Product Code: ICA10_707

Single-Sided Laser Tube Cutting For Nuclear Decommissioning Applications
Authors:
Ali Khan, The Welding Institute (TWI Ltd); Cambridge Great Britain
Paul Hilton, The Welding Institute (TWI Ltd); Cambridge Great Britain
Presented at ICALEO 2010

An essential part of nuclear decommissioning is to ensure that all the radioactive waste arising during the dismantling process is safely, effectively and economically managed. Although 99% of the radioactivity is associated with the fuel which is removed following permanent shutdown, significantly large infrastructures remain, consisting of various materials, of which a significant portion is metallic tubing of various diameters. These tubes need to be reduced in size to be packaged as nuclear waste. Amongst the available thermal cutting processes for such tubes, is the multi-kilowatt fibre laser, offering high beam quality and power transmission over large distances through optical fibres. As a result of the remote operation, there is no risk of contamination of the high value lasers asset, which can therefore be reused on a number of decommissioning tasks. In this paper, the single-sided cutting capability of a 5kW multi-mode Yb-fibre laser is presented for various 304L stainless steel tubes, of diameter up to 170mm and wall thickness up to 11mm. The results show that with the right optical configuration, it is entirely possible to laser cut tubes from one side, at extremely long and safe standoff distances, if the main objective is simply to sever the tube.