Automatic capping device is a complex and non-standard equipment,its reliability directly impacts the safety operation of Solid Waste Treatment System( TES) in nuclear power plant. In order to improve the reliability automatic capping device,the equipment function and machine structure are analyzed. And Failure Mode and Effects Analysis( FMEA) method is applied to systematically analyze all possible failure modes and their reliability. Through establishing the FMEA worksheet,all failure causes,failure effects and their severity are analyzed comprehensively. Base on these analyzing results,it is easy to find out the product function design defects and weak links. Finally,through putting forward design prevention and improvement measures in design,the mission reliability of automatic capping device is improved,and most serious failure mode occurrence is avoided efficiently. Thus the safety operation of TES has been guaranteed in technology. Automatic reliability of impacts of impacts operation of Solid Waste Treatment System (TES) in nuclear power plant. Automatic order to improve the reliability of capping device, the equipment function and machine structure was analyzed And Failure Mode and Effects Analysis (FMEA) method is applied to systematically analyze all possible failure modes and their reliability. Through establishing the FMEA worksheet, all failure causes, failure effects and their severity are analyzed comprehensively. Base on these analyzing results, it is easy to find out the product function design defects and weak links. Finally, through putting forward design prevention and improvement measures in design, the mission reliability of automatic capping device is improved, and most serious failure mode occurrence is avoided efficiently. Thus the safety operation of TES has been guaranteed in technology.