China’s FDS consortium is currently working on projects to develop a family of reactors that use heavy metal as a coolant, Dr Liu Chao of the International Academy of Neutron Sciences in Chongqing told the Sixth International Scientific & Technical Conference on Innovative Designs and Technologies of Nuclear Power (ISTC NIKIET – 2023). During the plenary session of the conference held at Russia’s NA Dollezhal Scientific Research & Design Institute of Power Engineering (NIKIET), Dr Liu explained that neutron sources are the important experimental platform for the R&D of advanced nuclear energy and nuclear technology applications.
High Intensity Steady Neutron Sources (HINEG) have been developed in China with different missions including neutronics design validation, materials and components irradiation testing, nuclear waste burning and nuclear technology applications, etc. HINEG includes three stages: HINEG-I, HINEG-II and HINEG-III.
According to Dr Liu, HINEG-I has produced fusion neutrons with the yield of 6.4×1012 neutrons per second (n/s) at maximum, and has been coupled with a lead-based zero power critical/subcritical reactor named CLEAR-0, which is an accelerator-driven fusion-fission hybrid system. A series of typical experiments have been carried out on HINEG-I, including neutronics and code validation, core physics study of advanced reactors, neutron radiography, neutron detectors calibration, neutron biological effects, neutron radiation hardening, and more.
HINEG-II is ultra-high intensity steady neutron source with designed neutron yield 1013–1015 n/s. It aims for multi-purposes such as radiation damage mechanism study, core physics and advanced reactor technology validation, and neutron application technology research including neutron capture therapy, isotope production. The design and R&D for key technologies of HINEG-II areon-going.
HINEG-III is high flux steady state neutron source with the intensity of 1017–1018 n/s. It will be coupled with a subcritical reactor with neutron flux higher than 1015 n/cm2/s. HINEG-III is a multipurpose neutron irradiation platform to conduct fuel, material and components irradiation testing for advanced reactors. The conceptual design of HINEG-III is on-going.
Liu identified three main reactor projects that are currently under development following on from CLEAR-0 experimental stand – CLEAR-M, CLEAR-A and CLEAR-400. The CLEAR-M reactor design is a compact 35MWt low power reactor that is easy to move and install. The entire installation can operate in the mode of electricity production at a capacity of 14MWe. An alternative use is electric power of 10MWe and heat production from a capacity of 17MWe. The heat carrier is based on lead. In 2018, it was decided that lead would be selected for the CLEAR-M project and its derivatives to postpone a solution to the polonium problem. The fuel is uranium dioxide (UO2) with an average enrichment of 18.5%. the fuel campaign is10-20 years and the temperature of the coolant at the outlet is 495° C.
The CLEAR-400 reactor design is a small modular reactor with lead coolant intended to replace obsolete coal-fired power plants. The reactor power is 400 MWt or 150MWe. The fuel is UO2 with an average enrichment of 19.75% and the fuel campaign is 5-10 years. The temperature of the coolant at the outlet is 480° C.
The CLEAR-A reactor is a subcritical accelerator driven system (ADS). The heat carrier is lead – a metal fuel with zirconium matrix. The reactor is controlled using a proton accelerator at 900 MeV. Dr Liu noted that CLEAR-A will be able to use depleted uranium or thorium as fuel.
While the CLEAR reactors are still in the design stage, experimental stands are already operating. The multifunctional lead-bismuth stand KYLIN-II is used for thermal and material research, as well as to support the creation of key equipment for the reactors. Dr Liu told the conference that the stand had worked for more than 40,000 hours. For testing the components and equipment of the CLEAR reactors there is a non-nuclear stand CLEAR-S with a lead-bismuth loading is 240 tonnes.
The FDS consortium includes over 20 Chinese institutes and organisations. Its tasks include conducting R&D on promising nuclear systems and applications of nuclear technologies. The total number of employees is over 600. The progenitor of the consortium was a research group led by Professor Wu Yingan. In the early 2000s, the group was transformed into the "FDS Team", and in the early 2020s a FDS consortium was established.
Currently, the consortium has four bases for conducting research and R&D:
- Chongqing specialising in neutron physics and nuclear medicine;
- Qindao specialising in neutron physics and promising reactors;
- Nanjing specialising in equipment for radiotherapy; and
- Hefei specialising in neutron physics and industrial safety.
