads comprise active post-accident monitoring (PAM) electrical loads and common electrical loads, and the one or more qualified battery sources comprise vented lead acid (V LA) batteries. 4. The electrical distribution system of claim 3, wherein the non-critical battery system comprises:a first battery train electrically coupled to a first channel of the second AC power bus; anda second battery train electrically coupled to a second channel of the second AC power bus, each of the first and second battery trains comprising one or more qualified battery sources that comprise VLA batteries. 5. The electrical distribution system of claim 4, further comprising a third battery train electrically coupled to both of the first and second channels of the second AC power bus, the third battery train comprising one or more qualified battery sources that comprise VLA batteries. 6. The electrical distribution system of claim 1, wherein the first critical battery system is sized to supply AC power to the first plurality of AC loads for about 24 hours based on a loss of electrical power from the primary AC power source. 7. The electrical distribution system of claim 1, wherein the non-critical battery systems is sized to supply AC power to the second plurality of AC loads for about 72 hours based on a loss of electrical power from the primary AC power source. 8. The electrical distribution system of claim 1, further comprising:a third AC power bus that is electrically coupled to the primary AC power source, the first plurality of AC loads, and a second critical battery system that comprises one or more non-qualified battery sources. 9. The electrical distribution system of claim 1, wherein each of the nuclear power systems comprises a passively cooled modular nuclear reactor. 10. A method for providing power to a nuclear power plant, comprising:providing at least one primary alternating current (AC) power source;providing a first plurality of AC loads of a plurality of nuclear reactor systems of the nuclear power plant, each of the first plurality of AC loads comprising a critical electrical load of the plurality of nuclear reactor systems that fails to a safety position based on a loss of electrical power from the primary AC power source;electrically coupling a first AC power bus to the primary AC power source, the first plurality of AC loads, and a first critical battery system that comprises one or more non-qualified battery sources;providing a second plurality of AC loads of the plurality of nuclear reactor systems, each of the second plurality of AC loads comprising a non-critical electrical load of the plurality of nuclear reactor systems; andelectrically coupling a second AC power bus to the second plurality of AC loads and a non-critical battery system that comprises one or more qualified battery sources. 11. The method of claim 10, wherein the first plurality of AC loads comprise engineered safety feature (ESF) electrical loads, and the one or more non-qualified battery sources of the first critical battery system comprise valve regulated lead acid (VRLA) batteries. 12. The method of claim 10, wherein the second plurality of AC loads comprise active post-accident monitoring (PAM) electrical loads and common electrical loads, and the one or more qualified battery sources comprise vented lead acid (VLA) batteries. 13. The method of claim 12, further comprising:electrically coupling a first battery train of the non-critical battery system to a first channel of the second AC power bus; andelectrically coupling a second battery train of the non-critical battery system to a second channel of the second AC power bus, each of the first and second battery trains comprising one or more qualified battery sources that comprise VLA batteries. 14. The method of claim 13, further comprising:electrically coupling a third battery train of the non-critical battery system to both of the first and second channels of the second AC power bus, the third battery train comprising one or more qualified battery sources that comprise VLA batteries. 15. The method of claim 10, further comprising:sizing the first critical battery system to supply AC power to the first plurality of AC loads for about 24 hours based on a loss of electrical power from the primary AC power source. 16. The method of claim 10, further comprising:sizing the non-critical battery systems to supply AC power to the second plurality of AC loads for about 72 hours based on a loss of electrical power from the primary AC power source. 17. The method of claim 10, further comprising:electrically coupling a third AC power bus to the primary AC power source, the first plurality of AC loads, and a second critical battery system that comprises one or more non-qualified battery sources. 18. The method of claim 10, further comprising:detecting a loss of primary AC power from the at least one primary AC power source;adjusting at least a portion of the first plurality of AC loads to their respective safety positions;supplying AC power to the portion of the first plurality of AC loads from the one or more non-qualified battery sources through the first AC power bus; andsupplying AC power to the second plurality of AC loads from the one or more qualified battery sources through the second AC power bus. 19. The method of claim 18, further comprising:detecting a restoration of primary AC power from the at least one primary AC power source;supplying AC power to the portion of the first plurality of AC loads from the at least one primary AC power source through the first AC power bus; andsupplying AC power to the second plurality of AC loads from the at least one primary AC power source through the second AC power bus.