Emerson Process Management has been awarded two multi-million dollar purchase orders from Westinghouse Electric Company for critical control valves to be used in the first two AP1000s of the Sanmen and Haiyang nuclear power plants in China.

The air-operated control valves will serve several functions related to operational safety in the nuclear containment area, and will be used in the passive residual heat removal system.

Engineers at Emerson have developed a specially modified ball valve that fits into the limited space available while meeting Westinghouse’s 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.

The valves will be engineered to comply with government requirements and to meet ASME Section III standards.

Other valves for the Chinese reactors have been ordered from Flowserve Corporation and US-based SPX Corporation. AP1000 squib valves are being manufactured by US-based SPX, and in March Flowserve said it had won a $15 million order for globe and gate valves and its Limitorque actuators for the Sanmen and Haiyang plants.