压水堆一回路的许多部件都采用焊接结构。这些部件一般都用含有锰、钼、镍的低合金铁素体钢制成。为了减少浸蚀、腐蚀及一回路介质放射性的影响,其表面都用奥氏体不锈铁进行堆焊。堆焊工艺依其形状和可接近性而分别采用手工焊或自动焊。在法国核计划初期,法美原子能公司曾发现过某些部件堆焊层下的铁素体钢上有小裂纹。 Many components of the PWR primary circuit are welded. These parts are generally made of low-alloy ferritic steel containing manganese, molybdenum and nickel. In order to reduce erosion, corrosion and the radioactive medium of a loop, its surface is covered with austenitic stainless steel. Surfacing process according to their shape and accessibility, respectively, by manual welding or automatic welding. At the beginning of the French nuclear program, the French and American Atomic Energy Corps had discovered small cracks in the ferritic steel under the cladding of some components.