Abstract
This paper will describe recent work conducted in the UK to highlight the potential of applying high
power laser cutting to aspects of decommissioning and dismantling in the nuclear sector. A major driver
for this activity is size reduction of metallic structures, vessels and tubing, with the objective of efficient
stacking of the cut parts for future long term storage. TWI have used a standard 5 kW multi-mode laser
with fibre optic delivery of the beam, to demonstrate techniques for cutting stainless steel tubing, at diameters
up to 150 mm and wall thicknesses up to 7 mm, and various thicknesses of plate materials. Using
specially developed cutting heads, employing long focal length lenses to form the beam, techniques
were developed to allow the cutting of tubes from one side only and without changing the focal position
of the laser beam with respect to the diameter of the tube perpendicular to the incident beam. The latter
means that remote programming of the cutting path becomes much simpler. For cutting plate materials,
special gas nozzle dynamics have produced great tolerance of the cutting process to stand-off distance
(the distance between the surface of the material being cut and the exit of the cutting nozzle). One particularly
interesting method of remote deployment of these cutting techniques is to use ‘snake arm’ robots.
These robots, by nature of their construction, can access areas un-accessible using other techniques.
This of course makes them particularly suited to aspects of nuclear decommissioning,
particularly in what are termed ‘un-structured environments’, where the exact disposition of items encountered
is not known. The paper will also describe the first time a laser cutting head has been installed
on the end of a snake arm robot and the combination used in a simulated nuclear cutting application.
