AP1000核电机组汽轮机轴瓦具有直径大,巴氏合金层与瓦体结合强度要求高的特点,采用静态浇铸工艺、燕尾槽结构,其燕尾槽部位易产生脱壳、气孔等缺陷.目前国内尚无适合轴瓦的超声检测规程,三菱(MHI)轴瓦验收准则中采用碳钢试块的灵敏度调整方法,简单方便,具有足够的探伤灵敏度;而且不需要专门试块,对在役轴瓦的超声检测很有实用价值,也为国内其他机组的轴瓦超声检测提供了一种思路.对于目前AP1000核电机组的在役轴瓦超声检测,考虑到与设计的一致性及可行性,应采用MHI轴瓦检测标准进行超声检测.

AP1000 nuclear power steam turbine bearing is of large diameter,and its Babbitt alloy layer and the tile body requires to be combined with high strength.Due to the fact of using static casting process and a dovetail groove structure,the dovetail groove position is more susceptible to shelling and defects such as pores.At present there are no available domestic ultrasonic testing procedures for the bearing,but for the Mitsubishi (MHI),it uses carbon steel bearing acceptance criteria for test block sensitivity adjustment method,and is found to be simple,convenient,and effective with enough detection sensitivity.Owing to no need for special test block,the method is of very practical value for in service ultrasound testing of the,and it also offers a way of bearing ultrasonic detection of other units at home.Considering the design consistency and feasibility,for current AP1000 nuclear power units,it is recommended that the in service bearing ultrasonic testing should use the MHI bearing detection standards.