Importance of nuclear data for neutron resonance densitometry

Neutron Resonance Densitometry (NRD) is a non-destructive analysis method for the determination of the isotopic and elemental composition of an unknown sample. This method is being studied as a possible option to determine the heavy metal content in melted nuclear fuel formed in severe nuclear accidents such as the one occurred at the Fukushima Daiichi nuclear power plants. NRD is based on the well established methodology of neutron time-of-flight (TOF) transmission (NRTA) and capture (NRCA) measurements. The determination of the sample content relies on evaluated nuclear resonance parameters compiled in nuclear data libraries such as JEFF-3.1.1, ENDF/B-VII.0 and JENDL-4.0. In a first part of this contribution the importance of the nuclear data used in the analysis process is investigated. A TOF transmission measurement of a tungsten sample with known sample characteristics performed at GELINA is used to show the possible bias introduced in the NRD analysis using existing nuclear data libraries. In a second part of this contribution, an uncertainty evaluation of the NRD analysis of an uranium sample is carried out based on the available covariance information of the resonance parameter file for 235U and 238U given in the JENDL-4.0 library. An estimation of the limitation of the deduced sample content accuracy caused by nuclear data uncertainties is given.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard