| 摘要 |
A Nuclear fuel assembly for a nucler boiling water reactor comprising a fuel channel of substantially square cross-section, a plurality of vertical fuel rods arranged in sub-bundles with substantially square cross-section, a vertical channel-formed support member with a canter (7a) for the passage of water, said center being connected to wing parts (8) said sub-bundles of fuel rods being surrounded by said fuel channel and spaced apart by the channel-formed support member (7,8) fixedly connected to the fuel channel (1), the cruciform center (7a) of said support member being limited by the central parts of channel-formed support member, which conforms to the corner portions of said sub-bundles, in the region between the corner portions of the sub-bundles directed towards the center. According to the invention in each sub-bundle (6) of fuel rods (10) at least one fuel rod position has been removed from the corner portion of the sub-bundle (6) positioned nearest to the center (7a) of the fuel assembly, and an enlarged cruciform center (7a) is formed by the channel-formed support member (7,8), shaped in accordance to the reduced corner portions of the sub-bundles. The enlarged cruciform center (7a) of the channel-formed support member makes it possible to contain a larger quantity of non-boiling water in the central part of the fuel assembly, which results in better neutron moderation in the central part of the fuel assembly. |
