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

Abstract

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 dissolved spent nuclear fuel 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 ones listed in 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 values. 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 values are achievable targets 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.

30 years of IRMM-1027 reference materials for fissile material accountancy and control: development, production and characterisation

“…About 1000 units of IRMM-1027 LSD spikes are produced annually and certified in compliance with the ISO 17034 and ISO Guide 35 [14,15]. Spikes containing 235 U and 239 Pu have been successfully utilised in IDMS for safeguards inspections and in accountability measurements for operators at the reprocessing plants [9,10,[16][17][18][19][20]. The extensive use of LSD spikes over the past years has shown that IDMS, applying these spikes routinely, provides accurate results with measurement uncertainties below the target values as required by the safeguards authorities.…”

Long-term stability of cellulose acetate butyrate thin films for nuclear certified reference materials

“…The measurements are carried out with Isotope Dilution Thermal Ionization Mass Spectrometry (ID-TIMS) by plant operators and safeguards authorities by the European Commission and also outside EU [5]. The uncertainty that is introduced by this reference material is very low, and allows the laboratories to achieve IDMS measurements results with uncertainties below the target value of 0.28 % for hot-cell conditions, expressed as a relative standard uncertainty [6, 7]. …”