Contaminated concrete and metal pipework presents a major nuclear decommissioning challenge in terms of the total volumes of material to be treated,the radiation levels present and the number of facilities affected.Un...Contaminated concrete and metal pipework presents a major nuclear decommissioning challenge in terms of the total volumes of material to be treated,the radiation levels present and the number of facilities affected.Until recently,industrial lasers have often been seen as too unreliable for use in nuclear decommissioning environments and hence their usage has been limited.The advent of solid state 'fibre' lasers has,however,provided a robust and reliable industrial tool,capable of performing not only concrete scabbling but other laser based decommissioning processes,such as cutting.Whilst concrete scabbling has been demonstrated in the laboratory,to date,no representative scale demonstration has been provided which would give industry confidence in the technique.This paper will describe the development of a laser scabbling process head,equipped with an integrated debris collection device and adaptive control system for automatic maintenance of the attitude and stand off distance of the head from the concrete surface.The results of using optical fibre delivered laser power to remove the surface of a range of representative and large scale concrete samples will be described.Using 5kW of laser power,removal rates up to 7000 cc of concrete per hour have been recorded at a removal depth of the order 10mm.The paper will also report on the results of using the same laser source,for single-sided cutting of 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.展开更多
文摘Contaminated concrete and metal pipework presents a major nuclear decommissioning challenge in terms of the total volumes of material to be treated,the radiation levels present and the number of facilities affected.Until recently,industrial lasers have often been seen as too unreliable for use in nuclear decommissioning environments and hence their usage has been limited.The advent of solid state 'fibre' lasers has,however,provided a robust and reliable industrial tool,capable of performing not only concrete scabbling but other laser based decommissioning processes,such as cutting.Whilst concrete scabbling has been demonstrated in the laboratory,to date,no representative scale demonstration has been provided which would give industry confidence in the technique.This paper will describe the development of a laser scabbling process head,equipped with an integrated debris collection device and adaptive control system for automatic maintenance of the attitude and stand off distance of the head from the concrete surface.The results of using optical fibre delivered laser power to remove the surface of a range of representative and large scale concrete samples will be described.Using 5kW of laser power,removal rates up to 7000 cc of concrete per hour have been recorded at a removal depth of the order 10mm.The paper will also report on the results of using the same laser source,for single-sided cutting of 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.
