Fuel spacer and fuel assembly

摘要

With an arrangement that the axial distance from the upper end of a first opening area to the upper end of the second opening area is equal to the axial distance from the upper end of a first coupling member to the upper end of a second coupling member, when a spring member is moved upwardly relative to round cells, the upper end of the second coupling member comes into contact with the upper end of the second opening area, and the spring members receives upwardly acting forces from fuel elements. The spring member is thereby prevented from inclining with respect to flow of a coolant. Simultaneously, the upper end of the first coupling member contacts the upper end of the first opening area, and the spring member is stably held in a condition where it is aligned with the direction of the coolant flow. Also, since the axial distance from the lower end of the first opening area to the lower end of the second opening area is smaller than the axial distance from the lower end of the first coupling member to the lower end of the second coupling member, the lower end of the first coupling member does not come into contact with the lower end of the first opening area when the fuel element is inserted. Thus, the friction force produced during passage of the fuel member along the spring member is small and the fuel element can be inserted more easily.