Application of LaBr3 detector for neutron resonance densitometry

A method to determine the amount of nuclear materials in melted fuel resulting from a nuclear accident such as the one occurred at the Fukushima Daiichi nuclear power plants has not yet been established. The problem is complex due to the expected presence of 10B and other strong neutron absorbing impurities. For this reason, neutron resonance densitometry, combining neutron resonance transmission analysis and neutron capture analysis, is proposed and a feasibility study has been defined. In this contribution a method to account for the presence of 10B is presented and investigated. The study includes GEANT4 simulations to study the performance of a new well type gamma-ray detector based on LaBr3 scintillators. In the design of the detector the main emphasis was on the capability to separate the full energy peak corresponding to the 478-keV gamma ray resulting from the 10B(n,αγ) reaction from the contribution of the 662-keV gamma ray due to the decay of 137Cs. In addition, experiments have been carried out at the time-of-flight facility GELINA of the EC-JRC-IRMM to test the capabilities of a LaBr3 detector for NRCA applications, in particular to determine impurities present in the melted fuel. A neutron resonance capture gamma-ray experiment with a natSe sample was performed using a LaBr3 scintillator in parallel with a Ge-detector. The results of these measurements demonstrate that a LaBr3 detector is suitable for NRCA as a part of neutron resonance densitometry.

TSUCHIYA H.;  HARADA Hiroshi;  KOIZUMI M.;  KITATANI F.;  TAKAMINE J.;  KURETA M.;  IIMURA H.;  BECKER Björn;  KOPECKY Stefan;  SCHILLEBEECKX Peter; 

2014-12-14

ESARDA and the Joint Research Centre of the European Commission

JRC84084

https://esarda.jrc.ec.europa.eu/index.php?option=com_jifile&filename=YmM0OGViOThkZGQ2YmUzMzUzMzg4OTE2YWQ0Zjc0YzU=,    https://publications.jrc.ec.europa.eu/repository/handle/JRC84084,