Passive and Active Correlation Techniques for the Detection of Nuclear Materials

Deyglun, Clement; Carasco, C.; Pérot, B.; Eléon, C.; Sannié, Guillaume; Boudergui, Karim; Corre, Gwenolé; Konzdrasovs, Vladimir; Normand, S.; Pras, Philippe

doi:10.1109/tns.2014.2315714

Cited by 10 publications

(3 citation statements)

References 19 publications

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“…The low density of the metallic matrix represents an average value for a drum containing metallic components occupying a small volume. A 5 cm thick lead screen surrounds the drum to limit the gamma-ray flux coming from radioactive decays of Pu and 241 Am and reaching the detectors, compared to the 10 cm thick lead screen considered in previous work [6,7]. The detection system is composed of 19 plastic scintillators, as shown in Fig.…”

Section: Numerical Simulationmentioning

confidence: 99%

“…Note that plastic scintillators with PSD capabilities have been recently developed and used in safeguards applications [4,5], but as for liquid scintillators, their use for PNCC of radioactive waste packages would require a large number of small detectors, making again the system costly, and would also be limited in terms of count rate (to maintain acceptable PSD features). Our previous work has shown that plutonium could be measured by PNCC in 118L technological, metallic waste drums using basic EJ-200 plastic scintillators, without PSD capability, but shielded by 10 cm of lead [6,7] to protect against most of the gamma rays coming from the waste. A characterization of cross-talk occurring in these plastic scintillators has also been presented, showing that most of cross-talk-induced coincidences imply two pulses separated by less than 20 ns and 20 cm between neighbor detectors.…”

Section: Introductionmentioning

confidence: 99%

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Passive Neutron Coincidence Counting With Plastic Scintillators for the Characterization of Radioactive Waste Drums

Simony

Pérot

Carasco

et al. 2017

IEEE Trans. Nucl. Sci.

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This paper reports a feasibility study, performed by numerical simulation with MCNPX PoliMi v2.0, for plutonium quantitative assessment in radioactive waste packages by passive neutron coincidence counting with plastic scintillators. Owing to their low cost and good detection efficiency for fast neutrons, plastic scintillators could indeed constitute a good alternative to 3 He proportional counters, which have become too costly because of 3 He global shortage. However, their highsensitivity to gamma rays and cross talk are well-known drawbacks that need to be carefully studied. A measurement system for 118 L drums filled either with metallic or organic technological wastes has been modeled with MCNPX PoliMi, and output data have been processed with ROOT. A 5 cm thick lead shield is used in front of the detectors to attenuate plutonium and americium gamma radiation. In the studied cases, triple coincidences due to 240 Pu spontaneous fissions represent more than 85% of the total signal when using cross-talk rejection algorithms, the 15% remaining coincidences being due to parasitic coincidences caused by (,n) reactions or Am and Pu gamma rays. Although cross-talk rejection significantly reduces counting statistics, a few thousand triple coincidences are still recorded for 1 g of Pu homogeneously distributed in both metallic and organic matrices in a 25 min acquisition. For higher masses of Pu, a linear evolution of the number of coincidences with the mass is observed up to about 10 g. In addition, a study of Pu localization effects has shown that the triple coincidence difference is smaller than 20 % between a point-like fission source and the homogeneous distribution in the drum.

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Section: Numerical Simulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Passive Neutron Coincidence Counting With Plastic Scintillators for the Characterization of Radioactive Waste Drums

Simony

Pérot

Carasco

et al. 2017

IEEE Trans. Nucl. Sci.

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“…The Nuclear Measurement Laboratory (LMN) of CEA Cadarache is involved in the development of time-correlated neutron detection techniques using plastic scintillators [1]. Until recently, 3 He proportional counters were commonly used for passive neutron coincidence counting owing to their high thermal neutron capture efficiency and gamma insensitivity.…”

Section: Introductionmentioning

confidence: 99%

Passive neutron coincidence counting with plastic scintillators for the characterization of radioactive waste drums

Deyglun¹,

Simony²,

Pérot³

et al. 2015

2015 4th International Conference on Advancements in Nuclear Instrumentation Measurement Methods and Their Applications (ANIMMA

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This paper reports a numerical feasibility study of a passive neutron coincidence counting system for radioactive waste drums with plastic scintillators. The motivation is to replace 3 He gas counters generally used for this type of measurement. Indeed, plastic scintillators present several advantages for the measurement of neutron coincidences such as a good efficiency for detecting fast neutrons, short detection time and low cost comparatively to 3 He. However, unlike 3 He counters, their high sensitivity to gamma rays and cross talk constitutes a drawback as parasite random and true coincidences are detected together with the useful signal of plutonium. Simulations are performed using the Monte Carlo transport code MCNPX-PoliMi v2.0 coupled to data processing algorithms developed with ROOT data analysis software. Performances of the coincidence counting system are studied for the case of a vitrified waste drum containing Pu and 241 Am, focusing particularly on coincidences with multiplicity 2 and 3. Cross talk induced by neutrons and gamma rays has been characterized in terms of time and distance between detectors, and strategies to limit this phenomenon are reported, consisting in paralyzing neighboring detectors. A significant improvement of the Pu to 241 Am ratio for multiplicity 3 coincidences has thus been obtained, to the detriment of counting statistics but making the measurement feasible.

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Non-classical applications of chemical analysis based on nuclear activation

Grdeń

2019

J Radioanal Nucl Chem

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Passive and Active Correlation Techniques for the Detection of Nuclear Materials

Cited by 10 publications

References 19 publications

Passive Neutron Coincidence Counting With Plastic Scintillators for the Characterization of Radioactive Waste Drums

Passive Neutron Coincidence Counting With Plastic Scintillators for the Characterization of Radioactive Waste Drums

Passive neutron coincidence counting with plastic scintillators for the characterization of radioactive waste drums

Non-classical applications of chemical analysis based on nuclear activation

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