The Euratom Safeguards On-site Laboratories at the Reprocessing Plants of La Hague and Sellafield

In the European Union, nuclear material is reprocessed from irradiated power reactor fuel at two sites ¿ La Hague in France and Sellafield in the United Kingdom. These are the largest nuclear sites within the EU, processing many hundreds of tons of nuclear material in a year. Under the Euratom Treaty, the European Commission has the duty to assure that the nuclear material is only used for declared purposes. The Directorate General for Energy (DG ENER), acting for the Commission, assures itself that the terms of Article 77 of Chapter VII of the Treaty have been complied with. In contrast to the Non Proliferation Treaty, the Euratom Treaty requires to safeguard all civil nuclear material in all EU member states ¿ including the nuclear weapons states. The considerable amount of fissile material separated per year (several tonnes) calls for a stringent system of safeguards measures. The aim of safeguards is to deter diversion of nuclear material from peaceful use by maximizing the chance of early detection. At a broader level, it provides assurance to the public that the European nuclear industry, the EU member states and the European Union honour their legal duties under the Euratom Treaty and their commitments to the Non-Proliferation Treaty. Efficient and effective safeguards measures are essential for the public acceptance of nuclear activities.JRC.E.7-Nuclear Safeguards and Forensic

Experiences in Uranium Abundance Analysis Using the MTE Methodology

The ITU in Karlsruhe routinely analyses a multitude of samples from a wide range of internal and external customers for safeguards. High through-put analysis techniques are employed using meticulous care to ensure accurate, precise and timely results are provided. Thermal ionisation mass spectrometry (TIMS) is used for isotopic analysis of Uranium to determine abundance and concentration information. At ITU we employ the modified total evaporation (MTE) methodology[1] for minor isotope analysis of the U234 and U236 isotopes and have observed varying run quality between different samples. As a consequence an investigation was instigated to identify possible causes for the run differences and find a general solution for a more consistent analysis approach. The investigation was focused around the form of Uranium (nitrate, carbonate, etc. ), and after individual chemical processing, how the sample dried on the filament for analysis. The visual appearance of the samples varied significantly. Comparison of the observations with data from the analysis run indicated that impurities within the sample matrices were causing run differences due to the large amount of sample required, 5 µg, for the MTE analysis.JRC.E.7-Nuclear Safeguards and Forensic

Improvements in Routine Uranium Isotope Ratio Measurements Using the Modified Total Evaporation Method for Multi-Collector Thermal Ionization Mass Spectrometry

A new version of the "modified total evaporation" (MTE) method for isotopic analysis of uranium samples by multi-collector thermal ionization mass spectrometry (TIMS), with high analytical performance and designed in a more user-friendly and routinely applicable way, is described in detail. It is mainly being used for nuclear safeguards measurements, but can readily be applied in other scientific areas like geochemistry. The development of the MTE method was organized in collaboration of several "key nuclear mass spectrometry laboratories", namely the New Brunswick Laboratory (NBL), the Safeguards Analytical Laboratory (SAL, now SGAS=Safeguards Analytical Services) of the International Atomic Energy Agency (IAEA), the Institute for Transuranium Elements (ITU/JRC), and the Institute for Reference Materials and Measurements (IRMM/JRC), with IRMM taking the leading role. Due to the use of the "total evaporation" (TE) principle the measurement of the "major" ratio n(235U)/n(238U) is routinely being performed with an accuracy of 0.02%. In contrast to the TE method, in the MTE method the total evaporation process is interrupted on a regular basis to allow for correction for background from peak tailing, internal calibration of a secondary electron multiplier (SEM) detector versus the Faraday cups, peak-centering, and ion source re-focusing. Therefore, the most significant improvement using the MTE method is in the measurement performance achieved for the "minor" ratios n(234U)/n(238U) and n(236U)/n(238U). The n(234U)/n(238U) ratio is measured using Faraday cups only with the result that the "measurement performance", defined here as the sum of the (relative) deviation of the measured from the true (certified) value plus the (relative) measurement uncertainty (k = 2), is better than 0.12%. Furthermore, the IAEA requirement for the measurement performance for n(236U)/n(238U) ratio measurements is 1x10-6, but the MTE method provides a measurement performance which is, depending on the ratio, by several orders of magnitude superior compared to that. For routine MTE measurements a detection limit of 3x10-9 was achieved using an SEM detector for detecting the isotope 236U. The MTE method is now routinely being used at all collaborating laboratories with the hope that more laboratories will implement this capability in the future as well. Additional applications for the MTE method are presented in this paper, e.g., for absolute Ca isotope measurements.JRC.DG.D.2-Reference material

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

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. The results provide evidence that the uranium was mined in the Czech Republic. Trace amounts of 236U and 239Pu were detected at the level of their natural abundance, which indicates that the uranium fuel was not exposed to any major neutron fluence.JRC.E.7-Nuclear Safeguards and Forensic

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

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 und der Strontium-Isotopenverhältnisse bestimmt. Die Ergebnisse zeigen, dass das bei den deutschen Nuklearprojekten verwendete Uran aus Minen in der Tschechischen Republik stammt. 236U und 239Pu wurden in Spuren nachgewiesen. Diese entsprechen in etwa der Häufigkeit dieser Isotope in Uranerzen, woraus sich ableiten lässt, dass die untersuchten Uranmetalle keinem signifikanten Neutronenfluss ausgesetzt waren.JRC.E.7-Nuclear Safeguards and Forensic

The Safeguards On-Site Laboratory at La Hague June 2000 - June 2005 - Experience over Five Years of Operation

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Comparative assessment of the Pu content of MOX samples by different techniques

The isotopic composition and concentration of Pu in eight "high-burn-up" mixed-oxide (MOX) fuel samples has been determined by destructive and non-destructive techniques. In addition, the U concentration and U isotopic composition was also available from the destructive techniques. The applied non-destructive techniques were gamma spectrometry, calorimetry and neutron coincidence counting, while the destructive techniques were titration, alpha spectrometry and thermal ionization mass spectrometry combined with isotope dilution. The current study describes the measurements and compares the results obtained by the mentioned techniques. Some lessons learned for the improvement of the non-destructive assay are also discussed.JRC.E.7-Nuclear Safeguards and Forensic

In-field Timely and Accurate Measurements - Fundamental to Minimising Safeguards Issues in Reprocessing Facilities

The two large reprocessing plants in Europe, located in Sellafield (UK) and La Hague (F) have a throughput of 800 t and 1600 t of spent fuel per year. In order to meet the safeguards criteria of quantity, timeliness and probability (QTP), these facilities deserve particular attention and appropriate safeguards measures have to be implemented. At either plant Euratom installed an on-site laboratory where the verification measurements are performed with minimal time delays and at highest possible accuracy.JRC.E-Institute for Transuranium Elements (Karlsruhe