Pneumatic-Hydraulic Actuator for Main Steam Isolation Valve and Main Feedwater Isolation Valve
On November 16, 2022, it passed the prototype appraisal organized by China Machinery Industry Federation and China General Machinery Industry Association. The appraisal opinion states: The developed pneumatic-hydraulic actuator for main steam isolation valve and main feedwater isolation valve fills a domestic technological gap and possesses independent intellectual property rights. All performance indicators meet the advanced international standards for similar products. Some indicators surpass those of foreign counterparts, achieving an internationally leading level. It is recommended for application in Hualong One and other nuclear power units.
Scientific and Technological Achievement Appraisal Certificate
(1) Main Technical Parameters
a. Main Technical Parameters of Main Steam Isolation Valve Pneumatic-Hydraulic Actuator
Product Name: Main Steam Isolation Valve Pneumatic-Hydraulic Actuator
Product Model: 400QYZ01
Cylinder Bore: 400(16")
Actuator Closing Force: >1265 kN
Stroke: 670mm
Fast Closing Time: 1s~5s
RCC-E Quality Qualification Grade: K3ad
Control Circuit: Three-train, normally energized
Seismic Category: Category I (Operability) (6g, 6g, 6g)
Service Life: 60 years
Natural Frequency: >33Hz
b. Main Technical Parameters of Main Feedwater Isolation Valve Pneumatic-Hydraulic Actuator
Product Name: Main Feedwater Isolation Valve Pneumatic-Hydraulic Actuator
Product Model: 280QYZ01
Cylinder Bore: 280(11")
Actuator Closing Force: >607.2kN
Stroke: 370mm
Fast Closing Time: 1s~5s
RCC-E Quality Qualification Grade: K3ad
Control Circuit: Two-train, normally de-energized
Seismic Category: Category I (Operability) (6g, 6g, 6g)
(2) Scope of Application
The pneumatic-hydraulic actuator features high reliability, fast closing action, and large thrust. It is widely used in main steam isolation valves and main feedwater isolation valves of pressurized water reactor nuclear power plants, and such actuators are key valve components in PWR nuclear power stations. Under unit accident conditions, the valve needs to be quickly isolated (closing time ≤ 5s) to cut off the main steam and main feedwater flow, ensuring unit safety.
(3) Achievement Application Status
Based on the pneumatic-hydraulic actuators for main steam isolation valves and main feedwater isolation valves, Dalian Dago signed a procurement contract with China General Nuclear Power Engineering Co., Ltd. (CGN E) in 2021 for LOT190D main steam isolation valves and full-load isolation valves for Units 5 and 6 of the Lufeng Project, with delivery expected to be completed this year.
In 2023, a contract was signed with CGN E for LOT190D main steam isolation valves and full-load isolation valves for Units 5 and 6 of the Fangchenggang Project. In 2024, contracts were signed separately with CGN E for LOT190D main steam isolation valves and full-load isolation valves for Units 1 and 2 of the Zhaoyuan Project, and for LOT190D main steam isolation valves and full-load isolation valves for Units 3 and 4 of the Taipingling Project, totaling 54 sets.
Currently, only Dalian Dago and China Nuclear Suzhou Valve have independently developed pneumatic-hydraulic actuators for main steam isolation valves and main feedwater isolation valves in China. The successful research and development of this achievement has broken through the technical bottleneck of domestic pneumatic-hydraulic actuators for main steam isolation valves and main feedwater isolation valves, and is qualified for application in CAP1400, CAP1000, and AP1000 nuclear power units. This is not only significant for achieving 100% localization of CAP1400 third-generation nuclear power plant equipment, but also can promote the CAP1400 independent nuclear power brand to go global and gradually enter the international market.
(4) Intellectual Property Status
The intellectual property achievements independently developed under this project for the pneumatic-hydraulic actuators for main steam isolation valves and main feedwater isolation valves. Through domestic and international patent search and analysis, no blocking patents were found. The intellectual property achievements of the project are independent and controllable. One utility model patent has been applied for ("A Hydraulic Control System for a Pneumatic-Hydraulic Actuator") and has been granted. Three invention patents have been applied for ("Pneumatic-Hydraulic Actuator for Main Steam Isolation Valves in Nuclear Power Plants", "Pneumatic-Hydraulic Actuator Suitable for Main Steam Isolation Valves", "Hydraulic Control System for Pneumatic-Hydraulic Actuator") and have been granted. One paper was published in the "Mechanical Engineer" magazine: "Structural Optimization and Stress Analysis of Pneumatic-Hydraulic Actuator Based on Modal Analysis".
Photographs of Main Steam Isolation Valve and Main Feedwater Isolation Valve Pneumatic-Hydraulic Actuators
Edited by: Li Yuhang
Checked by: Xia Yuanhong
Approved by: Wang Shuai
Department: Technology Development Department
Date: 2025-06-07