| 摘要 |
PROBLEM TO BE SOLVED: To provide a fuel assembly that suppresses increase in change rate of reactivity during state change between high temperature and low temperature, and increases the negative void reactivity coefficient. SOLUTION: This fuel assembly 1 comprises a plurality of uranium fuel rods 3, a plurality of burnable poison containing fuel rods 4 containing gadolinia, and a water rod WR. In two corner sections on a diagonal line orthogonal to the other diagonal line passing the corner facing a control rod CR, one burnable poison containing fuel rod 4 is arranged at the corner of the outer most layer adjacent to the inner surface of a channel box 7. Another burnable poison containing fuel rod 4 adjacent to the former burnable poison containing fuel rod 4 is arranged in the outer most layer. Such an arrangement of the burnable poison containing fuel rods 4 functions so as to decrease the total amount of effective gadolinia with a shielding effect of gadolinia. Therefore, the negative void reactivity coefficient can be increased, and the increase in change rate of reactivity during the state change between high temperature and low temperature can be suppressed. COPYRIGHT: (C)2009,JPO&INPIT
|
