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This paper reports the results obtained during an intercomparison exercise for the determination of difficult to measure radionuclides in activated reactor pressure vessel (RPV) steel samples. In total, eight laboratories participated analysing 14C, 55Fe and 63Ni activity concentrations in RPV steel. In addition, some laboratories also analysed 60Co activity concentrations. Corresponding activity concentrations were also determined using activation calculations. Robust statistical techniques were utilised for the analysis of the results according to ISO 13528 standard. The results showed good agreement for 55Fe and 63Ni results whereas 14C results had significant differences. 60Co results were in quite good agreement.

A need for method validation in radiochemical analyses of decommissioning waste is a challenging task due to lack of commercial reference materials. Participation in an intercomparison exercise is one way for a laboratory to assess their performance and validate their analysis results. A three-year project within the Nordic Nuclear Safety Research (NKS) community was initiated in order to carry out intercomparison exercises on difficult to measure (DTM) radionuclides in real decommissioning waste. Both Nordic and Non-Nordic laboratories participated. This paper reports the results from the final year of the project focusing on beta- and gamma emitter (i.e., easy to measure, ETM) analysis in spent ion exchange resin. The assigned values were derived from the participants’ results according to ISO 13528 standard and the performances were assessed using z scores. The results showed generally good performances for both DTMs and ETMs.

This paper reports the results obtained in a Nordic Nuclear Safety Research project during the second intercomparison exercise for the determination of difficult to measure radionuclides in decommissioning waste. Eight laboratories participated by carrying out radiochemical analysis of 3H, 14C, 36Cl, 41Ca, 55Fe and 63Ni in an activated concrete. In addition, gamma emitters, namely 152Eu and 60Co, were analysed. The assigned values were derived from the submitted results according to ISO 13,528 standard and the performance assessments were determined using z scores. The measured results were compared with activation calculation result showing varying degree of comparability.

An intercomparison exercise was carried out for difficult to measure radionuclidesin activated concrete samples. The results were analysed according to ISO 13528 standard. The performance assessment was carried out using z score. Report includes an overview of the radioanalytical procedures, preliminary and final results, and performance assessments.

EURADOS Working Group 6 has organized an intercomparison exercise on the use of the ICRP Reference Computational Phantoms with radiation transport codes. This paper summarizes the results of a specific task from the intercomparison exercise modelling internal radiation sources. The quantities to be calculated were absorbed fractions and specific absorbed fractions for monoenergetic photon and electron sources as well as S-values for two radionuclides in four source organs. Twelve participants from eleven countries participated in this specific task using the Monte Carlo radiation transport codes FLUKA, Geant4, the MCNP code family, PenEasy, TRIPOLI-4 and VMC. Although some participants provided initial solutions in good agreement with the master solution evaluated by the organizers, differences of factors or even orders of magnitude were also found. Following feedback from the organizer, most participants submitted revised solutions that were mostly in better agreement with the master solution, although this was not always the case. Some initial and revised results are discussed in detail in this paper, and the reasons of mistakes are described as far as they were revealed by the participants. A full account of all results is presented in specific annexes as supplemental material.

The EC Directive 2013/51/EURATOM of 22 October 2013 represents the first time that a radon limit for drinking water has been proposed. Transposition of this Directive into Spanish legislation was by means of the recent RD 314/2016 which sets a limit value of 500 Bq l?1 for radon (222Rn) in water for human consumption while that in Romanian legislation the Law 301/2015 provides a limit value of 100 Bq l-1 for 222Rn concentration in water for human consumption as well as a total effective dose of 0.1 mSv y-1 from all radionuclides present in water (same dose value established by Spanish law). For several years, both in Romania and in Spain, there have been campaigns to measure the concentration of 222Rn in waters of different origins in order to determine the possible exposure of the population through this irradiation path, and also to use the presence of radon dissolved in water as a source of indoor radon in thermal spa facilities, and also as a tracer of dynamic processes (C. Sainy et al., Sci. Tot. Envir. 543, 460 (2016); 1). In this article, an assessment of the results from measurement campaigns in both countries will be presented and compared. In addition, the different measurement techniques used will be described, and the description of an intercomparison exercise on radon measurement in water organized by the Environmental Radioactivity Laboratory of the University of Cantabria (LaRUC) will be presented, in order to evaluate the quality of the performance of the techniques used. This work was partially supported by the project ID P_37_229, Contract No. 22/01.09.2016, with the title Smart Systems for Public Safety through Control and Mitigation of Residential Radon linked with Energy Efficiency Optimization of Buildings in Romanian Major Urban Agglomerations SMART-RAD-EN of the POC Programme.

We are presenting an initial evaluation of the outcomes of the FAIRMODE & AQUILA intercomparison exercise (IE) on spatial representativeness (SR). To the best of our knowledge, this study provides the first attempt to quantitatively compare the range of methods used for estimating the spatial representativeness of air quality monitoring stations in Europe. As a common working basis, a shared dataset has been selected comprising modelling data and auxiliary information from the city of Antwerp. Based on this, 11 teams from 10 different countries provided their SR estimates for PM10 and NO2 at one traffic site, and for PM10, NO2 and O3 at two urban background sites. The main objective of this exercise was to evaluate the possible variety of spatial representativeness results obtained by applying the range of different contemporary approaches to a jointly used example case study. The results of the IE revealed a considerable range of variation between the different SR estimates - not only in terms of the extent and position of the SR perimeters, but also in the technical procedures and the extent of input data effectively used. These outcomes do also underline the need for (i) a more harmonized definition of the concept of “the area of representativeness” and (ii) consistent and transparent criteria used for its quantification. © 2018 Hungarian Meteorological Service. All Rights Reserved.

Hydrogen generation during the progression of an accident in a nuclear reactor and its release into the containment comprise an important safety concern in the management of severe accidents in nuclear power plants. The distribution of hydrogen within the containment has important bearing on possibility, mode, and consequence of combustion in the containment. Hence, several small-and large-scale facilities have been built to study the distribution of released hydrogen. Further, several numerical studies and intercomparison exercises on hydrogen distribution have been carried out. The present review summarizes the experimental and numerical studies on hydrogen distribution and suggests opportunities for further studies. � 2015 Taylor and Francis Group, LLC.

International audience; In the context of the decrease in the eye lens dose limit for occupational exposure to 20 mSv per year stated by the recent revision of the European Basic Safety Standards Directive 2013/59/EURATOM, the European Radiation Dosimetry Group (EURADOS) has organised in 2014, for the first time, an intercomparison exercise for eye lens dosemeters. The main objective was to assess the capabilities of the passive eye lens dosemeters currently in use in Europe for occupational monitoring in medical fields. A total of 20 European individual monitoring services from 15 different countries have participated. The dosemeters provided by the participants were all composed of thermoluminescent detectors, of various types and designs. The irradiations were carried out with several photon fields chosen to cover the energy and angle ranges encountered in medical workplace. Participants were asked to report the doses in terms of H-p(3) using their routine protocol. The results provided by each participant were compared with the reference delivered doses. All the results were anonymously analysed. Results are globally satisfactory since, among the 20 participants, 17 were able to provide 90 % of their response in accordance with the ISO 14146 standard requirements.

International audience; Two series of activity standards of Co-60 in cast steel matrix, developed for the calibration of gamma-ray spectrometry systems in the metallurgical sector, were characterised using a European interlaboratory comparison among twelve National Metrology Institutes and one international organisation. The first standard, consisting of 14 disc shaped samples, was cast from steel contaminated during production ("originally"), and the second, consisting of 15 similar discs, from artificially-contaminated ("spiked") steel. The reference activity concentrations of Co-60 in the cast steel standards were (1.077 +/- 0.019) Bq g(-1) on 1 January 2013 12h00 UT and (1.483 +/- 0.022) Bq g(-1) on 1 June 2013 12h00 UT, respectively.

This work describes the outcomes of the COST Action-TU1301 “NORM4Building” intercomparison on the determination of natural radioactivity in ceramics. Twenty-two laboratories involved in the intercomparison are evaluated for their performance using robust statistics. The reference values of 226 Ra ( 214 Bi and 214 Pb) are determined to be 122 ± 11 Bq kg −1 and 124 ± 14 Bq kg −1 , respectively and in secular equilibrium in the uranium chain while the reference values of 232 Th ( 228 Ac) is determined to be 61 ± 6 Bq kg −1 and that of 40 K was determined to be 955 ± 40 Bq kg −1 . Although the aim of the exercise was to determine the activity concentration of 226 Ra, 232 Th and 40 K and evaluation of the “Activity Concentration Index”, laboratories were asked to report complete characterization of natural radionuclides. The results of this exercise pointed out a good performance among laboratories since the percentage of the acceptable results were above 90% for the radionuclides of interest. Based on these results, considering the systematic rejection of the results reported from a few laboratories we emphasize the need for quality control procedures.

The performance and the uncertainty of receptor models (RMs) were assessed in intercomparison exercises employing real-world and synthetic input datasets. To that end, the results obtained by different practitioners using ten different RMs were compared with a reference. In order to explain the differences in the performances and uncertainties of the different approaches, the apportioned mass, the number of sources, the chemical profiles, the contribution-to-species and the time trends of the sources were all evaluated using the methodology described in Bells et al. (2015). In this study, 87% of the 344 source contribution estimates (SCEs) reported by participants in 47 different source apportionment model results met the 50% standard uncertainty quality objective established for the performance test. In addition, 68% of the SCE uncertainties reported in the results were coherent with the analytical uncertainties in the input data. The most used models, EPA-PMF v.3, PMF2 and EPA-CMB 8.2, presented quite satisfactory performances in the estimation of SCEs while unconstrained models, that do not account for the uncertainty in the input data (e.g. APCS and FA-MLRA), showed below average performance. Sources with well-defined chemical profiles and seasonal time trends, that make appreciable contributions (>10%), were those better quantified by the models while those with contributions to the PM mass close to 1% represented a challenge. The results of the assessment indicate that RMs are capable of estimating the contribution of the major pollution source categories over a given time window with a level of accuracy that is in line with the needs of air quality management. (C) 2015 The Authors. Published by Elsevier Ltd.

An intercomparison exercise on passive samplers (PSs) was organized in summer 2010 for the measurement of selected metals, polycyclic aromatic hydrocarbons (PAHs) and pesticides in surface waters. Various PSs were used and compared at 2 rivers sites and one marine lagoon. A total of 24 laboratories participated. We present selected significant outputs from this exercise, including discussion on quality assurance and quality control for PSs, the interlaboratory variability of field blanks, time weighted average water concentrations and its uncertainties, the representativity of DGT samples, the ability of PSs to lower limits of detection, PAH fingerprints in various PSs compared with spot samples, and the relevance of the permeability reference compounds (PRC) approach for POCIS with pesticides. These in situ intercomparison exercises should enable to progress on the harmonization of practices for the use of passive sampling, especially for priority chemical monitoring and regulatory programs in compliance with the Water Framework Directive (WFD) and Marine Strategy Framework Directive (MSFD).

Within the project "Environmental Modelling for Radiation Safety" (EMRAS) organized by the IAEA in 2003 experimental data of 131I measurements following the Chernobyl accident in the Plavsk district of Tula region, Russia were used to validate the calculations of some radioecological transfer models. Nine models participated in the inter-comparison. Levels of 137Cs soil contamination in all the settlements and 131I/137Cs isotopic ratios in the depositions in some locations were used as the main input information. 370 measurements of 131I content in thyroid of townspeople and villagers, and 90 measurements of 131I concentration in milk were used for validation of the model predictions. A remarkable improvement in models performance comparing with previous inter-comparison exercise was demonstrated. Predictions of the various models were within a factor of three relative to the observations, discrepancies between the estimates of average doses to thyroid produced by most participant not exceeded a factor of ten. © 2009 Elsevier Ltd.

C-14 measurement uses a number of standards and reference materials with different properties. Historically the absolute calibration of C-14 measurement was tied to 1890 wood, through the 'primary' standard of NBS-OxI (produced by the National Bureau of Standards, now NIST - National Institute of Standards and technology) subsequently replaced by NBS-OxII. These are both internationally calibrated and certified materials, whose C-14 activities are known absolutely.A second tier of materials, often called secondary standards or reference materials, and including internationally recognised materials such as ANU-sucrose (now also IAEA-C6), Chinese - sucrose and the IAEA C1-C6 series, augmented by additional oxalic acid samples are also used routinely. The activity of these materials has been estimated from large numbers of measurements made by many laboratories. Recently, further natural materials from the Third and Fourth International Radiocarbon Inter-comparisons (TIRI and FIRI) have been added to this list. The activities of these standards and reference materials span both the applied C-14 age range and the chemical composition range of typical samples, but this is not achieved uniformly and there is a continuing need for reference materials for laboratory quality control and measurement-traceability purposes.In this paper, we review the development of C-14 Standards and reference materials and consider the future requirements for such materials within the C-14 AMS community. (C) 2004 Elsevier B.V. All rights reserved.

Results of two intercomparison exercises are reported. In the first one, the participants were asked to determine Cd, Cu, Pb and Zn, at the sub mg mL-1 level, in an acidified aqueous solution. In the second one, the participants were asked to determine mercury (total) in two homogeneous biological samples, hair and fish. The exercises were considered satisfactory and few reported results were discharged (3s criteria).

We are presenting an initial evaluation of the outcomes of the FAIRMODE & AQUILA intercomparison exercise (IE) on spatial representativeness (SR). To the best of our knowledge, this study provides the first attempt to quantitatively compare the range of methods used for estimating the spatial representativeness of air quality monitoring stations in Europe. As a common working basis, a shared dataset has been selected comprising modelling data and auxiliary information from the city of Antwerp. Based on this, 11 teams from 10 different countries provided their SR estimates for PM10 and NO2 at one traffic site, and for PM10, NO2 and O3 at two urban background sites. The main objective of this exercise was to evaluate the possible variety of spatial representativeness results obtained by applying the range of different contemporary approaches to a jointly used example case study. The results of the IE revealed a considerable range of variation between the different SR estimates - not only in terms of the extent and position of the SR perimeters, but also in the technical procedures and the extent of input data effectively used. These outcomes do also underline the need for (i) a more harmonized definition of the concept of “the area of representativeness” and (ii) consistent and transparent criteria used for its quantification.