Replacement of the Core Beryllium Reflector in the SAFARI-1 Research Reactor

The SAFARI-1 Research Reactor is a 20 MW high flux MTR and has been continuously operational for more than 46 years. In this period, the core beryllium reflector had never been replaced. An ageing management action to replace the reflector received priority due to the risks involved with failure or deformation of elements. This paper elaborates on the actions taken to replace the old and manage the new reflector. To this extent a reflector replacement procedure, backed up by core neutronic calculations and a test plan, was developed for the safe replacement of the reflector. A reflector management programme will ensure that records of reflector elements are kept and used to optimally manage usage of every element. Due to the historic nature of reflector utilisation in the SAFARI-1 core, deformation of the elements was unavoidable. These deformations will be monitored in the management programme for the new reflector. Deformation measurement of the old reflector is planned and could yield interesting comparisons with analytical results. The action plan for final disposal of the old reflector, although still in development, is also mentioned in this paper. (author)