APPARATUS FOR LIMITING THE EFFECT OF AXIAL HYDRAULIC PRESSURE EXERTED ON FUEL ASSEMBLIES OF WATERCOOLED NUCLEAR REACTORS

摘要

The fuel rods are located between an upper plate and a lower plate; and an end piece is fixed to both the top and bottom ends of the fuel rods. On each end piece is a shock-absorber pot contg. an elastic sleeve made e.g. of a spring steel tube with a longitudinal slot. A centreing pin is located in the sleeve to provide the fuel rods with a limited amt. of axial movement. The frictional force of the sleeve on the pin prevents an axial movement of a fuel rod during normal changes in hydraulic pressure, but the pot has a radial hole via which the pressurised water can escape if the fuel rod expands axially along the pin. If the fuel rods expand axially, water can escape out of the shock absorber pot.