Fuel assembly design concept and mixed cycle length operation method for long cycle length pressurized water reactor operation

A method for operating a pressurized water reactor operation, comprising:

• preparing a fuel assembly including a fresh fuel rods that operate for a preset first operation time and once-used fuel rods that operate for a second operation time longer than the first operation time;
• creating an operation schedule of the pressurized water reactor based upon the first operation time of the fresh fuel rods and the second operation time of the once-used fuel rods;
• and operating the pressurized water reactor by repeating the operation schedule,
• wherein the operating the pressurized water reactor by repeating the operation schedule includes:
• operating the pressurized water reactor for a first cycle of a predetermined period of time by using a fuel assembly including a first set of the fresh fuel rods in a first region and a first set of the once-used fuel rods in a second region;
• after the first cycle operation is completed, discharging the first set of the once-used fuel rods to the outside of the pressurized water reactor;
• loading, after the first cycle operation is completed, a first portion of the first set of the fresh fuel rods into the second region in the fuel assembly;
• discharging a second portion of the first set of fresh fuel rods to the outside of the pressurized water reactor;
• loading a second set of the fresh fuel rods into the first region and operating the pressurized water reactor for a second cycle of a preset period of time;
• loading, after the second cycle operation is completed, a second set of fresh fuel rods into the second region;
• and a third set of the fresh fuel rods into the first region and operating the pressurized water reactor for a third cycle of a preset period of time.