Candu Energy, a member of the SNC-Lavalin Group, has announced it is engaged in pre-project design and engineering work with the Third Qinshan Nuclear Power Co (TQNPC), operator of the Qinshan Phase III Nuclear Generating Station located on the outskirts of Shanghai, in China's Zhejiang province. This involves two phases and will facilitate a 30-year life extension of the two Candu reactors at the site.

As the original equipment manufacturer and steward of CANDU® technology worldwide, SNC-Lavalin was a member of the project team that originally constructed the reactors, which are approaching the end of their initial 30-year design life. TQNPC is undertaking a programme to refurbish the reactors and associated fuel channels.

Assisting TQNPC ahead of the refurbishment work, phase one of SNC-Lavalin's mandate has involved producing engineering input planning, a retube preparation plan, auxiliary services design, and a scope summary for phase two of the work. Phase one, which started in 2021, remains on budget and on schedule, and is nearly complete.

Phase two of the work will see SNC-Lavalin produce technical specifications and renderings for key reactor components, and provide services to assist TQNPC in proceeding with procurement activities associated with the reactor refurbishment. Phase two will allow critical preparatory engineering work associated with the refurbishment to proceed early, while permitting the remaining work to be more accurately scoped. This will enable TQNPC to better plan for the conclusive stage of life extension work, while minimizing disruptions. Phase two work will begin this year and be completed in 2024.

"SNC-Lavalin has a track record of success and a level of expertise with this technology that is truly unmatched," said Joe St. Julian, President, Nuclear, SNC-Lavalin. "We are the only company to have successfully undertaken multiple reactor life extension projects on CANDU® reactors across Canada and around the world – including in South Korea and Argentina. We remain the called-upon leaders in our field for life extension work, in addition to our expertise across the whole nuclear lifecycle. Our capabilities span design and new build, asset management, late life management, as well as decommissioning and waste management."

Qinshan's refurbishment programme is the latest in a series of successful Candu reactor life-extensions carried out by SNC-Lavalin. The company said significant operational experience from these past projects across system engineering, tooling design and supply (including possessing a proprietary fleet of field-proven CANDU tooling systems), training, and field execution are leveraged to optimise outcomes at each successive refurbishment. SNC-Lavalin is currently working on life-extension projects at Canada’s Bruce Power and Darlington NPPs.

Qinshan's reactors came into service on schedule and on budget as did the last seven Candu units built by SNC-Lavalin. They remain two of the best performing reactors in China. The traditional fuel for Candu reactors is unenriched uranium. But their technology's flexibility makes it possible to use other feedstock sources with minimal adjustments- including recycled uranium, thorium and mixed oxide fuels. Qinshan's Phase III has already successfully leveraged this capability, proving a natural uranium equivalent to be successful in one of the reactors.

Units 1 and 2 of Qinshan Phase III – majority owned by China National Nuclear Power – use Candu 6 pressurised heavy water reactor technology. Atomic Energy of Canada Limited (AECL) was the main contractor of the project on a turnkey basis. Construction began in 1997 and unit 1 started up in September 2002 and unit 2 in April 2003.

Candu reactors’ large horizontal calandria vessel features 380 tubes through which cooling water flows at high temperature. Each has two end fittings which allow it to be isolated so fuel can be replaced without having to shut down the reactor. Life extension refurbishment requires this, along with thousands of auxiliary components, to be dismantled.

Image: The Qinshan Phase III Nuclear Generating Station located in China's Zhejiang province (source: SNC-Lavalin)