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Post Irradiation Evaluation (p.i.e) Of Nuclear Fuel Provides Data Used

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Design of Gamma Scanner for Post Irradiation Evaluation Post Irradiation Evaluation (P.I.E) of nuclear fuel provides data used to support the safety cases of the UK’s fleet of Civil Advanced Gas-cooled Reactors (CAGR) to allow continued operation, implementation of fuel enhancements and increased burnup. Investigation of fuel and components at the facilities at Windscale use various different techniques to evaluate the level of wear or corrosion and measure carbon deposition to ensure the safe running of the reactors. An improved gamma scanning rig has recently been developed to increase the system sensitivity and allow enhanced analysis of the data. Examples of Other Techniques Employed CAGR Fuel Element A CAGR element comprises 36 fuel pins held together in a stainless steel support grid and surrounded by a graphite sleeve. The fuel pins consist of UO2 pellets (235U enriched) encased in a stainless steel cladding which acts as a barrier between the CO2 coolant and the fuel/fission products produced during operation. Stainless Steel support structure Metallography Bottle Gas Sampling Visual Inspection Nitrous Oxide Leak Testing Fuel Pin Dimensional Measurements SEM Graphite Sleeve Dimensional Measurements Fission Gas Measurements The New Rig Design Graphite Sleeve Fuel Pin Description of Gamma Scanning Technique A number of the fission products produced during the time the fuel is in the reactor are unstable and decay with the emission of radiation. By scanning along the length of the pin and detecting this radiation it is possible to determine the abundance and location of some of the isotopes present in the fuel. The gamma trace can then give clues to different properties of the fuel such as burn-up, temperature, defects in the fuel or cladding, fission gas release and pellet location. Wall Plug Position Contact: Martin Scott Adam, Technical Lead – Windscale Fuel PIE T. 00 44 (0) 1946 781449 M. 07854229374 E. [email protected]