NUCLEAR DECOMMISSIONING | CONFERENCE REPORT


active liquor storage tanks is of interest where the only current option is chemical wash out, he said. Decommissioning is also prompting some other exciting


innovations and the conference delegates heard about a number of technical breakthroughs, among them a novel electrochemical decontamination technology for nuclear facilities. Luke O’Brien, Laboratory Fellow at the National


Nuclear Laboratory (NNL) outlined the approach which was developed for the decontamination of metal. Electrolytically-assisted surface decontamination is being actively explored for the decommissioning of nuclear facilities. One of the key goals for decommissioning is cost reduction and one area being targeted is the amount of intermediate level metallic waste, which exists in complex geometry and a variety of locations. However, relative to the actual thickness of the metal, the actual contamination layer is miniscule, in many cases only 10s of microns. Effectively removing this layer can release a lot of material from its current waste classification. This not only reduces the costs of the disposal of waste by orders of magnitude, but also can be done in situ, removing hotspots and reducing reliance on more expensive remotely commissioning approaches. The approach is based around using suitable electrolytes and the application of an electrical current to effectively oxidise the surface of the metal which dissolves into the electrolyte. The dissolved metal can then be precipitated out of solution and converted into a grouted waste form. “Every 1000 m² of


waste treated would only generate 1 m³ of effluent. In fact, we possibly generate less,” O’Brien said, concluding: “We believe that we can make substantial savings, both in terms of reducing the costs associated with decommissioning, but also the final waste volumes.” Simon Delavalle, Chief Technical Officer, Veolia Nuclear Solutions UK, also gave a presentation on a robot arm developed for remote investigation of fuel debris in Japan’s Fukushima Daiichi unit 2. The Primary Containment Vessel Investigation (PCVI) system, which consists of a robotic arm with a 21m reach that can gain access to the PCV through a port with a diameter of just 550 mm. Designed to work in a high radiation environment of up to 1000 Gy/h full of obstructions and debris. The arm, which has 18 axes of motion, will investigate and characterise the PCV area, including the pedestal floor and fuel debris zone using a 3D laser scanner, gamma scanner and structured light sensor, as well as using the bespoke actuator capable of gripping, shear cutting and water jet cutting. Deployment of the arm is the first step in the Fuel Debris Retrieval campaign which is an International Research Institute for Nuclear Decommissioning (IRID) project supported by METI funds. Operations with the force feedback, long distance teleoperations manipulator are scheduled to start late in 2022 on behalf of MHI. Following the success of this virtual event, NEI is hosting


its third Small Modular Reactor conference this September. For more information see: https://pmi-live.com/events/ small-and-advanced-reactors2022/ ■


Pipeline Decommissioning and New Connections


DECOMMISSIONING OF PIPES, DUCTS OR CHAMBERS


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www.neimagazine.com | July 2022 | 29


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