Vogtle milestones

Friday, 26 October 2012

The official start of construction at Vogtle 3 and 4 has drawn nearer with permission for a change in the concrete to be used, while Chinese engineers have agreed to share their experience of AP1000 construction.

The new Westinghouse AP1000 reactors are being built in the US state of Georgia by Southern Company and four other firms that own stakes in the existing two-unit plant. Building two more units simultaneously, the companies have set up module assembly areas and the world's largest heavy-lift derrick crane to move the components into place.

Calling it "the largest job-producing project in Georgia," Southern said 2300 people are working on-site and have so far amassed ten million working hours. Permanent jobs should number 800 when the units begin operation in 2016 and 2017.

Welding work on Vogtle 3's containment vessel, one of many components being prepared. The unit's condensers are already on site and the reactor pressure vessel will arrive in early 2013 (Image: Southern Company)

Foundations for turbine buildings and cooling towers are well advanced, but the official start of construction on the nuclear islands has been delayed by an error concerning rebar in the building basemats. It was found after installation that the rebar possessed a 'hook' length shorter than licensing requirements.

To accommodate this Southern, Westinghouse and construction partner Shaw proposed to regulators that they use a concrete mix rated for higher compressive loads - a mix suitable for 5000 psi instead of 4000 psi. The companies showed that the new mix would meet compressive strength requirements without invalidating any generic analyses on other aspects of its safety performance. A batch of 5000 psi concrete was also tested and qualified at the site.

The Nuclear Regulatory Commission reviewed and accepted the arguments and this week rewrote the pertinent licence conditions. This clears the way for the pouring of first concrete on the reactor buildings, which would mark the official start of their construction.

Chinese connection

 
A cooperation deal was signed today between Shaw and State Nuclear Power Technology Company (SNPTC) that will see the Chinese firm send engineering and technical personnel to the USA. Both firms are working with Westinghouse to build the first four AP1000s at Sanmen and Haiyang. Now the cooperation will be extended with SNPTC staff travelling to Vogtle to "actively use valuable experience gained in China... [and] provide technical support for construction."

SNPTC noted that the deal marked the first time a Chinese nuclear technical services had been contracted to a developed country.

Researched and written
by World Nuclear News