The test was led and organized by the Hainan Project Department of China Nuclear Power Engineering Co., Ltd., which joined forces with the owner, commissioning, supervision, and construction units to form a dedicated team to tackle the secondary loop hydrostatic test. During the test preparation phase, after sandbox simulation and full discussion at special meetings, the team overcame the implementation barriers of pressurization rate execution. During the test, the team conducted hydrostatic tests at above-design pressure on core equipment and piping of the secondary loop, including steam generators, the turbine proper, and connecting pipelines. Given the particularity of the integrated reactor, the secondary loop pressure test was provided withback pressureby the primary side, avoiding fluctuation effects on the OTSG during the secondary side pressurization phase. The entire test was divided into three stages, with 3-7 pressure platforms set for the pressurization process at each stage. The test pressure was 1.3 times the design pressure, with high requirements for pressurization and depressurization rates and certain challenges in execution. All participating parties coordinated vigorously and cooperated closely. Ultimately, all parameters met the design requirements, with no leakage, deformation, or other anomalies, fully verifying the structural integrity and sealing reliability of the secondary loop system.

As the "energy transfer hub" of a nuclear power plant, the secondary loop undertakes the core function of converting the thermal energy generated by the nuclear reactor into turbine power, and its safety is directly related to the overall operational stability of the unit. The success of this pressure test not only eliminated potential risks in the secondary loop system but also created favorable conditions for subsequent key milestones such as turbine rolling and unit load commissioning.