Experimental Comparison between High Purity Germanium and Scintillator Detectors for Determining Burnup, Cooling Time and Decay Heat of Used Nuclear Fuel

A experimental study of the gamma-ray energy spectra from used nuclear fuel has been performed. Four types of detectors were used to measure spectra from three PWR used fuel assemblies stored at the interim storage for used fuel in Sweden, CLAB: HPGe, LaBr3, NaI and BGO. The study was performed in the context of used fuel characterization for the back end of the fuel cycle in Sweden. Specifically, the purpose was to evaluate the behaviour of the different scintillator detectors (LaBr3, NaI and BGO) and their ability to be used instead of HPGe detectors when determining spent fuel parameters such as burnup, cooling time and decay heat of the used fuel. This paper presents results from the experimental study and an analysis of the capability of the detectors for used fuel characterization. The results shown are important when designing systems for used fuel characterization, e.g. for determining decay heat or fuel parameters concerning safeguards