Radioactivity monitoring: How the JRC verifies results from monitoring within the European Union

This report provides a brief introduction to Proficiency Tests (PTs) and how they are used to make sure EU citizens are better protected from harmful levels of radioactivity, in support of Euratom Treaty Articles 35 and 36. the ten PTs organised by JRC-Geel in the past 15 years are summarized. The main conclusions from these PTs are stated and suggestions for improvements are presented.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard

Results of a European interlaboratory comparison on gross alpha/beta activity determination in drinking water

An interlaboratory comparison was organised by the Institute for Reference Materials and Measurements (JRC-IRMM) among environmental radioactivity monitoring laboratories for the determination of gross alpha/beta activity concentration in drinking water. Four independent standard methods were used for the determination of the reference values of three different water samples. The performance of participating laboratories was evaluated with respect to the reference values using relative deviations. Sample preparation and measurement methods used by the participating laboratories are described in detail, in particular in the view of method-dependency of the results. Many of the participants’ results deviate by more than two orders of magnitude from the reference values regardless of the techniques used. This suggests that gross methods need revision.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

European Atlas of Natural Radiation

Natural ionizing radiation is considered as the largest contributor to the collective effective dose received by the world population. The human population is continuously exposed to ionizing radiation from several natural sources that can be classified into two broad categories: high-energy cosmic rays incident on the Earth’s atmosphere and releasing secondary radiation (cosmic contribution); and radioactive nuclides generated during the formation of the Earth and still present in the Earth’s crust (terrestrial contribution). Terrestrial radioactivity is mostly produced by the uranium and thorium radioactive families together with potassium. In most circumstances, radon, a noble gas produced in the radioactive decay of uranium, is the most important contributor to the total dose. This Atlas aims to present the current state of knowledge of natural radioactivity, by giving general background information, and describing its various sources. This reference material is complemented by a collection of maps of Europe displaying the levels of natural radioactivity caused by different sources. It is a compilation of contributions and reviews received from more than 80 experts in their field: they come from universities, research centres, national and European authorities and international organizations. This Atlas provides reference material and makes harmonized datasets available to the scientific community and national competent authorities. In parallel, this Atlas may serve as a tool for the public to: • familiarize itself with natural radioactivity; • be informed about the levels of natural radioactivity caused by different sources; • have a more balanced view of the annual dose received by the world population, to which natural radioactivity is the largest contributor; • and make direct comparisons between doses from natural sources of ionizing radiation and those from man-made (artificial) ones, hence to better understand the latter.JRC.G.10-Knowledge for Nuclear Security and Safet

Performance evaluation of a European scale proficiency test on radon-in-water measurements in Europe

In 2018, a Europe wide proficiency test (PT) on measurements of the massic activity of 222Rn in drinking water was organised with the participation of 101 European environmental radioactivity monitoring laboratories. The performance of the participating laboratories was evaluated by comparing submitted results to the reference value using percentage deviation, z-score and zeta-score. It was found that 84% of the participants’ results were within the ±20% reference range. When analysing the zeta score it was found that 76% of the participants' results were acceptable. The accompanied questionnaire and workshop helped to identify practices that could lead to erroneous results. As it was probably the largest scale PT on radon-in-water ever, the evaluation of results is representative of the quality of radon-in-water monitoring in the EU today.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard

Optimization of the liquid scintillation counting technique for the European interlaboratory comparison on gross α/β activity concentrations in water

A liquid scintillation counting (LSC) measurement method optimization for the gross α/β activity analysis in drinking waters with different chemical and radionuclide composition was performed. The optimized method was suitable to provide gross radioactivity results in drinking waters with the levels of the accuracy and precision similar to those obtained using other radioactivity screening techniques. Robust LSC results contributed to the calculation of gross α/β activity reference values of EC-JRC interlaboratory comparison water samples in 2012. Some of the most common errors in the determination of the gross radioactivity using the LSC are presented.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard

Critical remarks on gross alpha/beta activity analysis in drinking waters: Conclusions from a European interlaboratory comparison

The most common gross alpha/beta standard methods used for drinking water analysis are discussed, and sources of interferences are reviewed from a metrological point of view. Our study reveals serious drawbacks of gross methods on the basis of an interlaboratory comparison analyzing commercial mineral water samples with the participation of 71 laboratories. A proposal is made to obtain comparable measurement results using true standardized methods.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

Current Status of Gross Alpha/Beta Activity Analysis in Water Samples: A Short Overview of Methods

Gross alpha/beta measurement is one of the simplest radioanalytical procedures which are applied widely as a screening technique in the field of radioecology, environmental monitoring and industrial applications as well. Due to the uncertainties of gross alpha/beta measurements this method is often the subject of discussions and debates. The aim of this work is to collect information about recently used standard and routine methods concerning gross alpha/beta activity determination in drinking waters in order to get an overview about the current situation and evaluate their possibilities. Sample preparation methods - e.g. evaporation, co-precipitation - and detection systems - e.g. gas flow proportional counting, liquid scintillation counting and scintillation counting - are compared on the ground of literature data. In the course of our work, the following parameters were analyzed and discussed: background, counting efficiency, interferences, sample capacity, minimal detectable activity, typical counting time, time demand of sample preparation.JRC.DG.D.5-Nuclear physic

EC interlaboratory comparison on terrestrial radionuclides in soil

In 2010, 73 laboratories participated in the interlaboratory comparison organized by the Institute for Reference Materials and Measurements on the activity concentrations of 15 radionuclides in soil. Results for the terrestrial radionuclides 40K, 226Ra, 230Th, 232Th, 234U, 235U, and 238U are discussed in this paper. The laboratories' performance varied depending on the radionuclide determined and method used. Gamma-ray spectrometry with respect to 40K is well controlled. However, gamma-ray spectrometry results for other radionuclides, like 226Ra and uranium isotopes, rendered very bad results. This is most probably due to the lack of appropriate corrections in these measurements. In general, better results were obtained by alpha-particle spectrometry, except for the 232Th where the results of gamma-ray spectrometry are significantly better. The most successful method is ICP-MS although used only by two participants for the determination of uranium isotopes.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

Preparation of high resolution 238U alpha-sources by electrodeposition from aqueous solution

The source preparation procedure for high-resolution 238U sources is described in this work. For preparing alpha sources for high-resolution spectrometry many parameters of the electrodeposition had to be optimised such as the type of electrolyte, material and shape of the platinum anode, material of the cathode (backing), surface quality of the cathode, deposited mass, rotation of the anode, current density and the deposition time. This work was done in collaboration between CIEMAT and IRMM within the frame of MetroFission project aiming at the determination of the alpha-emission probabilities of 238U. MetroFission aims to address the measurement challenges posed by 'Generation IV' designs, by testing temperature measurements and materials for suitability, and ensuring sufficient nuclear data and radiation measurement techniques are available.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

Comprehensive study on the technical aspects of sampling, transporting and measuring radon-in-water

The European Commission`s Joint Research Centre organizes proficiency tests (PT) on radon-in-water measurements. In order to optimize sampling, transport and measurement methods many tests and small scale proficiency tests have been performed. The waters from natural springs, wells were sampled on-site in glass bottles then transported cooled to the JRC and collaborating laboratories. For the material characterization standard measurement methods based on gamma-ray spectrometry, emanometry and liquid scintillation counting were used. The influence of sampling, transport and sample handling on radon-loss was tested and quantified. It was observed that parameters like container material, filling height, storage temperature and handling can lead to substantial measurement bias due to radon-loss. This high risk for radon-loss from samples can potentially be a general radioprotection problem as doses to the public may be underestimated. Regular air and road transport can be considered adequate means of transport as they have little influence on radon-loss if a suitable glass sample container with flexible cap is used and that it is completely filled. On the basis of this work, modifications to the related standard as best practices are also proposed.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard