COMPARISON OF SEVERE ACCIDENT BEHAVIOR OF ACCELERATOR DRIVEN SUBCRITICAL AND CONVENTIONAL CRITICAL REACTORS

摘要

In recent years the interest for reactors coupled with proton accelerators has been revived /1, 2, 3/. The idea to use accelerators goes back to the forties and fifties, when the main interest was in the generation of fissionable material. The new application areas are more related to the burning (transmutation) of plutonium / minor actinides / long lived fission products and power production. These newly proposed devices may first be used for nuclear waste burning and may later become an alternative to current systems/options as the LWR (light water reactor) and the LMR (liquid metal reactor). A European proposal for an accelerator driven system is being promoted by Rubbia /2/. This is a fast lead-cooled subcritical core coupled to a proton accelerator. The protons impinging onto flowing lead near the center of the core generate about 30 neutrons per spallation process. These neutrons are multiplied in the subcritical core according to 1/(1-k). Though the design of an ADS system is not yet fixed, some first estimates on the potential safety behavior have already been made. Generally it is claimed that the ADS is a system with extraordinary safety potential, a judgment which is mostly related to the subcriticality of the system. In the following some investigations concerning this judgment are offered.