All non-destructive testing of the nuclear island main coolant piping and surge lines for Haiyang Nuclear Power Units 3 and 4 has passed inspection.

Recently, the Haiyang Nuclear Power Project—undertaken by China Nuclear Industry Fifth Construction Co., Ltd. (CNI5)—achieved another milestone: the final weld joint of the Unit 4 surge line passed ultrasonic testing (UT). This marks the successful completion of all stages of non-destructive testing (visual, liquid penetrant, radiographic, and ultrasonic) for every weld joint on the main coolant loops and surge lines of Units 3 and 4, with a 100% first-pass acceptance rate. The successful conclusion of this critical piping inspection task demonstrates the project's exceptional engineering quality and comprehensive process control capabilities, laying a solid quality foundation for the subsequent commissioning and operation of the units.

Both the main coolant loops and surge lines are classified as "Nuclear Class 1" piping systems within the nuclear island, requiring identical welding processes, methods, and welder qualifications. Consequently, technical preparations for both tasks were conducted concurrently. Adhering to the philosophy of "getting it right the first time," the project leveraged Party-building initiatives to drive key breakthroughs. "Party Member Assault Teams" were established to tackle the most challenging aspects of construction, with key personnel personally overseeing every step of the process. Simultaneously, a "Main Loop Installation Task Force" was formed; supported by a team of technical experts, they overcame process bottlenecks, standardized construction practices, and created welding benchmarks to guide and elevate overall quality. Regarding talent development, the project utilized practical training platforms to facilitate mentorship by master welders—combining theory, simulation, on-the-job shadowing, and hands-on practice—to ensure a steady supply of highly skilled welding talent for nuclear power construction.

Moving forward, CNI5 will continue to be guided by Party-building principles, strictly uphold the bottom line of nuclear safety, deepen whole-process quality control, steadily advance construction, and strive to build a world-class nuclear power project, thereby contributing to national energy security and the "Dual Carbon" strategy.