China’s State Nuclear Power Engineering Corporation (SNPEC) awarded Emerson Process Management a multi-million dollar purchase order for Fisher control valves to go in Westinghouse AP1000 pressurized water reactors at the Sanmen 2 and Haiyang 2 nuclear power plants in China.
The valves will see use in applications in the plants’ nuclear islands and in their passive residual heat removal system.
In the nuclear containment area, Emerson’s Fisher air-operated control valves will serve several functions related to operational safety.
As part of the safety related system, the valves comply with government requirements, including ASME Section III standards for components of nuclear facilities, and undergo rigorous qualification testing at the Emerson Innovation Center in Marshalltown, Iowa. They size the valves’ actuators in accordance with EPRI (Electric Power Research Institute) guidelines to ensure adequate operating margins that meet industry standards. To confirm they can operate after a seismic event, they undergo tests to see if they can survive 6g (6 times gravity) vibration loads in three axes.
In the passive residual heat removal system, Emerson’s Fisher control valves will help achieve proper plant cooling during shutdown. Engineers at Emerson developed a specially modified ball valve that fits in the limited space available while meeting three key requirements: Highly efficient flow during shutdown to provide cooling through a natural convection process without the assistance of the reactor coolant pump; tight shut-off when the plant is in operation to maintain efficiency; and accurate throttling control for all flowing conditions.