Oxygen concentration control is one of the critical issues to a lead-based reactor, and oxygen concentration must be in a reasonable range for long term running, i.e. 10-8–10-6wt%, to balance the corrosion of the structural materials and oxide formation in the lead alloy coolant.

In China, the ADS project has been launched by Chinese Academic of Sciences (CAS) for years, and Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences·FDS Team is in charge of the sub-critical reactor, named China LEAd-based Reactor (CLEAR). In parallel, the oxygen control technology was studied strongly for the ADS project.

In 2015, the oxygen control and monitoring system (OCMS) were applied successfully in the KYLIN-II LBE loop, the oxygen concentration was controlled stably at 10-6, 10-7, and 10-8 wt%, respectively, which satisfied the LBE requirement. The accuracy and stability for the oxygen monitoring and control technology have reached to the international advanced level, with improvement of chemical composition, making process for coated electrode and gradient welding process. Up to now, the OCMS in the KYLIN-II loop has been stably operated for several thousands of hours, which provides an important technology support for the development of lead-based reactor.