Reliability Analysis On Discharge Failure Of Experimental Advanced Superconducting Tokamak

The utilization of fusion energy is one of the most potential solutions to the problem of energy crisis. This has caught up the attention of many countries'governments. Many fusion experimental devices have been constructed or scheduled on the agenda during recent years including the up-to-date biggest collaboration program International Thermonuclear Experimental Reactor. EAST (Experimental Advanced Superconducting Tokamak) is an advanced nuclear fusion experimental device built by the Institute of Plasma Physics, Chinese Academy of Science. It was the first fully superconducting Tokamak in the world.The safety analyses of these fusion experimental devices have attracted the attention of the research community because of the complexity and radiation-involved. Therefore a systematic analysis must be adopted to assure these devices'safety. Many countries have performed systematic analysis on their fusion experimental devices. Take ITER for example, the safety analysis has been doing since the design stage. To assure and elevate the reliability and the safety of EAST, this paper chooses the fault tree analysis which is usually used in the probability safety analysis to do the systematic analysis of the discharge failure of EAST based on the investigation and analysis of the methods of reliability analysis.This paper introduces the FTA method and its analysis steps, then analyses the system function of the EAST. The main fault tree and the sub-fault trees of the cryogenic system were constructed using the probabilistic safety assessment software RiskA which was developed by FDS Team of the Institute of Plasma Physics, Chinese Academic of Sciences. And the qualitative analysis and quantity analyses were proceeded. The sets of the potential failure, the failure rate and the components importance of the cryogenic system was obtained, it could be used to optimize the design.The fault trees constructed in this paper can be used for the future appliance of PSA in the fusion experiment device EAST, and to make reference to the appliance of PSA in ITER and future fusion reactors.