Typical Accidents Analysis on the Loss of Flow and External Neutron Source Changing Accidents for A 800 MWth ADS

摘要

In this paper, preliminary safety studies on the 800MWth accelerator-driven system (ADS) proposed by Xi'an Jiaotong university are presented. The system is a pool type facility coupling a proton accelerator with current in the range of 17 to 23mA and a sub-critical core by means of a spallation target. Here, the RELAP5/MOD3.3 code is selected as a base tool and to meet the requirement of ADS analysis, the point kinetics model is modified and the property of lead-bismuth is implemented. The paper focuses on the assessment of its response to the loss of flow events, the former is originated from the failure of the pump and the latter derives from the significant flow blockage at a fuel assembly inlet. The reactivity insertion accidents are caused by the change of the proton beam current. The results show that the safety and criteria are satisfied and the system is tolerant to the loss of flow accidents and proton beam doubled accident and is sensitive to the external neutron changing.