Results of the REIMEP-17 and NUSIMEP-8 inter-laboratory comparisons

Confidence in measurement results is established via reference materials, reference measurements and inter-laboratory comparisons. The Institute for Reference Materials and Measurements of the Joint Research Centre of the European Commission (EC-JRC-IRMM) has a long time experience in the development of nuclear isotopic reference materials and in the organisation of inter-laboratory comparisons (ILCs) in compliance with the respective international ISO guides. The Regular European Inter-laboratory measurement Evaluation Programme (REIMEP) was established at IRMM in 1982 for carrying out external quality control of the measurements for the elements characteristic of the nuclear fuel cycle, while the Nuclear Signatures Inter-laboratory Measurement Evaluation Programme (NUSIMEP) aims to provide test samples for the measurement of trace amounts of nuclear material in environmental matrices. Participants in REIMEP/NUSIMEP can benchmark their measurement results against independent and traceable reference values, assessing their measurement capabilities in line with international or national quality goals. The REIMEP-17 and NUSIMEP-8 certified test samples were prepared from dissolution of mixed oxide fuel in nitric acid and addition of natural uranium. In REIMEP-17 laboratories received two test samples with undisclosed values of the U, Pu amount content and U and Pu isotope amount ratios. The certified test sample REIMEP-17A had a concentration typical for undiluted input solution whereas REIMEP 17B was a diluted fraction thereof. The NUSIMEP-8 certified test sample was prepared by further gravimetrical dilution of REIMEP-17B. Measurement of the n(235U)/n(238U) and n(240Pu)/n(239Pu) ratios were obligatory while the measurement of other ratios were optional. Laboratories were asked to apply their routine analytical procedures and report the results with associated measurement uncertainty. The participant results have been evaluated against the independent certified reference value by means of z and zeta scores in compliance with ISO 13528:2005. In general, the REIMEP-17 results were satisfactory and in compliance with the International Target Values for Measurement Uncertainties in Safeguarding Nuclear Materials (ITV2010). The NUSIMEP-8 results were overall satisfactory and met the International Atomic Energy Agency Measurement Quality Goals (IAEA-SGAS-QC) for the analysis of bulk environmental samples.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

REIMEP-17: Plutonium and uranium amount content, and isotope amount ratios in synthetic input solution - Inter-laboratory comparison, Report to participants

Nuclear safeguards is based on international agreements and in the EU has the rank of European law (Euratom Treaty, Chapter VII, Euratom regulation 302/2005) ensuring that materials usable in both peaceful and military applications – such as uranium and plutonium – are used for peaceful purposes only. Physical verification measurements at nuclear facilities, such as reprocessing and fuel fabrication plants, are a part of safeguards inspections. The reliability of measurement results in nuclear material accountancy and verification is indispensable for an effective safeguards system. A new external quality control campaign, REIMEP-17 on "Plutonium and uranium amount content, and isotope amount ratios in synthetic input solution" was organised by JRC-IRMM in cooperation with JRC-ITU, particularly for EURATOM safeguards (DG ENER) laboratories and the IAEA Network of Analytical Laboratories for nuclear material analysis (IAEA-NWAL), as well as for laboratories from industry and experts in the field. Participating laboratories in REIMEP-17 received two samples with undisclosed U, Pu amount content and n(238Pu)/n(239Pu), n(240Pu)/n(239Pu), n(241Pu)/n(239Pu) n(242Pu)/n(239Pu) and n(234U)/n(238U), n(235U)/n(238U), n(236U)/n(238U) amount ratio values. One of the samples, REIMEP 17A had uranium and plutonium amount contents typical for undiluted spent nuclear fuel input solution and the other sample, REIMEP-17B was a diluted fraction of it. The participants were requested to apply their standard analytical procedures and report the results with the associated uncertainties. The laboratories were also requested to complete and return a questionnaire so that an overall picture of the laboratories’ capabilities could be made. REIMEP-17 was announced to participants in April 2012. Sixteen laboratories registered for REIMEP 17. Due to delays in the shipment of the samples and problems with the transport containers, three laboratories were not able to receive the samples. Three laboratories withdrew their participation. Consequently, the deadline for submitting the results had to be extended until July 1, 2013. In the end JRC-IRMM received results from nine laboratories; one laboratory did not submit the results. The reported measurement results have been evaluated against the independent reference values by means of z-scores and zeta-scores in compliance with international guidelines. In general the REIMEP-17 participants' results were satisfactory and in compliance with the International Target Values for Measurement Uncertainties in Safeguarding Nuclear Materials (ITV2010). This report presents the REIMEP-17 participants' results; including the evaluation of the questionnaire.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

NUSIMEP-8: Uranium and plutonium isotope amount ratios in low-level synthetic nitrate solution - Inter-laboratory comparison, Report to participants

The Additional Protocol (AP) authorizes safeguards authorities to verify the absence of undeclared nuclear activities in all parts of a state’s nuclear fuel cycle as well as any other location where nuclear material is or may be present. As a part of the Additional Protocol, environmental sampling has become an important tool for the detection of non-declared nuclear activities. In environmental sampling, swipe samples are collected for bulk and particle analysis. Considering the potential consequences of the analyses, these measurements need to be subjected to a rigorous quality management system. The Nuclear Signatures Inter-laboratory Measurement Evaluation Programme (NUSIMEP) was established in 1996 to support the growing need to trace and measure the isotopic abundances of elements characteristic for the nuclear fuel cycle present in trace amounts in the environment. NUSIMEP-8 focused on measurements of low-level uranium and plutonium in synthetic nitrate solution aiming to support EURATOM safeguards (DG ENER), the IAEA Network of Analytical Laboratories (NWAL) for bulk analysis of environmental samples and laboratories in the field. The NUSIMEP-8 solution was prepared from mixed oxide fuel dissolved in nitric acid with addition of natural uranium and diluted to an environmental level. Participating laboratories in NUSIMEP-8 received one sample solution with undisclosed values of n(238Pu)/n(239Pu), n(240Pu)/n(239Pu), n(241Pu)/n(239Pu), n(242Pu)/n(239Pu) and n(234U)/n(238U), n(235U)/n(238U), n(236U)/n(238U) amount ratios. Those isotope amount ratios were measured by participating laboratories using their routine analytical procedures. Measurement of the major isotope ratios n(235U)/n(238U) and n(240Pu)/n(239Pu) were obligatory; measurement of the minor isotope ratios were optional. 25 laboratories registered for NUSIMEP-8, three withdrew the registration while one laboratory encountered problems with the shipment of the sample. Finally, 19 participants have reported measurement results using different analytical techniques, among those 10 NWAL laboratories. Two participants did not report their results due to technical problems. The participant measurement results have been evaluated against the certified reference values by means of z-scores and zeta-scores in compliance with ISO 13528:2005. The NUSIMEP-8 results were overall satisfactory and in compliance with the IAEA Measurement Quality Goals for the analysis of bulk environmental samples. This report presents the NUSIMEP-8 participant results; including the evaluation of the questionnaire. In addition feedback from the measurement communities in nuclear safeguards, nuclear security and environmental sciences was collected in view of identifying future needs for NUSIMEP inter-laboratory comparisons.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

Results of the REIMEP-17 interlaboratory comparison for the measurement of the U and Pu amount content and isotope amount ratios in the synthetic dissolved spent nuclear fuel solution

Reliable measurements are needed for the verification measures of States’ declarations of their nuclear activities in line with international agreements and the EURATOM Treaty. Laboratories carrying out measurements of nuclear material need to follow stringent quality control concepts and are required to demonstrate their measurement capabilities on a regular and timely basis to legal and Safeguards authorities. This includes participation in interlaboratory comparisons (ILCs). In the frame of the Regular European Interlaboratory Measurement Evaluation Programme (REIMEP) a new ILC (REIMEP-17) was jointly organized by the EC-Joint Research Centre-Institute for Reference Materials and Measurements (JRC-IRMM) and EC-Joint Research Centre-Institute for Transuranium Elements (JRC-ITU) for EURATOM and IAEA safeguards laboratories, nuclear plant operators and nuclear material laboratories. The focus in REIMEP-17 was on measurements of the uranium and plutonium amount contents, and isotope amount ratios in synthetic input solutions. Participants received two test samples, REIMEP-17A and REIMEP 17B, with different uranium and plutonium amount contents. Laboratories were requested to report the results with associated uncertainties applying their standard measurement procedures, and had the possibility to benchmark those results against the independent assigned (reference) values and the International Target Values for Measurement Uncertainties in Safeguarding Nuclear Materials (ITV2010). It can be concluded that the participants in REIMEP-17 performed well for the measurements of uranium and plutonium amount content in compliance with the respective ITV2010. In particular, the measurement performance for the isotope amount ratios was very satisfactory for both REIMEP-17 test samples. This confirms the measurement capabilities of laboratories in the field of nuclear material analysis and demonstrates that the stringent ITV2010 are achievable target values under state-of-practice conditions. On the other hand, the spread of results for the minor uranium isotope amount ratios was larger. Moreover, for some of the measurands, differences in the measurement uncertainty estimations provided by laboratories were observed even when using the same instrumental technique. A summary of the participant results is presented and discussed in this paper.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

Isotopen- und Spurenelementuntersuchungen von geologischen Systemen

Thermal Ionization Mass Spectrometry (TIMS) and Synchrotron X-Ray Fluoresence (SYXRF) are two methods for analyzing the isotope and trace element compositions of geological materials (e.g. rocks and fluids), in order to reconstruct their origin and history. We present several examples of how geological problems can be solved using these analytical methods: 1) age-dating of the oceanic crust beneath Gran Canaria (Canary Islands) using the Sm-Nd isotopic system, 2) tracing the origin of volcanic seamounts, ridges and ophiolites along the Pacific margin of Costa Rica with radiogenic isotope systems (Sr, Nd and Pb), 3) evaluating the role of seawater alteration on the composition of the oceanic crust using B isotopes, and 4) determining the input of halogens and other elements into the stratosphere during volcanic eruptions and assessing their effect on the ozone layer

Synthesis and characterization of homogeneous (U,Am)O₂ and (U,Pu,Am)O₂ nanopowders

This paper details the first dedicated production of homogeneous nanocrystalline particles of mixed actinide oxide solid solutions containing americium. The target compositions were $U_{0.75}Pu_{0.20}Am_{0.05}O_{2}$, $U_{0.90}Am_{0.10}O_{2}$ and $U_{0.80}Am_{0.20}O_{2}$. After successful hydrothermal synthesis and chemical characterisation, the nanocrystals were sintered and their structure and behaviour under self-irradiation were studied by powder XRD. Cationic charge distribution of the as-prepared nanocrystalline and sintered $U_{0.80}Am_{0.20}O_{2}$ materials was investigated applying $U M_{4}$ and $Am M_{5}$ edge high energy resolution XANES (HR-XANES). Typical oxidation states detected for the cations are $U_{(IV)}/U_{(V)}$ and $Am_{(III)}/Am_{(IV)}$. The measured crystallographic swelling was systematically smaller for the as-synthesised nanoparticles than the sintered products. For sintered pellets, the maximal volumetric swelling was about 0.8% at saturation, in line with literature data for $PuO_{2}$, $AmO_{2}$, $(U,Pu)O_{2}$ or $(U,Am)O_{2}$

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