DML, the company known for the maintenance and refitting of Britain’s nuclear submarines and now part of the Babcock International Group, has been awarded a contract by UKAEA for the design, build, and commission of a remote manipulator arm – an illustration of the company’s diversification into the civil nuclear industry.

The articulating arm, or boom, is for supply to the fusion research machine at the EFDA (European Fusion Development Agreement) JET (Joint European Torus) facility in Oxfordshire – the world's largest nuclear fusion facility. Designed for remote operation within the torus vessel, the boom will be used to assist installation and maintenance operations.

The nine metre boom, weighing some 3000kg, will interface with end-effectors, which provide a method of supplying replacement tiles and other components to the existing Mascot servo-manipulator (used to perform their installation during planned maintenance periods). The new boom will be operated in conjunction with the existing one, to increase productivity and allow the maintenance tasks to be performed within a shorter outage period.

The boom will feature five yaw joints along its length, giving each joint a lateral movement of ±120 degrees. Once interfaced with the client's control system, it will offer a high degree of articulation and precise manoeuvrability. Weight and rigidity have been optimised to reduce deflection under load. DML Group will also provide ancillary equipment to aid assembly and commissioning of the systems at the site.

Challenges have included meeting the requirements for weight and deflection as well as the manufacturing techniques required to produce the equipment to the strict specifications involved. DML has integrated design and manufacturing by way of reviews in order to develop the original concept design and provide a solution that not only reduces the risks associated with complex manufacture while maintaining the original intent and level of integrity, but does so while employing weight reduction techniques in order to meet the specification.

Management of the design has been undertaken by DML with the support of a specialist design company for the articulating arm links and joints, and all testing/lifting and ancillary equipment will be designed by DML in Plymouth. Manufacture will take place in DML’s secure nuclear build area, previously used to build equipment for the Vanguard class submarine facility. Manufacture began in May, with planned delivery in the autumn.

For more information, visit www.dmlgroup.co.uk