Design of a neutron interrogation cell based on an electron accelerator and performance assessment on 220 liter nuclear waste mock-up drums
Résumé
Radiological characterization of nuclear waste drums is an important task for the nuclear industry. The amount of actinides, such as or, contained in a package can be determined using non-destructive active methods based on the fission process. One of these techniques, known as neutron interrogation, uses a neutron beam to induce fission reactions on the actinides. Optimization of the neutron flux is an important step towards improving this technique. Electron accelerators enable to achieve higher neutron flux intensities than the ones delivered by deuterium-tritium generators traditionally used on neutron interrogation industrial facilities.
In this paper, we design a neutron interrogation cell based on an electron accelerator by MCNPX simulation. We carry out photoneutron interrogation measurements on uranium samples placed at the center of 220 liter nuclear waste drums containing different types of matrices. We quantify impact of the matrix on the prompt neutron signal, on the ratio between the prompt and delayed neutron signals, and on the interrogative neutron half-life time. We also show that characteristics of the conversion target of the electron accelerator enable to improve significantly measurement performances.
Mots clés
MCNPX simulation
neutron interrogation industrial facility
deuterium-tritium generator
higher neutron flux intensity
neutron flux optimization
neutron beam induce fission reaction
fission process
nondestructive active method
239Pu amount
235U amount
actinide amount
nuclear industry
nuclear waste drum radiological characterization
nuclear waste mock-up drum performance assessment
neutron interrogation cell design
ionizing radiation
radioactivity
neutrons
instrumentation
nuclear instrumentation
Neutron-gamma discrimination
Electron accelerator
neutron interrogation
nuclear waste drum
photoneutron
uranium
deuterium
electron accelerators
fission
neutron beams
neutron flux
plutonium
radioactive waste storage
tritium
measurement performance
electron accelerator conversion target characteristic
interrogative neutron half-life time
delayed neutron signal ratio
prompt neutron signal ratio
prompt neutron signal
matrix impact quantification
matrix type
uranium sample
photoneutron interrogation measurement
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