As one kind of fast reactor, the Traveling-Wave Reactor (TWR) utilizes depleted uranium with a small amount of enriched uranium/ plutonium which is used to kick off the chain reaction. The TWR can run for decades without refueling or removing any used fuel from the reactor. The most challenging issues on TWR are fuel design, structural material for fuel cladding, core physics process analysis and core physics design. Based on the present technology of fuel and structural material, a new concept named Standing-Wave Reactor (SWR) which is the preliminary stage of the TWR is proposed. The wave of fission would move through the depleted uranium core by fuel transfer in SWR. According to the concept of SWR and the published data of fuel and material, the R&D works on 1500MWt SWR have been performed, which cover the reactor core, reactor structure, process system et.al. The preliminary results confirm the feasibility of SWR. Meanwhile, the design of reactor core and the main systems which is based on the technologies of available pool sodium-cooled fast reactor has been accomplished.

As an important part of advanced fuel cycle R&D, conceptual study of accelerator driven system (ADS) in China started since 1995. In 2000, China Institute of Atomic Energy (CIAE), Institute of High Energy Physics (IHEP) and other institutes started a ten-year project aiming at ADS fundamental R&D on physics and related technologies, which is one item of “Key Project of Chinese National Program for Fundamental Research and Development (973 Program)” in energy domain. In order to get a better understanding of ADS neutronics characteristic, China Fast Reactor Research Center initiates a preliminary R&D program focused on neutronics design of a small lead-bismuth eutectic cooled ADS with fast spectrum. In this program, the reactor core of a 10MW thermal power ADS called CIADS (China Initiative ADS) with MOX fuel has been studied and designed. For generally concerning, CIADS can operate in either subcritical or critical mode. Different parameters, such as target size and position, position that transmutation assemblies are placed have been studied during the design work. Results show that a half size target and one zone loading can meet the needs for a small size ADS. Moreover, some important physical parameters of CIADS, such as k eff , k s , power peak factor and neutron maximum flux density are evaluated. According to the R&D work, it’s appropriate to set the k s of CIADS at 0.96∼0.98.

Traveling wave reactor is a kind of nuclear reactor that can convert fertile material into fissile fuel as it runs using the process of nuclear transmutation. In the ignition stage of traveling wave reactor, the core performance is especially complex, since the fissile fuel and fertile material is put in different regions at the beginning. And the distribution of power density will change severely with burn-up during the reactor operation. It is an important part of the traveling wave reactor study to optimize the design of the ignition stage. In this paper, based on a two-dimensional RZ geometry model, some schemes with different sizes and compositions of the ignition zone, middle ignition zone position design and burnable neutron poison addition are simulated and analyzed. Finally, an optimized core design with multi-zone configuration and burnable neutron poison addition is shown. Some design outlines are introduced for further study.