Final super modules in place at Summer 2

Thursday, 11 August 2016

The final "super modules" have been lifted into place in the containment vessel of VC Summer unit 2, marking a milestone in the construction of the AP1000 reactor.

Summer unit 2's CA03 module is lifted off the assembly pad prior to installation in the containment vessel (Image: SCE&G)

The CA02 and CA03 modules make up the in-containment refuelling water storage tank. The tank, which holds up to 500,000 gallons - nearly 2 million litres - of borated water, is positioned above the reactor, and relies on gravity as the only driving force needed to release water to keep the reactor core cool should the reactor experience an unexpected shutdown.

Safety features relying on the laws of nature, including gravity, natural circulation and condensation, are known as "passive" systems because they do not require operator actions, mechanical equipment or AC power to be deployed.

The CA02 and CA03 structural steel modules are known as super modules because they are too large to transport and require on-site assembly. The CA03 module - assembled from 17 sub-modules - is over 35 metres long, 12 metres tall and weighs about 228 tonnes. The CA02 is about 12 metres tall and weighs over 50 tonnes.

Scana Corporation subsidiary South Carolina Electricity & Gas (SCE&G) and co-owner Santee Cooper are building two Westinghouse-designed AP1000 units at the VC Summer site in South Carolina, where SCE&G already operates an existing PWR unit. Construction began on both units in 2013, with unit 2 expected to enter operations in 2019 and unit 3 in 2020. Westinghouse is the contractor for the construction project, and Fluor is the construction manager.

Two AP1000 units are also under construction at Vogtle in Waynesboro, Georgia and two each at Sanmen and Haiyang in China.

Researched and written
by World Nuclear News