ROBOTIC WELDING | COVER STORY
● The robots will be located behind shielding until the time they are required to weld
● The container will be shielded as much as possible during welding operations (leaving the welded areas unshielded) to further protect the robots
The design of these features has been analysed and verified by Jacobs shielding experts using specialist software and is also underpinned by radiation exposure experiments in Jacobs’ laboratories. The weld inspection robot is fitted with cameras and an eddy current inspection system so operators can see footage of the entire weld from different angles to assess the weld profile. Quality control is also underpinned by data management, with all data and communications protected by a high-grade cyber security system.
Welding flexibility TANICS™ can perform full penetration butt welds with a unique system that can displace oxygen within a cylinder fitted with a single method of entry/exit. This mitigates the risk of root weld oxidation which occurs when using conventional purge techniques on a nuclear container. As a result of this, the risk of failure and expensive re-work is mitigated. The system also allows inspectors to sign off weld inspections without the need to attend the site in person. This reduces costs of travel to site and accommodation and allows verification to take place efficiently without having to wait for individuals to arrive in person. TANICS™ can weld a variety of container diameters and
can perform full and partial penetration butt welds in addition to fillet welds in both the vertical and horizontal orientations. Existing mechanised welding systems (such as Orbital heads) are fixed diameter machines capable of a single weld geometry such as butt welds. If a fillet weld or different diameter is required, then more machines must be purchased increasing costs. The system incorporates several features to assist with
maintenance when the robot is installed, including a grinding assembly located within the cell to maintain the profile of the tungsten electrode; and a capacity of up to
30 metres of welding wire to complete the required number of containers. Currently there are no other systems capable of being deployed on client sites to do this work in a highly radioactive environment.
Qualification and use TANICS™ is qualified in accordance with the European harmonised codes (BS EN ISO 15614-1) and has been dual coded with American Society of Mechanical Engineers (ASME) IX, by an independent UK third-party body. The qualification process used the acceptance criteria PD5500 Cat 1 and Sellafield Build Level 1. As a result, TANICS™ is a Technology Readiness Level (TRL) 8 technology. “The welds produced using TANICS™ were independently
qualified in the UK and Germany and have now been endorsed by specialists from Sellafield Ltd. This shows that the system has the potential to set a new benchmark for automated welding in the nuclear industry,” said Langfields Projects Director Wayne Griffiths. The system has been endorsed by the welding subject
matter expert at Sellafield Ltd and is capable of being deployed to any site to seal nuclear containers reliably to a high acceptance criterion, in doing so this system is capable of sealing containers to meet both transport and 100-year storage requirements. As the nuclear industry increasingly needs to move
and store nuclear fuel material using bespoke containers, TANICS™ offers a number of benefits over existing solutions, including its repeatability, flexibility and efficiency, and it is suitable for transport and long-term storage. Equally importantly, it is a safe, effective and efficient
means of achieving the required quality of weld and avoids putting operators in harm’s way. This innovation, developed to meet the requirements of the UK’s nuclear decommissioning mission, has potential for export to other nuclear markets, supporting the exports and jobs ambitions of the UK’s Nuclear Sector Deal. David Campbell, Technical Manager for Sellafield Ltd,
concluded: “This is an exciting development where a high integrity welding process can be deployed remotely and adapted to suit a variety of container sealing activities and could almost be classed as off-the-shelf.” ■
Far left: A test piece showing the finished weld
Left: Welding in progress using the TANICS™ system
www.neimagazine.com | February 2023 | 27
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