This title appears in the Scientific Report :
2015
Thermal neutron Die-Away-Time studies for P&DGNAA of large samples at the MEDINA facility
Thermal neutron Die-Away-Time studies for P&DGNAA of large samples at the MEDINA facility
In Germany, radioactive waste with negligible heat generation has to pass through a process of quality checking in order to check its conformance with national regulations prior to its final disposal. Additionally to the radioactive components in radioactive waste, the waste may contain non-radioact...
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Personal Name(s): | Mildenberger, Frank (Corresponding Author) |
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Mauerhofer, Eric | |
Contributing Institute: |
Nukleare Entsorgung; IEK-6 |
Published in: | 2015 |
Imprint: |
2015
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Conference: | 25th Seminar on Activation Analysis and Gamma Spectroscopy, Aachen (Germany), 2015-02-22 - 2015-02-24 |
Document Type: |
Conference Presentation |
Research Program: |
Helmholtz Interdisciplinary Doctoral Training in Energy and Climate Research (HITEC) Nuclear Waste Management |
Publikationsportal JuSER |
In Germany, radioactive waste with negligible heat generation has to pass through a process of quality checking in order to check its conformance with national regulations prior to its final disposal. Additionally to the radioactive components in radioactive waste, the waste may contain non-radioactive chemically toxic substances that can adversely affect human health and pollute the environment, especially the ground water [1]. An experimental research facility named MEDINA-facility (Multi Element Detection based on Instrumental Neutron Activation) which is based on Prompt- and Delayed-Gamma-Neutron-Activation-Analysis (P&DGNAA) is developed at the Forschungszentrum Juelich GmbH in cooperation with the RWTH Aachen University. The MEDINA-facility uses a 14 MeV pulsed neutron generator and is developed for the qualitative and quantitative determination of non-radioactive, toxic elements and substances in 200-l steel drums [2]. IntensionIn the past, only one gamma-ray spectrum, the prompt gamma-ray spectrum including a content of delayed gamma-ray lines was measured between the two neutron pulses of the neutron generator. For more information out of one measurement, two digital delay generators are used to take fully differentiated prompt and delayed gamma-ray spectra. An optimization of the instant of time for the prompt and the delayed measuring intervals is necessary and realized with the determination of the thermal neutron die-away-time. With the specific thermal neutron die-away time it’s possible to shift the measurement interval of the delayed gamma spectrum in an efficient time interval where the thermal neutron field is almost died-away and the counts of the prompt gamma-ray lines are below the limit of detection. Measurements & ResultsIn this study the determination of the thermal neutron die-away-time of large samples with the MEDINA-facility is presented. This value is needed for the optimization of the prompt and delayed measurement windows between the neutron pulses. The neutron-die-away-time is determined for the empty measurement cell of the MEDINA-facility, an empty 200-l steel drum, a steel drum filled with concrete cylinders and a steel drum filled with PE cylinders. [1 ]Management of low and intermediate level radioactive wastes with regards to their chemical toxicity; IAEA-TECDOC-13525; International Atomic Energy Agency IAEA; December 2002[2] E. Mauerhofer, A. Havenith (2014) The MEDINA facility for the assay of the chemotoxic inventory of radioactive waste packages, J Radioanal Nucl Chem DOI 10.1007/s10967-014-3210-2 |