Search results for: Maria Wallenius

Items from 1 to 20 out of 21 results

article

Certification of Uranium Isotope Amount Ratios in a Suite of Uranium Ore Concentrate Certified Reference Materials

Ruoxi Zhang, Kenny Nadeau, Eduardo Amilcar Gautier, Paola Alejandra Babay, more

Geostandards and Geoanalytical Research > 46 > 1 > 43 - 56

In this study, data from thirteen laboratories from around the world are presented for a successful certification of uranium isotope ratios in uranium ore concentrate (UOC) certified reference materials from the National Research Council Canada. Different mass spectrometric measurement principles (including SF‐ICP‐MS, quadruple ICP‐MS, TIMS, MC‐ICP‐MS, SIMS and AMS) and measurement procedures were...

article

Measurement of production date (age) of nanogram amount of uranium

Zsolt Varga, Maria Wallenius, Adrian Nicholl, Klaus Mayer, more

Journal of Radioanalytical and Nuclear Chemistry > 2019 > 322 > 3 > 1585-1591

JRC-Karlsruhe obtained a swipe sample from a highly enriched uranium seizure, which had taken place in 2011. Due to the very low amount of uranium (nanograms) a new method needed to be developed to determine the U production date (age). The particles on the swipe were collected on a pyrolytic graphite planchet using a vacuum impactor and they were subsequently leached with ccHNO₃. The “bulk” U isotopic...

article

Measurement of the ²³¹Pa/²³⁵U ratio for the age determination of uranium materials

Zsolt Varga, Adrian Nicholl, Erich Hrnecek, Maria Wallenius, more

Journal of Radioanalytical and Nuclear Chemistry > 2018 > 318 > 3 > 1565-1571

The paper describes the age (production date) determination of uranium reference materials using the ²³¹Pa/²³⁵U ratio. Direct addition of ²³⁷Np in secular equilibrium with its ²³³Pa daughter was chosen instead of the regular milking of ²³⁷Np to avoid possible loss of Pa. Sample preparation consists of a fast, one-step procedure. The developed method using ICP-MS for the measurement of ²³¹Pa is more...

article

The application of radiochronometry during the 4th collaborative materials exercise of the nuclear forensics international technical working group (ITWG)

Michael J. Kristo, Ross Williams, Amy M. Gaffney, Theresa M. Kayzar-Boggs, more

Journal of Radioanalytical and Nuclear Chemistry > 2018 > 315 > 2 > 425-434

In a recent international exercise, 10 international nuclear forensics laboratories successfully performed radiochronometry on three low enriched uranium oxide samples, providing 12 analytical results using three different parent-daughter pairs serving as independent chronometers. The vast majority of the results were consistent with one another and consistent with the known processing history of...

article

Uranium assay and trace element analysis of the fourth collaborative material exercise samples by the modified Davies-Gray method and the ICP-MS/OES techniques

Aubrey N. Nelwamondo, Lisa P. Colletti, Rachel E. Lindvall, Anna Vesterlund, more

Journal of Radioanalytical and Nuclear Chemistry > 2018 > 315 > 2 > 379-394

An international group of laboratories participating in CMX-4 subjected three samples to comparative nuclear forensic analysis using uranium assay and trace element analysis techniques to determine if the samples had similar or different origins. Uranium assay indicated that two pellet samples (ES-2 and ES-3) were nearly pure UO₂ while the black powder sample ES-1 was primarily UO₂ with UO₃ and/or...

article

Identification of uranium signatures relevant for nuclear safeguards and forensics

Zsolt Varga, Judit Krajkó, Maxim Peńkin, Márton Novák, more

Journal of Radioanalytical and Nuclear Chemistry > 2017 > 312 > 3 > 639-654

The paper describes the applicability of different characteristics (signatures) in nuclear safeguards and forensics for assessment of uranium material provenance in terms of production process. The study follows a uranium ore concentrate production from an ore to a U₃O₈ product. It turned out that rare-earth elemental pattern, radiochronometry (age of ore body and material production date), sulphur...

chapter

Analytical Chemistry of Plutonium*

Kenton J. Moody, Dawn A. Shaughnessy, Karin Casteleyn, Herbert Ottmar, more

The Chemistry of the Actinide and Transactinide Elements > 3889-4003

In 1940, shortly after the discovery of fission, McMillan and Abelson studied the recoil range of fission products induced by neutrons incident on a thin uranium foil (McMillan, 1939; McMillan and Abelson, 1940). While fission products were mostly ejected from the foil, two activities were significantly retained, one with a half-life of 23 min and the other with a half-life of 2.3 days.

article

Investigation of sulphur isotope variation due to different processes applied during uranium ore concentrate production

Judit Krajkó, Zsolt Varga, Maria Wallenius, Klaus Mayer, more

Journal of Radioanalytical and Nuclear Chemistry > 2016 > 309 > 3 > 1113-1121

The applicability and limitations of sulphur isotope ratio as a nuclear forensic signature have been studied. The typically applied leaching methods in uranium mining processes were simulated for five uranium ore samples and the n(³⁴S)/n(³²S) ratios were measured. The sulphur isotope ratio variation during uranium ore concentrate (UOC) production was also followed using two real-life sample sets obtained...

article

Plutonium age dating (production date measurement) by inductively coupled plasma mass spectrometry

Zsolt Varga, Adrian Nicholl, Maria Wallenius, Klaus Mayer

Journal of Radioanalytical and Nuclear Chemistry > 2016 > 307 > 3 > 1919-1926

This paper describes rapid methods for the determination of the production date (age dating) of plutonium (Pu) materials by inductively coupled plasma mass spectrometry (ICP-MS) for nuclear forensic and safeguards purposes. One of the presented methods is a rapid, direct measurement without chemical separation using ²³⁵U/²³⁹Pu and ²³⁶U/²⁴⁰Pu chronometers. The other method comprises a straightforward...

article

Titelbild: Uran aus deutschen Nuklearprojekten der 1940er Jahre – eine nuklearforensische Untersuchung (Angew. Chem. 45/2015)

Klaus Mayer, Maria Wallenius, Klaus Lützenkirchen, Joan Horta, more

Angewandte Chemie > 127 > 45 > 13331 - 13331

Nuklearforensik verfolgt die Spur zweier Uranblöcke zu den ersten deutschen Kernreaktionsexperimenten in den 1940er Jahren zurück. In der Zuschrift auf S. 13654 ff. vergleichen M. Wallenius et al. die makroskopischen Eigenschaften der Proben mit Literaturangaben, und sie bestimmen den Herstellungszeitpunkt und die Uranquelle.

article

Uran aus deutschen Nuklearprojekten der 1940er Jahre – eine nuklearforensische Untersuchung

Klaus Mayer, Maria Wallenius, Klaus Lützenkirchen, Joan Horta, more

Angewandte Chemie > 127 > 45 > 13654 - 13658

Wir berichten hier über eine nuklearforensische Analyse verschiedener Uranmaterialien aus deutschen Nuklearprojekten der 1940er Jahre, bei denen Uranmetall in verschiedenen Geometrien verwendet wurde. Mithilfe des ²³⁰Th/²³⁴U‐Isotopenverhältnisses konnte für das Metall ein Produktionszeitraum von 1940 bis 1943 bestimmt werden. Die geographische Herkunft des Urans wurde anhand des Spurengehalts an Seltenerdelementen...

article

Cover Picture: Uranium from German Nuclear Power Projects of the 1940s— A Nuclear Forensic Investigation (Angew. Chem. Int. Ed. 45/2015)

Klaus Mayer, Maria Wallenius, Klaus Lützenkirchen, Joan Horta, more

Angewandte Chemie International Edition > 54 > 45 > 13137 - 13137

Nuclear forensics was used to trace the history of two pieces of uranium metal, which are purported to originate from the first German nuclear reaction experiments in the 1940s. In their Communication on page 13452 ff., M. Wallenius et al. compared the macroscopic sample properties with literature information and determined the production date and source of the uranium samples.

article

Uranium from German Nuclear Power Projects of the 1940s— A Nuclear Forensic Investigation

Klaus Mayer, Maria Wallenius, Klaus Lützenkirchen, Joan Horta, more

Angewandte Chemie International Edition > 54 > 45 > 13452 - 13456

Here we present a nuclear forensic study of uranium from German nuclear projects which used different geometries of metallic uranium fuel.3b,d, 4 Through measurement of the ²³⁰Th/²³⁴U ratio, we could determine that the material had been produced in the period from 1940 to 1943. To determine the geographical origin of the uranium, the rare‐earth‐element content and the ⁸⁷Sr/⁸⁶Sr ratio were measured...

article

Application of neodymium isotope ratio measurements for the origin assessment of uranium ore concentrates

Judit Krajkó, Zsolt Varga, Ezgi Yalcintas, Maria Wallenius, more

Talanta > 2014 > 129 > Complete > 499-504

A novel procedure has been developed for the measurement of ¹⁴³ Nd/ ¹⁴⁴ Nd isotope ratio in various uranium-bearing materials, such as uranium ores and ore concentrates (UOC) in order to evaluate the usefulness and applicability of variations of ¹⁴³ Nd/ ¹⁴⁴ Nd isotope ratio for provenance assessment in nuclear forensics.Neodymium was separated and pre-concentrated by...

article

Attribution of uranium ore concentrates using elemental and anionic data

Elizabeth Keegan, Maria Wallenius, Klaus Mayer, Zsolt Varga, more

Applied Geochemistry > 2012 > 27 > 8 > 1600-1609

The capability to correctly identify the geological or geographical source of unknown uranium ore concentrates (UOCs) has obvious nuclear security benefits. This paper reports on a scoping study where the trace elemental and anionic compositions of 24 UOC samples, sourced mainly from mines in Australia and Canada, were examined for their ability to allow attribution of the sample to a particular geological...

article

Development and validation of a methodology for uranium radiochronometry reference material preparation

Zsolt Varga, Adrian Nicholl, Maria Wallenius, Klaus Mayer

Analytica Chimica Acta > 2012 > 718 > Complete > 25-31

The paper describes a methodology for a reference material preparation to be used for the determination of the production date (i.e. the time elapsed since the last chemical processing) of uranium materials based on the ²³⁰ Th/ ²³⁴ U radiochronometer. The reference material was prepared from highly enriched uranium by a complete separation of thorium decay products, thus zeroing the...

article

Alternative method for the production date determination of impure uranium ore concentrate samples

Zsolt Varga, Maria Wallenius, Klaus Mayer, Erich Hrnecek

Journal of Radioanalytical and Nuclear Chemistry > 2011 > 290 > 2 > 485-492

A novel method has been developed for the determination of the production date (age) of uranium ore concentrates (yellow cakes). The methodology is based on the measurement of trace-level ²³²Th and its daughter nuclide, ²²⁸Th and their variation over time. The proposed method offers a complementary dating tool to the commonly used ²³⁰Th/²³⁴U technique, which is applicable, however, only for highly...

article

Determination of rare-earth elements in uranium-bearing materials by inductively coupled plasma mass spectrometry

Zsolt Varga, Róbert Katona, Zsolt Stefánka, Maria Wallenius, more

Talanta > 2010 > 80 > 5 > 1744-1749

A novel and simple analytical procedure has been developed for the trace-level determination of lanthanides (rare-earth elements) in uranium-bearing materials by inductively coupled plasma sector-field mass spectrometry (ICP-SFMS). The method involves a selective extraction chromatographic separation of lanthanides using TRU™ resin followed by ICP-SFMS analysis. The limits of detection of the method...

article

Application of Lead and Strontium Isotope Ratio Measurements for the Origin Assessment of Uranium Ore Concentrates

Zsolt Varga, Maria Wallenius, Klaus Mayer, Elizabeth Keegan, more

Analytical Chemistry > 2009 > 81 > 20 > 8327 - 8334

article

Nuclear forensic investigations with a focus on plutonium

Maria Wallenius, Klaus Lützenkirchen, Klaus Mayer, Ian Ray, more

Journal of Alloys and Compounds > 2007 > 444-445 > Complete > 57-62

Since the beginning of the 1990s when the first seizures of nuclear material were reported, the IAEA has recorded over 200 cases of illicit trafficking of nuclear materials. Despite the decreasing frequency of nuclear material seizures, particularly the ones involving weapons-grade material, the issue continues to attract public attention and is a reason for concern due to the hazard associated with...

Publication date

Last 3 years (1)

Close

Date range setting

Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.

From:

To:
Set your own date range

INFONA - science communication portal

Search results for: Maria Wallenius

Certification of Uranium Isotope Amount Ratios in a Suite of Uranium Ore Concentrate Certified Reference Materials

Measurement of production date (age) of nanogram amount of uranium

Measurement of the ²³¹Pa/²³⁵U ratio for the age determination of uranium materials

The application of radiochronometry during the 4th collaborative materials exercise of the nuclear forensics international technical working group (ITWG)

Uranium assay and trace element analysis of the fourth collaborative material exercise samples by the modified Davies-Gray method and the ICP-MS/OES techniques

Identification of uranium signatures relevant for nuclear safeguards and forensics

Analytical Chemistry of Plutonium*

Investigation of sulphur isotope variation due to different processes applied during uranium ore concentrate production

Plutonium age dating (production date measurement) by inductively coupled plasma mass spectrometry

Titelbild: Uran aus deutschen Nuklearprojekten der 1940er Jahre – eine nuklearforensische Untersuchung (Angew. Chem. 45/2015)

Uran aus deutschen Nuklearprojekten der 1940er Jahre – eine nuklearforensische Untersuchung

Cover Picture: Uranium from German Nuclear Power Projects of the 1940s— A Nuclear Forensic Investigation (Angew. Chem. Int. Ed. 45/2015)

Uranium from German Nuclear Power Projects of the 1940s— A Nuclear Forensic Investigation

Application of neodymium isotope ratio measurements for the origin assessment of uranium ore concentrates

Attribution of uranium ore concentrates using elemental and anionic data

Development and validation of a methodology for uranium radiochronometry reference material preparation

Alternative method for the production date determination of impure uranium ore concentrate samples

Determination of rare-earth elements in uranium-bearing materials by inductively coupled plasma mass spectrometry

Application of Lead and Strontium Isotope Ratio Measurements for the Origin Assessment of Uranium Ore Concentrates

Nuclear forensic investigations with a focus on plutonium

Filter options

Publication date

Publication type

Publication language

Keywords

Data set

Journal

INFONA - science communication portal

Search results for: Maria Wallenius

Add recipient

Sending message cancelled

Are you sure you want to cancel sending this message?

Send message

Filter options

Publication date

Date range setting

Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.

Publication type

Publication language

Keywords

Data set

Journal

Reporting an error / abuse

Sending the report failed

Accessibility options