NUCLEAR REACTOR CORE LOADING AND OPERATION STRATEGIES

摘要

PROBLEM TO BE SOLVED: To provide fuel cores which accommodate longer operating cycles with higher power densities while reducing or eliminating concerns associated with placing fresh or higher reactivity fuel directly adjacent to control elements.SOLUTION: Cores include different types of control cells in different numbers and positions. A periphery of each core just inside the perimeter may have higher reactivity fuel in outer control cells, and lower reactivity cells may be placed in an inner core inside an inner ring. The cores can include about half fresh fuel positioned in higher proportions in the inner ring and away from inner control cells. The cores can be operated with control elements in only the inner ring control cells for reactivity adjustment. The control elements in the outer control cells need to be moved only at sequence exchanges. Near end of a cycle, reactivity in the cores may be controlled with inner the control cells alone, and the control elements in the outer control cells can be fully withdrawn.