Sample Thickness Effect on Nuclear Material Quantification with NRTA for Particle Like Debris of Melted Fuel

A method to quantify the amount of uranium and plutonium in melted fuel derived from a nuclear accident such as the one occurred at the Fukushima Daiichi nuclear power plant has not been established yet. For this reason, neutron resonance densitometry, combining neutron resonance transmission analysis and neutron resonance capture analysis, is proposed and its feasibility study has been defined in a collaboration between Japan Atomic Energy Agency (JAEA) and Joint Research Center, Institute for Reference Materials and Measurements (JRC- IRMM). Within this contribution, transmission experiments using three Cu metal disks with different thickness of 0.125 mm, 0.25 mm, and 0.7 mm were made between November 2012 and February 2013 at the Geel Electron LINear Accelerator (GELINA) to investigate sample thickness effect on neutron resonance transmission analysis. We experimentally derived the areal density for the individual Cu samples with the resonance shape analysis code REFIT, and then compared them with the declared areal density. It was found that the REFIT-evaluated areal density was consistent with declared ones for each sample.