Towards an Improved Burnup Measurement Equipment for Spent Fuel Assemblies in Belgian Nuclear Power Plants

SCK•CEN is investigating experimental methods to assess their capability for burnup determination of spent fuel elements. This assessment is performed from an operator’s point of view, meaning that certain information like initial enrichment of the fuel element, the irradiation history and material composition can be taken into account for the assessment. The method in use in the Belgian Nuclear Power Plant of Doel is the so-called Fork Detector. The Fork Detector measures the passive neutron and gamma emission of a spent fuel element and can be used for the assessment of the burnup and Safeguards verification activities. An industry sponsored research project is ongoing to develop and validate a measurement system for the accurate determination of the average burnup, axial and radial burnup profile of a spent fuel assembly. Passive Gamma Spectroscopy was considered as the technology to be investigated and evaluated for a possible integration in a “Fork-like” measurement equipment. This paper summarizes the main findings of the projects and the conclusions that have been reached so far on the design of the new measurement device.