Characterisation of activity content of 226Ra in spiked metallurgical slag using an interlaboratory comparison

More than half of yearly steel production in EU comes from recycling. The metal foundries pass the metal scrap through radiation portal monitors at the entrance of the foundry; nevertheless an orphan radioactive source may still remain undetected e.g. due to the shielding from the scrap load itself. In such case the source may enter the smelting route ending in contaminated steel products and by-products of the process. The European metal foundries are aware of the problem and increasingly apply radioactivity monitoring of the steel products. It is of outmost importance to perform accurate measurements, in order to prove compliance with respect to legal radioactivity limits, and metrologically challenging to ensure the quality of such measurements. In the light of a global steel market it is obvious that harmonisation of the analytical methodologies is critical. In the EURAMET's EMRP joint research project, 'MetroMetal' (Ionising radiation metrology for the metallurgical industry), existing radioactivity measurement methods were studied and new optimized methods, systems and standards were proposed for the radioactivity control of steel and by-products in steel mills. In this context, reference activity standards, including the most frequently occurring radionuclides in melting incidents in suitable geometries and matrices, have been developed. Amongst these standards were two series of sources of 60Co in cast steel, one of 137Cs in fume dust and one of 226Ra in furnace slag. The common feature in all four standards was that Interlaboratory comparisons (ILCs) were used to characterise the activity concentrations. In the particular case of 226Ra in slag the material was prepared by spiking and an ILC was conducted amongst 9 European National Metrology Laboratories and JRC, with the aim to verify the activity concentration of the spiked material and to validate the calibration and correction methods proposed by MetroMetal. In the present work, the organization and the results of the ILC on 226Ra activity concentration in metallurgical slag standards are presented.JRC.G.2-Standards for Nuclear Safety, Security and Safeguar

International comparison of activity measurements of radon 222: EURAMET Project n°1475 – EURAMET.RI(II)-S8.Rn-222

International audienceAn international comparison of activity per unit volume of 222Rn (EURAMET project N° 1475, registered in KCDB as supplementary comparison EURAMET.RI(II)-S8.Rn-222) was organised in 2019 within the framework of the European project MetroRADON. The LNE-LNHB is the pilot of the comparison. Samples of 222Rn gas provided by the LNE-LNHB were sent to the participants and were measured using various techniques. The reference value is the power moderated mean (PMM) (Pommé, 2013) of the seven submitted results

International Exercise on 124Sb Photon Emission Intensities Determination

An international exercise, registered as EUROMET project n° 907, was launched to measure both the activity of a solution of 124Sb and the photon emission intensities of its decay. The same solution was sent by LNE-LNHB to eight participating laboratories. Activity measurements were performed using the 4 pi beta-gamma coincidence counting technique, CIEMAT/NIST liquid scintillation counting, a well-type ionization chamber and a well-type crystal detector. The results are compared and possible explanations for discrepancies are sought. Six participants sent results for photon emission intensities both in absolute and in relative values. From these results and including previous published values a consistent decay scheme was worked out, proving that problems in activity measurements are not due to decay scheme data.JRC.D.4-Nuclear physic

Results of an international comparison for the activity measurement of 177Lu

An international Key Comparison of 177Lu has recently been carried out. A total of twelve laboratories performed assays for radioactivity content on aliquots of a common master solution of 177Lu, leading to eleven results submitted for entry into the Key Comparison Database or the Mutual Recognition Arrangement. A proposed Comparison Reference Value (CRV) was calculated to be 3.288(5) MBq·g-1 using all eleven results. Degrees of equivalence (DOE) and their associated uncertainties were calculated for each reporting laboratory based on the CRV. Most of the values reported by the participating laboratories were within 0.6 % of the CRV.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

Supplementary comparison of the measurement of the alpha and beta particle surface emission rates from large area sources (CCRI(II)-S10 LASCE)

International audienceIn 2009, the Consultative Committee for Ionizing Radiation (CCRI) approved its first supplementary comparison, to be organized by the ENEA (as the pilot laboratory), for the measurement of the alpha and beta particle surface (i.e. 2 solid angle) emission rate from large area sources of the type used for calibrating surface contamination monitors. Five sources were disseminated to the twenty-three participating laboratories consisting of one each of 241Am, 14C, 147Pm and 90Sr for emission rate measurements, with one additional 90Sr source for the evaluation of source uniformity. Measurements of the radionuclide activity and radionuclidic purity were also made although not strictly required. This report describes the organization of this comparison and the material and measurement methods used. The proposed supplementary comparison reference values (SCRV) for each of the comparison measurands are given, together with the Degrees of Equivalence and their associated uncertainties for each participating laboratory. The results of this supplementary comparison may be used as evidence by participating National Metrology Institutes (NMIs) and Designated Institutes (DIs) when submitting calibration and measurement capabilities (CMCs) for the given radionuclides for similar types of large area sources; this is an important aspect of this comparison, given that only one other international supplementary comparison for surface emission rates had been organized before