Improvements in or relating to nuclear reactors

reference is made to steam generating heavy water reactors and to means for simplifying the removal and replacement of fuel channel assemblies in the calandria. The fuel channel assemblies described have cooling water inlet pipes secured to the lower ends of the fuel containing tubes which vary in length in accordance with their distance from the centre line of the calandria, the shorter pipes being located adjacent to the centre line and the longer pipes being located towards the periphery of the calandria, thus providing a space beneath the calandria to facilitate access to the pipes. (UK)