| abstract |
A mechanical drive system (10) for moving alternate nuclear reactor fuel rods (14) within the nuclear reactor core (12) and relative to the remaining stationary nuclear reactor fuel rods (16) so as to axially displace the movable fuel rods (14), and enriched and natural uranium fuel zones defined therein, relative to similarly defined enriched and natural uranium fuel zones within the stationary fuel rods (16) in order to optimize utilization of excess or free neutrons produced within the nuclear reactor core within a fuel cycle. The nuclear reactor fuel rods (14, 16) all have a length which is less than that of standard-sized nuclear reactor fuel rods, and therefore, a plenum chamber (20) is able to be defined between an upper core plate (22) and an auxiliary upper core plate (24). A drive plate grid assembly (36, 38) is attached to the movable fuel rods (14), and hydraulic drive mechanisms (46) move the grid assembly (36, 38) and the movable fuel rods (14) so as to axially displace the fuel rods (14) relative to the stationary fuel rods (16) whereby the enriched and natural uranium fuel zones defined within the fuel rods (14, 16) optimally operationally interface throughout the fuel cycle. The movable fuel rods (14) are progressively moved during the fuel cycle such that at the beginning of the fuel cycle, the enriched and natural uranium fuel zones defined between adjacent fuel rods (14, 16) are mis-aligned, while at the end of the fuel cycle, the fuel zones are aligned in horizontal layers. |