South Korean reactor Wolsong 1 returned to full power on 18 July after an outage lasting 839 days. It marks the first that a CANDU 6 reactor has been successfully dismantled, retubed and restarted, Atomic Energy of Canada Limited (AECL) and Korea Hydro & Nuclear Power Company Ltd. (KHNP) said in a statement.

“This final milestone in the Wolsong 1 Retube Project represents the culmination of an enormous effort by KHNP and AECL to safely retube the reactor and to ensure successful operations going forward,” said Hugh MacDiarmid, AECL President and CEO. “AECL ramped up its capabilities in Wolsong, applying lessons learned from other retube projects, and ultimately proving the future commercial viability of the CANDU retube business.”

The Wolsong reactor retube outage was completed in 839 days, during which KHNP conducted various refurbishment activities. These included removing and replacing all 760 reactor feeders (for a CANDU 6 design) as well as 380 fuel channels and 380 calandria tubes. Remote-controlled tools and massive, highly shielded machines were required to conduct the work safely inside the reactor due to the highly radioactive environment.

Also in 2011, AECL completed its work on a CANDU reactor (Bruce A, Unit 2) at the Bruce Power Generating Station in Ontario, Canada. AECL is nearing completion on its Bruce A, Unit 1 retube and work at the Point Lepreau Generating Station in New Brunswick, Canada is currently on track to meet its revised schedule.