Abstract From a fatigue point of view, the second most important WWER (Water-Water Energetic Reactor) pressure vessel component (after closure studs) are the primary nozzles. These parts are included in the in-service inspection performed every 4 years when non-destructive testing techniques like ultrasonic, eddy-current and dye-penetration methods are applied. After the determination of the severity of fatigue crack, the progress of initial defects over time can be prevented by repair welding. Purpose determination of values of the eight main mechanical properties of the welded nozzle after major repair, evaluation of statistical data for reliability and recommendations for the maintenance. Study design the examination of the nozzle Du-500 revealed the presence of perpendicular crack on the outside surface in the base metal. The crack in the base metal has an angle of 72° with the horizontal plane which was repaired at normal (T = 20 °C) and elevated (T = 350 °C) temperatures by (i) automatic arc welding under the flux layer AN-42, and (ii) ceramic flux. The analysis was performed with 15 different batches of welded steel specimens and every single parameter each time was established by using 45 repetitions of the test procedure for the same type of specimen. Findings the study describes the specific case of defected nozzle's housing that was made of steel 15Cr2MoVA and after the crack repair along the length of nozzle diameter could potentially be further exploited. Value – the analysis of the welded specimens showed good agreement between the empirical and theoretical curves and can be used in lifetime and fatigue life predictions for WWER pressure vessels still applicable in power generation industry.

中文翻译：

---

修复后的WWER压力容器焊缝效率的统计研究

摘要 从疲劳角度来看，第二个最重要的 WWER（水-水高能反应堆）压力容器组件（在封闭螺柱之后）是主喷嘴。当应用超声波、涡流和染料渗透方法等无损检测技术时，这些部件包括在每 4 年进行一次在役检查中。在确定疲劳裂纹的严重程度后，可以通过补焊防止初始缺陷随时间的发展。目的 确定大修后焊接喷嘴的八项主要机械性能值，评估可靠性统计数据和维护建议。研究设计 对 Du-500 喷嘴的检查揭示了母材外表面存在垂直裂纹。母材中的裂纹与水平面的夹角为 72°，在正常（T = 20 °C）和升高（T = 350 °C）温度下通过（i）助焊剂层 AN 下的自动电弧焊进行修复-42，和（ii）陶瓷助焊剂。对 15 个不同批次的焊接钢试样进行了分析，每次通过对相同类型的试样重复 45 次测试程序来建立每个参数。研究结果描述了由 15Cr2MoVA 钢制成的有缺陷喷嘴外壳的具体情况，并且在沿喷嘴直径长度的裂纹修复后可能会被进一步利用。