Image Number 5 for United States Patent #4038133.
A reactor has a core formed by a plurality of laterally adjacent fuel assemblies, each assembly comprising a vertically elongated casing containing a bundle of fuel rods and having an upper end connected to a tubular suspension rod forming the primary suspension means for the casing, failure of this means permitting the fuel assembly to drop from the core. In each instance, an instrumentation tube having an upper end supported independently of the primary suspension rod, extends downwardly through the latter, and centrally through the casing to the lower end of the latter. This instrumentation tube and the fuel assemblies adjacent to each other remain suspended so as to form vertically fixed parts relative to any one assembly that might drop accidentally. Each of the casings have latch means for normally latching the casing to one of these fixed parts so as to each casing it cannot fall substantially relative to that one of the parts in the event of a failure of its tubular suspension rod normally forming its primary suspension.