System 80+ Standard Plant Design Meeting Load Follow Requirements for the Future

Abstract

The capability of nuclear power plants to perform a wide range of load maneuvers is very important for electrical grids with large nuclear capacities. These maneuvers are required to assist in meeting peak load generation requirements and to maintain system stability during grid disturbances. The System 80+TM Standard Plant, an evolutionary advanced light water reactor designed and licensed by ABB Combustion Engineering, includes advanced design features to accommodate a wide range of load maneuvers. The plant design, rated at 1400 MWe, satisfies all of the EPRI Advanced Light Water Reactor(ALWR) Utility Requirements Document (URD) requirements on load follow, and is capable of accommodating various planned power maneuvers, frequency control operations, and load rejections. The System 80+ plant is designed for continuous operation in the reactor following turbine mode and includes these load follow capabilities:1. Daily and/or weekend power maneuvering at load change rates up to 5% of rated plant power per minute,2. step load changes, which provide spinning reserve capability,3. Automatic response to grid frequency changes satisfying peak-to-peak power changes of 10% of rated plant power at a rate of 5% of rated power per minute, and4. Load rejections from any power level without initiating a reactor trip and opening safety valves. The System 80+ Standard Plant includes proven design features that have evolved over many years to form an integrated design that can accommodate the aforementioned load follow capabilities. One of the key design feature is the use of 25 Part-Strength Control Element Assemblies (PSCEA), (i.e., gray rods) which provide greater flexibility in performing load maneuvering while minimizing perturbations to the core power distribution. Strategies have been developed for the System 80+ Standard Plant to accommodate the various load maneuvers. The strategies demonstrate that the integrated actions of the plant control systems and, if necessary, the plant operator, are more than sufficient to maintain proper control of the reactor core and ensure that plant operating limits are not exceeded during the performance of these load maneuvers. The strategies developed for System 80+ satisfy the following performance objectives: Maintaining sufficient core operating margin during load maneuvers, Satisfying fuel design requirements and operating limits during load maneuvers, Minimizing chemical reactivity control operations and the generation of waste water as a result of load maneuvers, and Avoiding delays in return to power following planned down power maneuvers.