In March 2011 the Fukushima nuclear power stations were severely damaged by the Tōhoku earthquake and tsunami. Three nuclear reactors were without suitable cooling and underwent a catastrophic meltdown. The clean-up and decommissioning has required thousands of scientists across the world to invent, develop and deliver new or improved techniques. Part of the planned decommission process requires the molten nuclear fuel to be removed. However, there is currently very little knowledge about the location and makeup of the fuel debris. The high radiation environments within the reactor buildings have made optical camera systems inoperable. A promising method of visualising and characterising the fuel debris is to use acoustic imaging sonar systems within the reactor buildings. This is because sonar systems are very tolerant to radiation and offer the ability to not only image the shape of fuel debris but also to look inside it. A decommissioning programme can only be advanced once the full nature of the fuel debris is known.
There therefore existed a need for a large scanning system which would allow us to position sonar probes and image simulated uranium fuel debris, nuclear reactor core components and nuclear grade pipework (shown in detail in one of the attached images). This scanning system, which employs the drylin bearings, will allow us to develop new imaging methodologies of nuclear fuel in a safe and adaptable environment.
Snake arm or ophiomorphic robots are currently in use in the aerospace and nuclear industries for visual inspection in tight or restricted access within wing structures or in nuclear reactors where direct human access is not possible due to restricted access and the hazardous environment.