PLENUM SPRING AND GETTER ASSEMBLY

PURPOSE: To provide a plenum spring and a getter assembly for use in a nuclear fuel rod having a plenum spring design that holds a getter at a desired distance from a fuel column. CONSTITUTION: This plenum spring 27 is a wire including a first winding section 27b with a diameter greater than the diameter of a getter 23 installed therein, a second winding section 27c with a diameter smaller than the diameter of the getter 23, and a third winding section 27d with a diameter not necessarily but preferably equal to the diameter of the first winding section 27b. The winding sections 27b, 27c, 27d are connected in series along an axis, and the second winding section 27c formed at a neck is located between the first winding section 27b and the third winding section 27d. When a fuel rod is installed upright inside a nuclear reactor, the getter 23 compresses the first turn of the neck- forming winding wire section and is supported by the turn.