Nuclear Power Plants In The Main Steam Pipe Support Retaining Plate Weld Defects Causes And Countermeasures

Pressurized water reactor nuclear power factory steam pipeline is the steam generator produces the steam to the turbine and its auxiliary equipment, the flow of the system. Used for earthquake condition to jilt and limit of the damper by overall bracket fittings and pipe connection, the whole scaffold fittings is to rely on "flake" plank (sheeting) and tube formation of fillet weld, used to say guard plate weld. A pressurized water reactor nuclear power plant main steam piping material grades for TU48C, refueling overhaul in service inspection detection plate weld defects exceeding many times, due to the expansion of defects, some cracks into the parent metal, affect the structural integrity of the high temperature and high pressure pipeline. Based on the material, welding, computer simulations and related theory and method, for nuclear power factory steam pipe support plate weld defect formation are studied, and on the basis of genetic research puts forward the countermeasures of the defect. Paper main research work are as follows:(1) selecting guard typical main steam pipeline weld defect metallographic compound membrane was carried out, at the same time according to the need of the comparative study from the other units not found defects of the guard plate weld process with metallographic test.(2) in order to study the cause of the defect, select simulate different weld specimens studied structure (the slope Angle of weld and weld slope Angle, fully enclosed and semi-enclosed weld), the process conditions (preheat and heat treatment) of weld residual stress, stress distribution, the influence of joint stiffness.(3) Measurement by blind hole method the simulator under four different conditions of welding residual stress and the method of finite element analysis for plate weld support local stress has carried on the simulation, the influence factors and influence laws are obtained. (4) in the armor plate weld defect based on the study of the causes, combined with engineering practice puts forward the countermeasures of protection plate weld defects repair.