Improvement and Application of Back Pressure Control Valve and Breathing Valve for Auxiliary Feedwater System in Nuclear Power Plant

  Introduction  The operating pressure of the storage tank of the auxiliary feedwater system (ASG) in nuclear power plant is stabilized within the designed pressure range through the combined action of the back pressure control valve and the breathing valve. Abnormal pressure, overpressure or negative pressure deformation in the storage tank will affect the normal operation of the system and cause the failure of the safety function of the system. The performance of the back pressure control valve and breathing valve is very important. Based on the analysis of the existing problems, the back pressure control valve and breathing valve are improved to ensure the pressure stability of the pressure storage tank.

  Method  According to the actual operation experience, the structure of the back pressure control valve and the breathing valve were compared, and the two kinds of valves were improved from the valve structure, sealing type, etc.

  Results  The performance of the improved equipment was stable and no abnormal phenomena such as over-high pressure alarm occurred during use.

  Conclusion  The improved back pressure control valve and breathing valve have been widely used in practical projects, providing certain identification for the subsequent treatment of similar valve problems.