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Since 1987, the CEA’s Committee for the establishment of analysis methods (CETAMA) has regularly implemented interlaboratory comparisons, entitled “evaluation of the quality results of analysis in the nuclear industry” (EQRAIN). Notably, the EQRAIN U and EQRAIN Pu interlaboratory comparisons assess proficiency in measuring a mass content of uranium or plutonium in reference solutions. This paper presents the results of measurement uncertainty assessments from EQRAIN U and EQRAIN Pu comparisons over 20 years of exercises (1997–2016). The mathematical approach developed in this work allowed to estimate the impact of short-term systematic and random errors to the overall uncertainty of each analytical method used in the interlaboratory comparison program. This statistical analysis shows a good consistency between measurement uncertainty values from EQRAINs and the measurement uncertainty target values established by the International Atomic Energy Agency for nuclear material balances (ITVs-2010).

In the original publication of the article, the values of u(s), u(r) and ITV for HKED were published incorrectly in Table 6.

To meet a need expressed by the French nuclear laboratories, the Commission for the Establishment of Analytical Methods (CETAMA) has provided a new reference material with high level in plutonium isotope 242 Pu and certified in isotopic ratio. Based on the ISO guide 34, the production of this material by LAMMAN laboratory (Metrology Laboratory of Nuclear Material) in CEA Marcoule has been made from a solution of plutonium nitrate enriched in 242 Pu. The certification process has been undertaken by interlaboratory comparison in collaboration with five French and European laboratories. The method of mass spectrometry thermal ionization (TIMS) was recommended as the analytical technique for certification. The statistical processing of the data provided by the laboratories has been done by four different approaches. The “excess-variance” approach has proved to be the best to process these data. After determining certified values and their associated uncertainties, a certificate has been established for this new reference material 242 Pu.