CKDH Series Class 1E, Category K3 multi-turn nuclear-grade valve electric actuator is a core driving device independently R&D by Yangzhou Hengchun Electronics Co., Ltd. for the nuclear power field. Installed outside the containment vessel of nuclear reactors, it can operate stably under normal working conditions and SL2 safe shutdown seismic load, with a design life of 40 years, fully meeting the stringent requirements of nuclear power process systems.
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CKDH Series
The CKDH Series Class 1E Category K3 Nuclear-Grade Multi-turn Valve Electric Actuator is a valve driving device independently developed by Yangzhou Hengchun Electronics Co., Ltd. for nuclear power plant applications. It is installed outside the reactor containment vessel and is designed to operate under normal plant conditions and SL2 safe shutdown seismic loads. The actuator uses a worm gear mechanical transmission with a 380V three-phase AC motor and is suitable for gate valves, globe valves, and other linear-stroke valves in nuclear island auxiliary systems, conventional islands, and safety-related auxiliary systems. The design life is 40 years.
The actuator is certified as Seismic Category I and is designed to withstand SL2 safe shutdown seismic loads while maintaining operability during design basis events. It is rated for cumulative gamma irradiation up to 110×10³ Gy over the design life, supporting installation in areas with elevated radiation levels outside containment.
The 40-year design life aligns with the operating cycle of nuclear power plants. Core components include a ZL111 aluminum alloy gearbox housing, a 20CrMnTi alloy steel worm, and a QAl10-4-4 aluminum bronze worm gear. These materials are selected for mechanical strength, wear resistance, and dimensional stability under long-term nuclear plant operating conditions. Each unit undergoes factory inspection before shipment.
The actuator has an IP68 protection rating, providing dust-tight and continuous immersion protection for humid and dusty nuclear plant environments. A disc spring assembly combined with a torque control mechanism provides overload protection, stopping the motor when torque exceeds the set threshold and protecting the valve and actuator from mechanical damage.
The modular architecture supports efficient on-site installation and commissioning. Components can be disassembled and replaced individually, which reduces maintenance time and downtime during scheduled outages. The actuator outputs torque directly; thrust output for rising-stem valves can be achieved through a dedicated conversion device.
Parameter Category | Specific Parameters |
|---|---|
Product Type | Multi-turn nuclear-grade valve electric actuator |
Nuclear Safety Classification | Class 1E electrical safety rating; Category K3 seismic classification; Seismic Category I certification |
Design Life | 40 years |
Protection Rating | IP68 |
Power Supply | 380V three-phase AC |
Transmission Structure | Worm gear mechanical transmission |
Output Form | Torque output (thrust output via conversion device) |
Applicable Valves | Nuclear power gate valves, globe valves, and other linear valves |
Seismic Resistance | Withstands SL2 safe shutdown seismic load |
Irradiation Resistance | Withstands 110×10³ Gy cumulative gamma irradiation |
Operating Conditions | Stable operation under normal working conditions and safe shutdown conditions |
Overload Protection | Disc spring assembly + torque control mechanism |
Core Materials | ZL111 gearbox housing, 20CrMnTi worm, QAl10-4-4 worm gear |
Processing | Precision machining with in-process inspection |
Design Feature | Modular architecture |
Installation Location | Outside nuclear reactor containment vessel |
The CKDH Series is designed and tested in accordance with IEEE 382-2019 (Standard for Qualification of Safety-Related Valve Actuators) and RCC-E Chapter A5000 (electrical equipment for nuclear power plants). The manufacturer operates under an ISO 9001 quality management system. Each unit undergoes factory testing including torque verification, seismic simulation, and IP68 protection performance testing before shipment.
Production follows documented nuclear-grade manufacturing procedures with traceable material records. The worm and worm gear are precision-machined and inspected for dimensional conformity. Final assembly includes functional testing of the torque control mechanism, position indicator, and electrical connections. Test records are retained for each serial-numbered unit.
The actuator drives gate valves and globe valves in cooling, feedwater, and drainage circuits of nuclear islands. It maintains operation under SL2 seismic loads, supporting the reliability of auxiliary systems during normal and safe shutdown conditions.
In conventional islands, the actuator is used on steam, feedwater, and condensate water process pipelines. Its IP68 protection and radiation resistance accommodate the humid, warm, and potentially contaminated environment of conventional island facilities.
For emergency cooling and pressure relief systems, the actuator responds to valve open and close commands under safe shutdown conditions. The overload protection mechanism prevents damage to safety-related valves during actuation transients.
The actuator is suitable for valves on water, steam, and other nuclear-grade process medium pipelines. It is designed for continuous long-term operation in the elevated-temperature and elevated-radiation environments found outside reactor containment.
It is adapted to linear-stroke valves in nuclear power plants, primarily gate valves and globe valves. Thrust output can be provided through a dedicated conversion device for valves requiring thrust rather than torque.
It is certified as Seismic Category I and designed to withstand SL2 safe shutdown seismic loads. It is rated for cumulative gamma irradiation up to 110×10³ Gy over the 40-year design life.
The actuator is designed and qualified per IEEE 382-2019 and RCC-E Chapter A5000. Manufacturing follows an ISO 9001 quality management system with serial-numbered traceability and factory test records.
As the original manufacturer, Yangzhou Hengchun provides technical support, on-site commissioning, and maintenance services for the CKDH Series. Support is structured to match the 40-year design life and the scheduled outage cycles of nuclear power plants.
