Friction Stir Welding

The Swedish Nuclear Fuel and Waste Management Co. (SKB) has been tasked with managing Sweden's nuclear and radioactive waste. During the almost 40 years since nuclear power has been generated in Sweden, much effort and R&D has been expended on finding a final repository for the waste and a reliable way of encapsulating and sealing the copper canisters of spent nuclear fuel, which must remain intact for some 100 000 years. The copper canisters (5 m long) for spent nuclear waste are cylindrical featuring a 5-cm-thick copper corrosion barrier. The canister, with an outer diameter of 105 cm must be sealed using a welding method that ensures extremely high joint quality.

SuperStir™ Canister Machine
Photo courtesy of Swedish Nuclear Fuel and Waste Management Co. (SKB)

The Friction Stir Welding process was investigated and thoroughly evaluated. SKB decided to order a purpose-built ESAB SuperStir™ Canister machine, which has been in use for several years at the SKB canister laboratory.

Narrow Gap welding


The HNG Multi third-generation welding head has been designed for both Single (AC or DC) and Tandem (DC/AC or AC/AC) wire welding in parallel or almost parallel joints, ranging in width from 18 mm and down to 450 mm in depth.

  • Continuous double-sided joint tracking gives a high reliability at shift overlap
  • Continuous measuring of joint width
  • Short-circuit protected, welding head - workpiece
  • Automatic positioning
  • Possible to weld up to 50 mm joint width
  • Air-cooled torch
  • Reliable and uniform high weld quality
  • High productivity
  • Minimum of supplementary work

HNG Tandem head productivity:

Steam generator   Single-wire process
welding duration
Tandem process
welding duration
Joint No. 1 90 h 50 h
Joint No. 2 90 h 50 h
Joint No. 3
70 h 44 h
Joint No. 4 70 h 44 h
Joint No. 5 60 h 40 h
Joint No. 6 85 h 42 h
Total 465 h 270 h

Potential gain = 195 h

A6-MHW Manhole WelderA6-MHW "Manhole Welder"

  • Equipment designed for welding manholes or nozzles on cylindrical vessels or flat plates.
  • Machine fixed to the workpiece by manual clamping with special jaws to ensure safe constriction to manholes with diameters between 250-460 mm (10-18 in.)
  • Safety clamping beam with tension bar in the cylindrical body to prevent tilting.
  • Rotation device for the welding head.
  • Torch that travels along a rigid rail on a light-weight carriage.
  • Welding head made from A6 components.

Read More:

Narrow Gap Welding

Copper canisters for nuclear waste
Copper canisters for nuclear waste.