Hydraulic pressure test of containment penetration protection sleeves for Haiyang Nuclear Power Unit 3 in China succeeds on first attempt

Recently, the hydraulic pressure test of the containment penetration protection sleeves for the main steam and main feedwater pipelines of Haiyang Nuclear Power Unit 3 of State Power Investment Corporation (SPIC) Shandong Nuclear Power was completed, with all four sleeves passing the test on the first attempt. The protection sleeves are an important part of the containment pressure boundary and can safeguard the bellows expansion joints under abnormal pipeline conditions.

It is understood that this test was relatively difficult. The sleeves had long been embedded in the containment, the original pipelines could not be damaged, and the on-site space was narrow, making it impossible to install the tooling. To address these challenges, the production preparation project team innovatively adopted the process of "removing the original guard plate + welding flanges to build a pressure chamber," and joined forces with the design institute and equipment manufacturer to form a special team, conducting multiple simulation verifications and reviewing key parameters, ultimately forming an implementable special test plan.

This plan benefited from the accumulation of previous innovation achievements. The special team innovatively proposed and applied the main steam safety valve locking process, breaking through the original technical barriers of the foreign party, avoiding the safety risks of dismantling and suspended mounting of six main steam safety valves, and achieving a win-win situation in safety, quality, and schedule.

From tooling installation, system water filling, and staged pressure increase to pressure-holding monitoring, team members supervised the entire process, strictly implemented nuclear-grade safety and quality requirements, and conducted full-process on-site supervision. The design, construction, and manufacturer parties cooperated efficiently to ensure the steady progress of the test. The success of this key test on the first attempt laid the foundation for the subsequent construction and commissioning of Haiyang Nuclear Power Unit 3.