China ADS sub-critical experimental assembly—Venus-1 and preliminary experiment

China's accelerator-driven sub-critical system (ADS) sub-critical experimental assembly--Venus-1 and the preliminary experiment is presented. The core of Venus-1 is a coupled one of a fast neutron zone and a thermal neutron zone. The fast neutron zone is at the centre of the core and formed by natural uranium fuel. A fast neutron spectrum field can be produced in the fast neutron zone and used for the transmutation of minor actinides (MAs). The thermal neutron zone surrounds the fast neutron zone and is formed by low-enriched uranium fuel. It is a fission zone. An epithermal neutron zone between the fast neutron zone and the thermal neutron zone can be established for the transmutation of longlived fission products (LLFP). On July 18, 2005, the first fuel element was loaded into the Venus-1 sub-critical assembly and some preliminary experiments about the sub-critical neutronics were performed. The Venus-1 can be driven by an Am-Be source or other steady neutron source (Cf-252, D-D reaction and D-T reaction) to study the effect of the external neutron source with different energies or a D-T pulsed neutron source on the dynamic characteristics.[PUBLICATION ABSTRACT]