Core Viewpoint - The successful breakthrough of the 3rd drainage tunnel at the Fujian Zhangzhou Nuclear Power Project marks a significant step in the construction of this critical infrastructure, enhancing China's capabilities in nuclear power engineering and contributing to national energy security [2][3]. Group 1: Project Overview - The Zhangzhou Nuclear Power Project is a key nuclear power development base for China, with the 3rd and 4th unit drainage tunnels being crucial for cooling water discharge [2]. - The drainage tunnel exceeds 5,200 meters in length, making it the longest underwater tunnel in China's nuclear power sector [2]. - The project aims to establish a replicable standard for deep-sea underground engineering construction, showcasing China's technological strength in the global nuclear power construction field [2]. Group 2: Technical Challenges and Innovations - The geological environment of the 3rd tunnel is complex, presenting challenges such as "soft above, hard below" conditions, leading to frequent wear and replacement of conventional cutting tools [3]. - The project team innovated a tool management method and successfully validated the use of a toothed rolling cutter, enhancing efficiency and safety in tunneling operations [3]. - The team improved mud treatment capabilities by mastering key parameters related to the filter press, significantly overcoming construction bottlenecks [3]. Group 3: Safety and Environmental Considerations - To address high-temperature and high-humidity working conditions, the project team implemented effective measures, including providing cooling supplies and establishing shaded rest areas [3]. - The completed drainage tunnel will discharge cooling water into deep-sea areas, mitigating the impact of seawater temperature rise on coastal environments, thus supporting the operation of two 1,000-megawatt nuclear power units [3]. Group 4: Future Commitment - The project team is committed to leveraging its technical, management, and resource advantages to continue pushing forward with the project while maintaining strict quality and safety standards [4].