Measurement technique of plutonium and minor actinides using nuclear resonance fluorescence with laser Compton scattering gamma-rays

We have proposed a new nondestructive assay method for 239 Pu in spent nuclear fuel including melted fuels of the Fukushima plants. In our proposed system 239 Pu is measured using nuclear resonance fluorescence (NRF) with a monochromatic gamma-ray beam. Such a gamma-ray beam is generated by Compton scattering of laser photons with high energy electrons. This method has a crucial advantage that we can measure 239 Pu independent of the shape and chemical composition of a melted fuel sample. Two types of backgrounds may affect the precision of the measured quantity of 239 Pu. We estimate the statistical error of expected NRF signals and background originated from radioactivities in the spent fuel. We concluded that it is possible to assay 1% 239 Pu content in a spent fuel with 1.6% statistical precision during the 4000 second measurement time using our proposed system with incident gamma-rays around 5 MeV.