Numerical Modelling of Corrections relevant to Nuclear Accountancy Measurements by Hybrid K-edge / XRF Densitometry

Hybrid K-edge densitometry (HKED) is a radiometric technique for the non-destructive assay of U and Pu in different types of Nuclear Safeguards samples such as those encountered in existing spent-fuel Reprocessing Plants. A similar Hybrid K-Edge instrument is ready to be installed at an ITU hot cell for measurements on samples from pyro-chemical, as opposed to traditional, reprocessing of spent fuel. Unlike the low-Z matrices of traditional reprocessing samples, the matrices of pyro-reprocessing samples contain high-Z elements, such as Cd or Bi. To reduce the calibration effort normally needed for accurate routine HKED measurements, and to predict the behaviour of unusual samples, e.g. U-Pu mixtures with unusual element ratios or those with high-Z matrices, a Monte Carlo modelling approach was chosen. As the excitation of U and Pu use different fractions of the incident x-ray spectrum, special attention was given to reconstruct accurately the spectrum of the incident x-ray source used as the excitation source in the HKED instrument. In routine measurement of the U/Pu ratio, samples with similar but slightly different composition or density are analysed. A study of the effect of a sample's composition/density variations on experimentally observed U/Pu fluorescence peak area ratios has been undertaken and evaluated.

TOMA Magdalena;  VAN BELLE Pieter;  LUETZENKIRCHEN Klaus;  SHARIKOV Dmitry; 

2013-12-19

ESARDA

JRC81433

http://esarda.jrc.ec.europa.eu/index.php?option=com_content&view=article&id=70&Itemid=238,    https://publications.jrc.ec.europa.eu/repository/handle/JRC81433,