Browsing by Author "Kirk, Simon"
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Item Open Access Laser cutting and welding tools for use in-bore on EU-DEMO service pipes(Elsevier, 2018-03-08) Keogh, Keelan; Kirk, Simon; Suder, Wojciech; Farquhar, Iain; Tremethick, Tristan; Loving, Anthony B.Replacement of blanket modules and divertor cassettes in the EU-DEMO will require rapid removal of hundreds of service pipes during maintenance downtime. Duration analysis of conventional joining processes, estimates cutting and welding would account for ∼60% of EU-DEMO remote maintenance. To minimize duration, laser cutting and welding tools have been developed for use within these pipes. The tools consist of a mechanical system to position the tool and the pipe correctly, and a miniaturized laser optics package to apply the process around the entire pipe circumference. Prototypes of the optics for the cutting and welding tools were produced, and the laser processing performances were assessed. Here, we will present the concept and prototype designs of the laser cutting and welding tools, the results of the prototype tool trials, and how the tools fit within the overall remote maintenance strategy for EU-DEMO, these results highlight the duration reduction of a laser process compared to conventional techniques, and the feasibility of a such a design for further development.Item Open Access Laser welding of fusion relevant steels for the European DEMO(Elsevier, 2018-03-30) Kirk, Simon; Suder, Wojciech; Keogh, Keelan; Tremethick, Tristan; Loving, Anthony B.The construction and maintenance of the European DEMO will require reliable joining of thick-walled Eurofer97 steel cooling pipes between in-vessel components in the reactor. To this end, laser welding has been investigated as a potential method for pipe joining. Two different techniques (keyhole laser welding and hybrid laser-laser welding) were used to produce test welds in Eurofer97 and P91 steel samples. Welds were also produced using different filler wires to reduce the hardness in the weldment region and improve the weld profile. Optical microscopy and hardness mapping were used to assess the quality of the welds produced. From the weld trials, suitable process parameters were identified that resulted in fully penetrated welds with good profiles. Here, we will present the results of the laser welding development process and the properties of the welds produced using these two techniques.