Fault tree analysis (FTA) is a deductive fault diagnosis

which has been successfully applied in such areas as the assessment of reliability of nuclear reactors and spacecrafts. Currently reverse osmosis (RO) is the most widely used seawater desalination methodology. The decline of both desalination rate and permeate flow rate is considered the most typical type of fault which causes significant loss in the seawater reverse osmosis (SWRO) system. Based on an in-depth analysis of the component structure and operational principle of the seawater reverse osmosis membrane

this paper manages to work out the fault tree of the decline of desalination rate and permeate flow rate. With the help of Boolean algebra

the minimal cut sets and minimal path sets were successfully established

and the analysis of the importance of basic events structure was finally completed. This research provides a set of scientific and practical methods for the construction of the knowledge base in the SWRO fault diagnosis expert system.