Study on the basic of spallation target for accelerator driven system

Abstract

A study on the basic of spallation target for Accelerator Driven System (ADS) has been done. ADS is a subcritical assembly combined with a high-power proton accelerator. In the center of the subcritical assembly, there is a spallation target for producing primary neutrons that will be multiplied by the subcritical core surrounding it. The neutrons are produced via spallation reaction which occurs when the spallation target is bombarded by high-energy protons. The spallation target has to be designed so that the number of neutrons escaping from the target per incident proton is maximum and the power density deposited on it is high (~1 MW/litter). The spallation target can be made of a solid or liquid material such as Pb, Hg, U, W, Ta, or Pb-Bi which are the most preferred materials for spallation targets. But, today Pb-Bi is the reference material for ADS applications. The spallation target has a large thermal load due to the conversion of about 10 MW proton into a neutron. Therefore, the target needs a cooling system; there are two options that can be considered i.e., cooling by means of the subcritical reactor primary system coolant and cooling by means of an independent loop.