Cumbria-based company James Fisher Nuclear (JNF) announced on 13 March that it had won a major contract from EDF-Energy to produce inspection tools that will use innovative eddy current technology to assess the condition of the graphite cores across their fleet of nuclear reactors to a level that has not previously been possible.

The Eddy Current Inspection Tools (ECIT), developed by JFN in collaboration with EDF-Energy, Serco (now Amec), Bloodworth Consultancy and Manchester University are designed to assess the condition of the graphite within vacated fuel channels by applying an electromagnetic field to the graphite. As graphite is electrically conductive eddy currents are induced in the material from which the electrical conductivity can be measured and graphite density inferred. Understanding the density variations within each reactor on such a short turn around provides significant support to the safe operation of the reactor fleet. The enhanced understanding of graphite density also enables EDF Energy to improve the assessment of station lifetimes.

Project Lead for JFN Sarah Town said: “We originally developed a Proof of principle Eddy Current tool with EDF-Energy which led to the Prototype Eddy Current Inspection Tool. The prototype was only intended for a limited number of deployments but has exceeded expectation and now, several years later, is still providing EDF with valuable inspection information from within the graphite channels of their reactors.”

The ECIT devices have since been further developed to be robust and adaptable enough to provide reliable and accurate data in the hostile and highly radioactive environment of the reactor cores of EDF-Energy’s fleet of operating AGR nuclear power stations. The data from each inspection is relayed to operators on the charge face and enables rapid assessment of the condition of the core by the EDF-Energy inspection team.

Production will begin at JFN’s modern engineering facility within weeks and the first full deployment will be completed during 2018. The new contract includes control consoles, specialist strongback for transportation and storage and a calibration unit for each tool. Two test rigs have also been commissioned to conduct the Factory Acceptance Tests (FAT) and Temperature Controlled Calibration Tests (TCCT) to ensure that, once manufactured, the ECIT tool will function as expected when deployed on station.