Accelerator Driven Sub-critical System (ADS), where the transmutation of long-life radioactive waste can be carried out, is considered to be the optimum method of converting spent fuel into short-lived isotopes. Currently, ADS has not been built up around the world yet, as it is still in the transitional phase from key technologies tackling to systematic and integrated research. 

As one of the national major science and technology infrastructures, the China initiative Accelerator Driven System (CiADS) will be the world’s first prototype of ADS facility at megawatt level to explore the safe and proper technology of nuclear waste disposal.  

An ADS Research Center in China will be established for exploring the sustainable development of nuclear power in a cleaner, safer and more efficient way with international cooperation, so as to achieve sustainable and peaceful utilization of nuclear energy. 

               CiADS is under construction. (Image by HUANG Xuyi)

Science in CiADS:  

1. We dedicate to High energy, high intensity and high reliability superconducting linear accelerator physics and technologies. 

2. A new generation of high-power neutron source will be derived from the combination of the high-power spallation target and the high energy and high intensity superconducting linear accelerator, promoting fundamental reseach of related neutron science and material science, as well as the neutron technological applications.  

3. The construction of the lead-bismuth-eutectic (LBE) cooled sub-critical reactor will pave the way for R&D of the fourth-generation nuclear power (Generation IV) technologies. 

4. We aim to investigate and prove the coupling operation transmutation techniques of a megwatt ADS. 

Scientific goals: 

The CiADS program is intended to carry out scientific research on the stability, reliability and long-term operations of the superconducting linear accelerator, high-power spallation target and sub-critical reactor core/cladding, and then step by step realize the coupling operation of the whole system from low power to high power. In addition, it is aimed at launching experimental exploration for the transmutation principle of minor actinides and developing the ADS system engineering and control system with independent intellectual property rights, so as to pave the way for the industrial demonstration facility and full-size technological integration in the next stage. 

Project objectives: 

The CiADS program is expected to build up the world’s first high power coupling operation ADS facility at megawatt level (themal power in total ~10 MW), including ~2.5 MW beam power, ~7.5 MW_th reactor power, with more than 24 hours of single full power coupled operation. 

CiADS consists of four major components: 

1. The superconducting proton linear accelerator (sc-Linac), a 350m-long linac, will provide protons at the energy of 250MeV with 2.5MW power. There will be an ion source, a low energy beam transport line, a RFQ accelerator, a medium energy beam transport line, a superconducting accelerator, a high energy beam transport line and a beam dump included. It has a spare room for upgrading to 1.5 GeV. 

2. The high power lead-bismuth eutectic (LBE) spallation target, coupled with the reactor and designed to withstand maximum beam power at 2.5MW, will contain a target body, a linac/target coupling system and the remote operation and maintenance system for replacing the target window. In the meantime, an experimental terminal will be set up to verify a new concept for the high-power spallation target, the gravity-driven dense granular target (DGT), which is proposed as a potential technology for the future industrial ADS facility. 

3. The sub-critical reactor, with lead-bismuth eutectic (LBE) as the coolant, a spallation target window reserved on the reactor roof and a pool-type design main container, can simultaneously achieve the coupling and physical isolation with the spallation target. A passive containment thermal conduction system will be used to ensure the safety of the sub-critical system in the accident conditions.  

4. The experimental terminals will be divided into multiple areas according to different power levels and safety levels. 

Parteners of CiADS project: 

There are four partners, CNNC, IHEP, GNC and HIPS, participating CiADS.