燃料棒加长端塞与包壳管TIG环焊工艺研究  

Study on TIG Girth Welding for the Long Bottom End Plug ofFuel Rods

作　　者：王苹 汪建红 温轲 WANG Ping;WANG Jianhong;WEN Ke(Jianzhong Nuclear Fuel Co.,Ltd.,CNNC,Yibin,Sichuan Prov.644000,China)

机构地区：[1]中核建中核燃料元件有限公司,四川宜宾644000

出　　处：《中国核电》2024年第2期171-175,共5页China Nuclear Power

摘　　要：新型燃料棒采用自主研发的锆合金包壳管,具有独特的长形中空下端塞结构,由于包壳管与端塞配合处壁厚较薄,端塞总长变长,采用常规燃料棒端塞TIG焊接方式将面临焊缝易烧穿、焊缝腐蚀检查不合格、焊接设备工装无法满足要求等问题。通过设计焊接工装和开展焊接电流试验、管内负压试验、夹持距离调整试验,针对新型端塞斜面面积小影响散热效果、焊接变形导致直线度超差问题,重新设计了焊接顶头结构;为避免焊缝熔深过大,选择了合适的TIG焊接峰值电流,并重新匹配焊接基值电流;为保证焊缝腐蚀检查结果合格,焊接前调整包壳管侧夹持距离,焊接过程中对包壳管管内空气进行抽空。采用新的TIG环焊工艺,获得了外观尺寸合格、理化性能优良的焊缝质量,焊接结果满足要求。The new fuel rod adopts the self-developed zircalloy cladding tube,which has a unique long and hollow bottom end plug structure.Due to the wall is thin,and the bottom end plug is long,the conventional TIG girth welding method of the fuel rod end plug will face problems such as easy burning of the weld,failure of the corrosion inspection,and the inability of welding equipment to meet the requirements.The welding tooling is designed.And the welding current test,tube negative pressure test and clamping distance adjustment test are carried out.In view of the small bevel area of the new end plug affecting the heat dissipation effect,welding deformation resulting in excessive straightness,the structure of the welding tooling was redesigned.In order to avoid the excessive welding depth,the appropriate TIG welding peak current is selected,and the welding base current is re-matched.In order to ensure that the weld corrosion inspection results are qualified,the clamping distance of the cladding tube side is adjusted before welding,and the air inside the cladding tube is evacuated during welding.The new TIG girth welding process was used to obtain the weld quality with qualified appearance and dimensional,excellent physical and chemical properties,and the welding results met the requirements.

关 键 词：下端塞 TIG环焊 焊接电流 夹持距离 

分 类 号：TM623[电气工程—电力系统及自动化]