Korean CANDU refurbishment achieves milestone

Wolsong CANDU 6 refurbishment achieves first full fuel channel replacement, with AECL and KHNP using robotic tooling to renew 380 zirconium-alloy calandria tubes and heavy-water circuits, extending reactor life ahead of Korea's summer demand.

Atomic Energy of Canada Limited AECL has reached an important milestone with the first successful completion in Wolsong, South Korea, of the removal and replacement of calandria tubes, pressure tubes and end fittings in a CANDU 6 nuclear reactor.

"This success marks the first time a CANDU 6 reactor has had all of the fuel channels removed and replaced," says Hugh MacDiarmid, AECL's President and CEO, "bringing us one step closer to completing the project and allowing the Wolsong reactor to continue building on its excellent operating performance record for another 30 years."

AECL developed hundreds of specialized tools and systems, and through contracts to Canadian manufacturers ensured supply, for this first-of-a-kind groundbreaking work. The tools' robotically driven movements are intricate and precise, and designed to be used in a radioactive environment.

AECL began work on the South Korean reactor in June 2009 to replace all 380 calandria tubes, and also pursued an equipment and consulting deal with TEPCO in the region. Each calandria tube is approximately six metres long by 13 centimetres in diameter. Made of zirconium-alloy, the tubes house the reactor's 380 fuel channels. The fuel channels connect to end fittings on each fuel channel assembly to circulate heavy water coolant between the reactor and steam generators.

"We have 170 Canadian employees working in Korea on the Wolsong project, and they are focused on successfully completing their work in a safe, professional, quality manner," said Ramzi Fawaz, AECL Senior Vice-President of Operations. "Their experience gained at Wolsong and successes like the CANDU milestone in China will serve us well in delivering our current and future refurbishment projects."

The next stage of work at Wolsong is to remove the multi-tonne tooling systems and the work platforms supporting them before feeder installation begins. This will be managed jointly by AECL and the client, Korea Hydro & Nuclear Power Company Ltd. KHNP, amid momentum from the UAE nuclear deal for the Korean industry. The reactor is now on track to return to service for Korea's summer peak demand next year.

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