Re-tube tooling platforms set the stage for Unit 2 Refurb

Construction of the Re-tube Tooling Platforms (RTP) has set the stage for removal and replacement of reactor components during Darlington Nuclear Generating Station’s refurbishment of Unit 2.

The massive stand-alone platforms, one on each reactor face, act as hubs for the re-tube and feeder replacement phase — the largest work package of the 40-month project. The work will see major components of the reactor, including pressure and calandria tubes along with end fittings and feeders, removed and replaced with new parts.

The RTPs consist of a major elevating work surface connected to four massive columns that allow the platform to move vertically across the reactor face. Atop the platform, tools, mounted on rails, are able to move horizontally across the reactor face, allowing access to each of the 480 fuel channels. The entire assembly sits on top of the fuelling machine pit.

The tooling platform is operated remotely, from the Re-tube Control Centre in the power plant.

Each RTP weighs about 50,000 kilograms, which means it had to be brought into the reactor vault in pieces and assembled there.

That’s where the full-scale mock-up of the reactor vault, located at the Darlington Energy Complex and used for training purposes, proved its value.

The RTPs were first assembled and disassembled in the mock-up, allowing the team involved to practise extensively before the current work began. The components were then taken to the station and into the vault through the airlock doors, often using high-tech Automated Guided Vehicles or AGVs.

“As always, safety is key,” said Ken Brown, Director of Re-tube and Feeder Replacement. “The team has planned and practised for this work, which meant the learning curve happened at the training facility, not on the reactor face.”

The removal phase of the project is now underway.