AP1000 fuel design and core operations

The fuel design and core operation of the AP1000 reactor use proven technologies while enhancing thermal and operation margins. The AP1000 fuel design is similar to the design that is used in 17*17 plants worldwide, with enhancements to increase fuel reliability and thermal margins. The core control strategy of the AP1000 reactor is designed to allow power maneuvers without changing boron concentrations, which simplifies reactor operations. This control strategy is accomplished through the use of the MSHIM (mechanical shim) reactivity control system, which uses a combination of gray rods and black rods for reactivity control. In addition, black shutdown rods are used to provide significantly enhanced shutdown margins as compared to a typical Westinghouse reactor. The core monitoring function is accomplished in the AP1000 reactor through the use of the BEACON system, utilizing signals from fixed in-core detectors. This system provides enhanced operational support as well as increased operation margins, because measured parameters can be used to eliminate the need for bounding analyses