SPACER GRID FOR PRESSURIZED WATER REACTOR FUEL ASSEMBLY

摘要

A support grid of a nuclear fuel assembly for a pressurized water reactor is provided to enhance thermal tolerance in a circulation process of cooling water by enabling outermost cells of a support grid spring to be in planar-contact with a fuel rod. A support grid(10) of a nuclear fuel assembly includes an introducing cell, inner grid plates, and external grid plates(40,41). An introducing tube penetrates the introducing cell. The inner grid plates are cross-implemented in a grid shape to form plural fuel rod cells where a fuel rod penetrates. Plural fluid mixing wings are protruded upward at the crossing portions of the inner grid plates. The external grid plates(40,41) are implemented to enclose an outermost portion of the inner grid plates. The external grid plates(40,41) include a vertical support portion and a contact spring. A vertical slot penetrates a center of the vertical support portion and the vertical support portion is attached to upper and lower surfaces of the vertical slot. The contact spring is connected to a mid-position of the vertical support portion and includes a longitudinal section which is curved to the outside.