Nucleogenic 36Cl, 236U and 239Pu in uranium ores

Wilcken, Klaus M.; Fifield, L.K.; Barrows, Timothy T.; Tims, S.G.; Gladkis, Laura G.

doi:10.1016/j.nimb.2008.06.009

Cited by 49 publications

(34 citation statements)

References 23 publications

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“…Moreover, the measured n( 236 U)/ n( 238 U) are in the order of magnitude of uranium ores, which is reported to range between 10 -12 and 3·10 -10 [5]. More specifically, for uranium from the Joachimsthal mine (sampled prior to atmospheric nuclear weapons tests), a n( 236 U)/ n( 238 U) ratio of (7.0 ± 0.5) · 10 -11 was measured, while earlier work reported a slightly lower value of (5.8 ± 0.5) · 10 -11 [5]. Thus, the uranium isotopic composition did not provide solid evidence of an exposure of the uranium to significant neutron fluence.…”

Section: Figure 4 Neutron Reactions and Subsequent Radioactive Decay mentioning

confidence: 94%

“…Further investigations were carried out using the 14UD Pelletron tandem accelerator in the Department of Nuclear Physics at the Australian National University. The methodology is described in more detail in [ 5 ]. The results of the measurements do not suggest a significant difference between the three samples.…”

Section: Figure 4 Neutron Reactions and Subsequent Radioactive Decay mentioning

confidence: 99%

See 1 more Smart Citation

Nuclear Forensics: A Methodology Applicable to Nuclear Security and to Non-Proliferation

Mayer¹,

Wallenius²,

Lützenkirchen³

et al. 2011

J. Phys.: Conf. Ser.

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Nuclear Security aims at the prevention and detection of and response to, theft, sabotage, unauthorized access, illegal transfer or other malicious acts involving nuclear material". Nuclear Forensics is a key element of nuclear security. Nuclear Forensics is defined as a methodology that aims at re-establishing the history of nuclear material of unknown origin. It is based on indicators that arise from known relationships between material characteristics and process history. Thus, nuclear forensics analysis includes the characterization of the material and correlation with production history.To this end, we can make use of parameters such as the isotopic composition of the nuclear material and accompanying elements, chemical impurities, macroscopic appearance and microstructure of the material. In the present paper, we discuss the opportunities for attribution of nuclear material offered by nuclear forensics as well as its limitations. Particular attention will be given to the role of nuclear reactions. Such reactions include the radioactive decay of the nuclear material, but also reactions with neutrons. When uranium (of natural composition) is exposed to neutrons, plutonium is formed, as well as 236 U. We will illustrate the methodology using the example of a piece of uranium metal that dates back to the German nuclear program in the 1940's. A combination of different analytical techniques and model calculations enables a nuclear forensics interpretation, thus correlating the material characteristics with the production history.

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Section: Figure 4 Neutron Reactions and Subsequent Radioactive Decay mentioning

confidence: 94%

Section: Figure 4 Neutron Reactions and Subsequent Radioactive Decay mentioning

confidence: 99%

Nuclear Forensics: A Methodology Applicable to Nuclear Security and to Non-Proliferation

Mayer¹,

Wallenius²,

Lützenkirchen³

et al. 2011

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

show abstract

“…Regarding the abundance sensitivity results, the ANU is the best system in the word together with VERA laboratory (Steier et al, 2010). The ANU is able to obtain values of 236 U/ 238 U≃10 −13 (Wilcken et al, 2008), in samples including about 1 mg of U. This results is obtained with a time of flight of 2.3 m. Preliminary results have been obtained with a 6 m flight path; the longer flight path confers a substantial improvement in the ability to separate 235 U and 236 U with little reduction in efficiency .…”

Section: Detection Systems and Anu Actinide Resultsmentioning

confidence: 97%

“…For plutonium measurements no interfering ions exist; an ionization chamber is suitable for such a detection. The ANU configuration of the ionization chamber (Fifield et al, 1996;Wilcken, 2006;Wilcken et al, 2008) are the following; ∼ 50 torr of propane is used as the detector gas and the window is a 0.7 µm thick Mylar foil. Applied voltages are: cathode ≃ -600 V, detector window ≃ -300 V, first grid at ground, second grid at ≃ +200 V and anode ≃ +600 V. The energy of the 239 Pu 5+ ions is ∼ 24.5 MeV.…”

Section: Detection Systems and Anu Actinide Resultsmentioning

confidence: 99%

Origin and Detection of Actinides: Where Do We Stand with the Accelerator Mass Spectrometry Technique?

Cesare¹

2011

Nuclear Power - Control, Reliability and Human Factors

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“…Furthermore, extraction and measurement of 236 U and the Pu isotopes from the same environmental material has been demonstrated at the levels necessary [12,13]. There is, however, very little data in the literature regarding concentrations of fallout 236 U in soils, and even less regarding the use of 236 U as an environmental tracer, although first attempts have been reported recently [14,15].…”

Section: Uranium-236mentioning

confidence: 99%

Actinides, accelerators and erosion

Tims

Fifield

2012

EPJ Web of Conferences

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Abstract. Fallout isotopes can be used as artificial tracers of soil erosion and sediment accumulation. The most commonly used isotope to date has been 137 Cs. Concentrations of 137 Cs are, however, significantly lower in the Southern Hemisphere, and furthermore have now declined to 35% of original values due to radioactive decay. As a consequence the future utility of 137 Cs is limited in Australia, with many erosion applications becoming untenable within the next 20 years, and there is a need to replace it with another tracer. Plutonium could fill this role, and has the advantages that there were six times as many atoms of Pu as of 137 Cs in fallout, and any loss to decay has been negligible due to the long half-lives of the plutonium isotopes. Uranium-236 is another long-lived fallout isotope with significant potential for exploitation as a tracer of soil and sediment movement. Uranium is expected to be more mobile in soils than plutonium (or caesium), and hence the 236 U/Pu ratio will vary with soil depth, and so could provide an independent measure of the amount of soil loss. In this paper we discuss accelerator based ultra-sensitive measurements of plutonium and 236 U isotopes and their advantages over 137 Cs as tracers of soil erosion and sediment movement.

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Nucleogenic 36Cl, 236U and 239Pu in uranium ores

Cited by 49 publications

References 23 publications

Nuclear Forensics: A Methodology Applicable to Nuclear Security and to Non-Proliferation

Nuclear Forensics: A Methodology Applicable to Nuclear Security and to Non-Proliferation

Origin and Detection of Actinides: Where Do We Stand with the Accelerator Mass Spectrometry Technique?

Actinides, accelerators and erosion

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