| 1. |
- Barkauskas, Vytenis, et al.
(författare)
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Prediction of the radionuclide inventory in the European Spallation Source target using FLUKA
- 2020
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 471, s. 24-32
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Tidskriftsartikel (refereegranskat)abstract
- The FLUKA code was applied to a simplified model of the tungsten target of the European Spallation Source (ESS) and shown to be suitable for modelling the radionuclide inventory of the ESS target. Two groups of radionuclides were selected based on dose factors and total predicted activities, one immediately after 5 years (designed lifetime of the target) of operation, and the other 10 years after shutdown. The predicted radionuclide production was higher than estimated by other authors for most of the radionuclides considered. The calculated 3H activity was close to the highest values obtained with other spallation models. Particular attention was paid to the evaluation of the production of one of the most toxic radionuclides, 148Gd. Differences in the predicted activities of 148Gd were mainly attributed to differences in the spallation and nuclear evaporation models used.
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| 2. |
- Bernhardsson, Christian, et al.
(författare)
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Environmental radiation baseline around the Belarusian nuclear power plant – assessments in Belarus and Lithuania
- 2023
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Ingår i: Medical Physics in the Baltic States : Proceedings of the 16<sup>th</sup> International Conference on Medical Physics - Proceedings of the 16<sup>th</sup> International Conference on Medical Physics. - 1822-5721. ; , s. 121-125
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Konferensbidrag (refereegranskat)abstract
- Prior to the operation of the first Belarussian nuclear power plant (BelNPP), the baseline of the radiation environment was determined within a radius of about 30 km from BelNPP. This independent assessment was carried out during two expeditions in 2019. In 2022, a similar survey was carried out (during the initialoperation of BelNPP) on the Lithuanian side of the boarder. Here we present the overall project and some general results of the baseline assessments.
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| 3. |
- Bernhardsson, Christian, et al.
(författare)
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ZERO POINT ASSESSMENT OF THE RADIATION ENVIRONMENT – EXAMPLES OF A PROGRAM APPLIED IN SWEDEN (ESS) AND IN BELARUS (BELNPP)
- 2019
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Ingår i: MEDICAL PHYSICS IN THE BALTIC STATES : Proceedings of the 14th International Conference on Medical Physics - Proceedings of the 14th International Conference on Medical Physics. ; , s. 85-88
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Konferensbidrag (refereegranskat)abstract
- Before commissioning of a nuclear facility it is important to determine the baseline of the radiation environment. Such baseline or Zero Point assessments can only,and uniquely, be made before start of operation of the facility and will serve several purposes when the facility is in operation. Here we report on the planning and implementation of such a Zero Point program for achieving high reproducibility and effectiveness of the assessments around two nuclear installations.
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| 4. |
- Eriksson Stenström, Kristina, et al.
(författare)
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Identifying radiologically important ESS-specific radionuclides and relevant detection methods
- 2020
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Bok (refereegranskat)abstract
- The European Spallation Source (ESS) is under construction in the outskirts of Lund in southern Sweden. When ESS has entered the operational phase in a few years, an intense beam of high-energy protons will not only produce the desired spallation neutrons from a large target of tungsten, but a substantial number of different radioactive by-products will also be generated. A small part of these will be released to the environment during normal operation. During an accident scenario, a wide range of gases and aerosols may be released from the tungsten target. The palette of radionuclides generated in the ESS target will differ from that of e.g. medical cyclotrons or nuclear power plants, thus presenting new challenges e.g. in the required environmental monitoring to ensure that dose limits to the public are not exceeded. This project (SSM2018-1636), financed by the Swedish Radiation Safety Authority (SSM), aimed to strengthen competence at Lund University for measurement and analysis of ESS-specific radionuclides. First, an extensive literature review, including modelling as well as experimental analyses, of ESS-relevant radionuclides was performed. We found that radionuclide production in particle accelerators is well-known, while experience with tungsten targets is very limited. As a second part of the project, an independent simplified model of the ESS target sector for the calculations of radionuclide production in the ESS tungsten target was developed using the FLUKA code. We conclude that we have a fairly good agreement with results of other authors, except for 148Gd, and that the calculated radionuclide composition is sensitive to the nuclear interaction models used.In the third part of the project, known environmental measurement technologies for various ESS-relevant radionuclides were reviewed, focussing on pure difficult-to-measure alpha- and beta-emitters. Liquid scintillation counting (LSC) is a suitable technique e.g. for the important beta emitters 3H, 14C, 35S, 31P and 33P. Several ESS radionuclides of relevance for dose estimates have never been investigated by environmental analytical techniques, due to their absence in the normal environment. Alpha spectrometry seems promising for the analysis of alpha-emitting lanthanides, in particular for 148Gd. Among the many types of mass spectrometry techniques, ICP-MS (inductively coupled plasma mass spectrometry) and AMS (accelerator mass spectrometry) seem to be the most suitable for the analysis of long-lived ESS radionuclides in environmental samples (e.g. 243Am and possibly lanthanides for ICP-MS and 10Be, 14C, 32Si, 36Cl, 60Fe and 129I for AMS).Three experimental parts were performed during the project, related to initiation of radioactivity measurements of aerosols at Lund University, mapping of environmental tritium in the Lund area, and establishment of a method to measure tritium in urine followed by a study of tritium in persons presently living or working in Lund. Aerosols were collected at a rural background station (Hyltemossa near Perstorp, northern Skåne) using a high-volume aerosol sampler with automatic filter change (DHA-80, Digitel). Gamma spectrometry measurements of 7Be agreed rather well with results from a nearby air monitoring station (SSM/FOI). Tritium (radioactive hydrogen) is expected to dominate the source term from the ESS target station to the environment. We have performed several investigations to monitor the current situation of tritium in Lund using LSC: the matrices investigated included air humidity, precipitation, pond water, indoor air at one accelerator facility and urine from the general public as well as from persons who may be occupationally exposed to tritium. Environmental tritium was generally very low (<3.4 Bq L-1), with somewhat higher concentration in the springtime than during the rest of the year. Tritium in the vast majority of the 55 urine samples was also very low: only a few exposed workers were found to have up to 11 Bq L-1 in their urine, which still is very low compared to e.g. reactor workers. Suggestions for further actions and work related to measurement and analysis of ESS relevant radionuclides are presented.
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| 5. |
- Eriksson Stenström, Kristina, et al.
(författare)
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PREOPERATIONAL ASSESSMENT OF 14C IN THE VINICINITY OF THE BELARUSIAN NUCLEAR POWER PLANT
- 2021
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Ingår i: Medical Physics in the Baltic States : Proceedings of the 15th International Conference - Proceedings of the 15th International Conference. - 1822-5721. ; , s. 133-137
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Konferensbidrag (refereegranskat)abstract
- As part of an independent assessment of the preoperational radiation environment around the Ostrovets nuclear power plant in Belarus, grass and foodstuffs were collected in 2019 for 14C analysis. The preoperational 14C specific activities in the Ostrovets region were shown to be similar to that of European data from other uncontaminated sites.
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| 6. |
- Pédehontaa-Hiaa, Guillaume, et al.
(författare)
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Evaluation of the region-specific risks of accidental radioactive releases from the European Spallation Source
- 2021
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Ingår i: Medical Physics in the Baltic States : Proceedings of the 15th International Conference on Medical Physics - Proceedings of the 15th International Conference on Medical Physics. - 1822-5721. ; , s. 142-146
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Konferensbidrag (refereegranskat)abstract
- The European Spallation Source (ESS) is a neutron research facility under construction in southern Sweden. The facility will produce a wide range ofradionuclides that could be released into the environment. Some radionuclides are of particular concern such as the rare earth gadolinium-148. In this article, the local environment was investigated in terms of food production and rare earth element concentration in soil. The collected data will later be used to model thetransfer of radioactive contaminations from the ESS.
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| 7. |
- Pédehontaa-Hiaa, Guillaume, et al.
(författare)
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How to detect radionuclides specific to the European Spallation Source in soil samples?
- 2023
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Ingår i: Medical Physics in the Baltic States (2023) : Proceedings of the 16th International Conference on Medical Physics - Proceedings of the 16th International Conference on Medical Physics. ; , s. 115-120
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Konferensbidrag (refereegranskat)abstract
- The European Spallation Source (ESS) is a neutron research facility under construction in southern Sweden. The facility will produce a wide range of radionuclides including 148Gd, 187W, 172Hf, 182Ta and 178nHf that could be released into the environment in an accident scenario. Detection limits for these contaminants in soil were estimated to be in the mg k-1 range for ICP-MS and <3 Bq per 200 ml soil for gamma-ray spectroscopy.
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| 8. |
- Pédehontaa-Hiaa, Guillaume, et al.
(författare)
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Investigation of the limits of detection for specific radionuclides in soil from the European Spallation Source (ESS) using radiometric and mass spectrometric methods
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This study provides information about the concentration of Tungsten (W), Hafnium (Hf) and Tantal (Ta) in the ESS soil and recommendations on the most appropriate sample preparation and measurement technique to assess contamination by these elements. The current levels of W, Hf and Ta measured in this study are in agreement with the estimated values from previous geological surveys. ICP MS showed low limits of detection for W, Hf and Ta and is thus an appropriate technique for environmental monitoring. However, the three metals are difficult to extract from soil and require the use of specific sample preparation methods (based on hydrofluoric acid for example). The transfer of stable W, Hf and Ta from soil to plant is poorly known and only a handful of publications can be found that are relevant to the plants grown around the ESS. The transfer of the radioisotopes of W, Hf and Ta in particular to animals (and man) is even less studied. However, the existing articles indicate a fast excretion of radio-W and radio-Ta while the excretion is slow for radio-Hf.The Minimum Detectable Activity (MDA) for gamma emitter released from the ESS facility will depend not only on the performances of the detection equipment but also on the composition of tungsten target at the time of the release. The determination of limits of detection of ESS related gamma emitters was performed using a strategy based on simulation of spectra. Semi-synthetic gamma spectra were obtained by combining real soil measurements with simulated data for mixtures of ESS radionuclides using the software Nucleonica. The simulation of 187W spectra was used as a proof of concept for the method. With this approach, it is possible to estimate limits of detection by gamma spectroscopy for a given target composition. The limits of detection of four relevant radionuclides were successfully determined for two different compositions of the ESS target and at three different activity concentrations in soil.
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| 9. |
- Pédehontaa-Hiaa, Guillaume, et al.
(författare)
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Region-specific radioecological evaluation of accidental releases of radionuclides from ESS
- 2021
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Bok (refereegranskat)abstract
- Gadolinium-148 is one of the radionuclides of most concern that will be produced in the tungsten target of the European Spallation Source (ESS), as a by-product of the spallation reaction used by the facility to produce neutrons. Since 148Gd a pure alpha emitter, it is both very radiotoxic and difficult to measure. With its half-life of 75 years, it will remain in the environment for a long time if released from the facility during normal operation or after an accident. There are still uncertainties regarding the amounts that actually will be produced by spallation in the tungsten targets of the facility. As Gd-148 does not occur naturally in the environment, there is no information available about its analysis in environmental samples but a few studies provide data from irradiated target material analysed by alpha spectroscopy or inductively coupled plasma mass spectrometry (ICP-MS). This report is a continuation of the SSM project as described in the SSM report 2020:08, entitled “Identifying radiologically important ESS-specific radionuclides and relevant detection methods” that focused on the ESS-related radionuclides that will be the most relevant to study and monitor in the environment as well as the analytical techniques to detect them. The present report focuses on the rare earth elements (REEs), including their radioactive isotopes, in particular Gd-148, and is intended to highlight the knowledge gaps that exist regarding their fate in the specific environment of the ESS area. In the first part of the report, the available literature on radioecological models was reviewed, with emphasis on ESS-related radionuclides. The existing modelling programmes were surveyed as well as the most relevant environmental parameters and experimental radioecological data required to build models specific to the ESS.In the second part of the report, the area in the vicinity of the ESS was surveyed to identify the important producers of foodstuff, what plant species are grown in the area and also the local husbandry and hunting practices, in order to identify critical pathways after a radioactive dispersion into the environment in connection with a potential accident at the ESS. In the third part of this report, after a thorough literature review and preliminary assays, we propose to investigate the use of ICP-MS for assessment of Gd-148 in the event of an accidental release, knowing that this analytical technique is already used for the measurement of stable Gd and REEs in the environment. The existing methods to extract REEs from environmental samples (soil, water, plants, and animal products) and to properly assess their concentration are described in the form of a literature review. The presented examples of methods were selected to fit the type of environment found around the ESS facility and the local agricultural and horticultural practices. A pilot study was also conducted to test extraction and measurement methods on the specific type of soil around ESS. These results are presented at the end of this report.
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