The first Research Reactor reaches its criticality on 2nd December 1942. Nowadays, more than 300 research reactors are currently in operation. Over the past fifty years, research reactors have progressed through a variety of tasks. These have included materials research using neutron scattering and diffraction, materials characterization by activation analysis and radiography, isotope production, irradiation testing, as well as training, and service as centres of excellence in science and technology. With the sustained development in computer technology, the possibilities of code capabilities have been enlarged substantially. Consequently, advanced safety evaluations and design optimizations that were not possible a few years ago can now be performed. The purpose of the present thesis is to provide an overview of the accident analysis technology applied to the research reactor, with emphasis given to the capabilities of computational tools