| 1. |
- Ainsbury, Elizabeth A., et al.
(författare)
-
UNCERTAINTY ON RADIATION DOSES ESTIMATED BY BIOLOGICAL AND RETROSPECTIVE PHYSICAL METHODS
- 2018
-
Ingår i: Radiation Protection Dosimetry. - : OXFORD UNIV PRESS. - 0144-8420 .- 1742-3406. ; 178:4, s. 382-404
-
Tidskriftsartikel (refereegranskat)abstract
- Biological and physical retrospective dosimetry are recognised as key techniques to provide individual estimates of dose following unplanned exposures to ionising radiation. Whilst there has been a relatively large amount of recent development in the biological and physical procedures, development of statistical analysis techniques has failed to keep pace. The aim of this paper is to review the current state of the art in uncertainty analysis techniques across the EURADOS Working Group 10-Retrospective dosimetry members, to give concrete examples of implementation of the techniques recommended in the international standards, and to further promote the use of Monte Carlo techniques to support characterisation of uncertainties. It is concluded that sufficient techniques are available and in use by most laboratories for acute, whole body exposures to highly penetrating radiation, but further work will be required to ensure that statistical analysis is always wholly sufficient for the more complex exposure scenarios.
|
|
| 2. |
- Adliene, Diana, et al.
(författare)
-
Assessment of the environmental contamination with long-lived radionuclides around an operating RBMK reactor station
- 2006
-
Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 90:1, s. 68-77
-
Tidskriftsartikel (refereegranskat)abstract
- The presence of man-made gamma emitting radionuclides in the region within 32 km radius of the Ignalina NPP/Lithuania has been investigated during the period 2001-2004, prior to the closure of the first 4 the two operating RBMK 1500-type reactors. Gamma spectrometric measurements of various terrestrial and aquatic plants as well as of soil samples showed moderate environmental contamination with the fission product Cs-137 and with the neutron activation products Co-60 and Mn-54. Traces of the activation products Zn-65 and Ag-110m were found in the nearest vicinity of the NPP. Activity concentrations were inhomogeneously distributed in the area of interest. Moss and algae samples showed the highest uptake of radionuclides. In addition to the gamma spectrometric measurements, the levels of C-14 were determined in the same bio-indicator samples using accelerator mass spectrometry. (c) 2006 Elsevier Ltd. All rights reserved.
|
|
| 3. |
- Bernhardsson, Christian, et al.
(författare)
-
Assessment of effective dose to an individual carrying materials useful for radiation dosimetry by optically stimulated luminescence
- 2015
-
Ingår i: Medical Physics in the Baltic States : Proceedings of the 12th International Conference on Medical Physics - Proceedings of the 12th International Conference on Medical Physics. - 1822-5721. ; , s. 48-51
-
Konferensbidrag (refereegranskat)abstract
- Optically stimulated luminescence (OSL) from ordinary household salt has proven high potential for very low dose retrospective dosimetry. In the present paper other common place materials are considered and their dosimetric OSL-properties compared with household salt. The potential for assessment of the effective dose to an individual carrying such materials is investigated.
|
|
| 4. |
|
|
| 5. |
- Bernhardsson, Christian, et al.
(författare)
-
Comparative Measurements of the External Radiation Exposure in a 137Cs Contaminated Village in Belarus Based on Optically Stimulated Luminescence in NaCl and Thermoluminescence in LiF.
- 2012
-
Ingår i: Health Physics. - 1538-5159. ; 103:6, s. 740-749
-
Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT: Laboratory studies have shown that ordinary household salt (NaCl) exhibits several promising properties for retrospective dosimetry; e.g., a linear dose response and a low detection limit, down to a few mGy or even less. In an attempt to test NaCl as a dosimeter outside the laboratory, the first results from the use of NaCl as a dosimeter under normal environmental conditions are reported here. For this purpose, special dosimeter kits with NaCl and lithium fluoride (LiF) chips were designed. The dosimeter kits were positioned at different locations in a Chernobyl Cs-contaminated village in Belarus during the summers of 2008, 2009, and 2010. The results from the two luminescent detectors were also compared with those of measurements carried out with a handheld 75 cm NaI(Tl) detector and with a 8 dm high pressure ionization chamber. The radiation level in the village was inhomogeneous, and depending on the type of house and countermeasures carried out, the ambient dose rate inside and around the houses varied between 0.05 μSv h and 0.50 μSv h. Based on the different measurements, the annual external effective dose to a hypothetical adult population in the village was estimated as 1-1.5 mSv y. Detector readings from the two luminescent materials correlated relatively strongly to that of the ambient survey NaI(Tl) detector. After three repeated surveys using similar dosimeter kits for prospective dosimetry, the potential use of ordinary household salt as a complement to other techniques for retrospective dose estimations is more evident, and shortcomings of the technique have been identified.
|
|
| 6. |
- Bernhardsson, Christian, et al.
(författare)
-
Environmental radiation baseline around the Belarusian nuclear power plant – assessments in Belarus and Lithuania
- 2023
-
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
-
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.
|
|
| 7. |
- Bernhardsson, Christian, et al.
(författare)
-
Household salt as a retrospective dosemeter using optically stimulated luminescence.
- 2009
-
Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 1432-2099 .- 0301-634X. ; 48, s. 21-28
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this work was to investigate the potential of a selection of household salts (NaCl) as a retrospective dosemeter for ionising radiation using optically stimulated luminescence (OSL). The OSL-response of five brands of salt to an absorbed dose in the range from 1 mGy to 9 Gy was investigated using a Risø TL/OSL-15 reader and a (60)Co beam, allowing low dose-rate irradiations. The salt was optically stimulated with blue light (lambda = 470 +/- 30 nm) at a constant stimulation power (CW-OSL) of 20 mW cm(-2). A linear dose response relationship was found in the dose range from 1 mGy to about 100 mGy and above that level, the relationship becomes moderately supra-linear, at least up to 9 Gy. Depending on the sensitivity and background signal, the minimum detectable absorbed dose (MDD) for the household salt when kept at sealed conditions varied from 0.2 to 1.0 mGy, for the household salts investigated. In addition to its widespread abundance and availability, the low MDD suggests that household salt should seriously be considered as an emergency dosemeter. However, the OSL-properties of NaCl under normal household usage need to be more properly investigated as well as the variation in sensitivity by the quality of the radiation. A further optimisation of the read-out sequence for various brands of commercially available salt may further improve the sensitivity, in terms of luminescence yield, and the signal reproducibility.
|
|
| 8. |
- Bernhardsson, Christian, et al.
(författare)
-
Household salt (NaCl) for optically stimulated luminescence dosimetry: an overview
- 2021
-
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. 90-94
-
Konferensbidrag (refereegranskat)abstract
- This brief overview of the use of household salt (NaCl) in optically stimulated luminescence (OSL) dosimetry is focusing on the use of NaCl pellets. It is suggested that the most optimal use of household NaCl, in general prospective dosimetry, is to compress the salt grains to pellets and read the radiation induced signal using OSL rather than TL. A summary of the main OSL dosimetric properties is provided for two Swedish household salts, and compared to the OSL properties of 100 different salts from all over the world.
|
|
| 9. |
- Bernhardsson, Christian, et al.
(författare)
-
Measurements of long-term external and internal radiation exposure of inhabitants of some villages of the Bryansk region of Russia after the Chernobyl accident
- 2011
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 1879-1026 .- 0048-9697. ; 409:22, s. 4811-4817
-
Tidskriftsartikel (refereegranskat)abstract
- A Nordic-Soviet programme was initiated in 1990 to evaluate the external and internal radiation exposure of the inhabitants of several villages in the Bryansk region of Russia. This area was one of the number of areas particularly affected by the nuclear accident at the Chernobyl Nuclear Power Plant in 1986. Measurements were carried out yearly until 1998 and after that more irregularly; in 2000, 2006 and 2008 respectively. The effective dose estimates were based on individual thermoluminescent dosemeters and on in vivo measurements of the whole body content of (137)Cs (and (134)Cs during the first years of the programme). The decrease in total effective dose during the almost 2 decade follow-up was due to a continuous decrease in the dominating external exposure and a less decreasing but highly variable exposure from internal irradiation. In 2008, the observed average effective dose (i.e. the sum of external and internal exposure) from Chernobyl (137)Cs to the residents was estimated to be 0.3mSvy(-1). This corresponds to 8% of the estimated annual dose in 1990 and to 1% of the estimated annual dose in 1986. As a mean for the population group and for the period of the present study (2006-2008), the average yearly effective dose from Chernobyl cesium was comparable to the absorbed dose obtained annually from external exposure to cosmic radiation plus internal exposure to naturally occurring radionuclides in the human body. Our data indicate that the effective dose from internal exposure is becoming increasingly important as the body burdens of Chernobyl (137)Cs are decreasing more slowly than the external exposure. However, over the years there have been large individual variations in both the external and internal effective doses, as well as differences between the villages investigated. These variations and differences are presented and discussed in this paper.
|
|
| 10. |
- Bernhardsson, Christian, et al.
(författare)
-
OSL in Household Salt (NaCl) for Environmental, Occupational and Medical Dosimetry
- 2009
-
Ingår i: Medical Physics In The Baltic States: Proceedings Of The 7th International Conference On Medical Physics. - 1822-5721. ; , s. 65-68
-
Konferensbidrag (refereegranskat)abstract
- The recent progress in our work to implement salt (NaCl) as a dosemeter is presented. Laboratory investigations have indicated a linear dose response from 1 mGy to about 100 mGy and detection limits down to 0.1 mGy. Investigations in the clinic comparing TL-dosimetry in LiF and OSL in NaCl have indicated a similar dose response for the two dosemeters at different photon energies. Field studies with stationary dosemeter kits containing TLDs (LiF) and NaCl suggests that salt is also a good candidate for environmental monitoring of radiation.
|
|
| 11. |
|
|
| 12. |
- Bernhardsson, Christian, et al.
(författare)
-
Spatial variability of the dose rate from (137)Cs fallout in settlements in Russia and Belarus more than two decades after the Chernobyl accident.
- 2015
-
Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 149, s. 144-149
-
Tidskriftsartikel (refereegranskat)abstract
- Radionuclides from the 1986 Chernobyl accident were released and dispersed during a limited period of time, but under widely varying weather conditions. As a result, there was a high geographical variation in the deposited radioactive fallout per unit area over Europe, depending on the released composition of fission products and the weather during the 10 days of releases. If the plume from Chernobyl coincided with rain, then the radionuclides were unevenly distributed on the ground. However, large variations in the initial fallout also occurred locally or even on a meter scale. Over the ensuing years the initial deposition may have been altered further by different weathering processes or human activities such as agriculture, gardening, and decontamination measures. Using measurements taken more than two decades after the accident, we report on the inhomogeneous distribution of the ground deposition of the fission product (137)Cs and its influence on the dose rate 1 m above ground, on both large and small scales (10(ths) of km(2) - 1 m(2)), in the Gomel-Bryansk area close to the border between Belarus and Russia. The dose rate from the deposition was observed to vary by one order of magnitude depending on the size of the area considered, whether human processes were applied to the surface or not, and on location specific properties (e.g. radionuclide migration in soil).
|
|
| 13. |
- Bernhardsson, Christian, et al.
(författare)
-
ZERO POINT ASSESSMENT OF THE RADIATION ENVIRONMENT – EXAMPLES OF A PROGRAM APPLIED IN SWEDEN (ESS) AND IN BELARUS (BELNPP)
- 2019
-
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
-
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.
|
|
| 14. |
- Bukartas, Antanas, et al.
(författare)
-
Accuracy of a Bayesian technique to estimate position and activity of orphan gamma-ray sources by mobile gamma spectrometry : Influence of imprecisions in positioning systems and computational approximations
- 2022
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 17:6 June
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to investigate the effects of experimental data on performance of a developed Bayesian algorithm tailored for orphan source search, estimating which parameters affect the accuracy of the algorithm. The algorithm can estimate the position and activity of a gamma-ray point source from experimental mobile gamma spectrometry data. Bayesian estimates were made for source position and activity using mobile gamma spectrometry data obtained from one 123% HPGe detector and two 4-l NaI(Tl) detectors, considering angular variations in counting efficiency for each detector. The data were obtained while driving at 50 km/h speed past the sources using 1 s acquisition interval in the detectors. It was found that deviations in the recorded coordinates of the measurements can potentially increase the uncertainty in the position of the source 2 to 3 times and slightly decrease the activity estimations by about 7%. Due to the various sources of uncertainty affecting the experimental data, the maximum predicted relative deviations of the activity and position of the source remained about 30% regardless of the signal-to-noise ratio of the data. It was also found for the used vehicle speed of 50 km/h and 1 s acquisition time, that if the distance to the source is greater than the distance travelled by the detector during the acquisition time, it is possible to use point approximations of the count-rate function in the Bayesian likelihood with minimal deviations from the integrated estimates of the count-rate function. This approximation reduces the computational demands of the algorithm increasing the potential for applying this method in real-time orphan source search missions.
|
|
| 15. |
- Bukartas, Antanas, et al.
(författare)
-
Bayesian algorithm to estimate position and activity of an orphan gamma source utilizing multiple detectors in a mobile gamma spectrometry system
- 2021
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 16:1 January
-
Tidskriftsartikel (refereegranskat)abstract
- To avoid harm to the public and the environment, lost ionizing radiation sources must be found and brought back under the regulatory control as soon as possible. Usually, mobile gamma spectrometry systems are used in such search missions. It is possible to estimate the position and activity of point gamma sources by performing Bayesian inference on the measurement data. The aim of this study was to theoretically investigate the improvements in the Bayesian estimations of the position and activity of a point gamma source due to introduction of data from multiple detectors with angular variations of efficiency. Three detector combinations were tested - a single 123% HPGe detector, single 4l NaI (Tl) detector and a 123% HPGe with 2x4l NaI (Tl) detector combination - with and without angular efficiency variations for each combination resulting in six different variants of the Bayesian algorithm. It was found that introduction of angular efficiency variations of the detectors did improve the accuracy of activity estimation slightly, while introduction of data from additional detectors lowered the signal-to-noise ratio threshold of the system significantly, increasing the stability and accuracy of the estimated source position and activity, for a given signal-to-noise ratio.
|
|
| 16. |
- Chamizo, E., et al.
(författare)
-
Insights into the Pu isotopic composition (239Pu, 240Pu, and 241Pu) and 236U in marshland samples from Madagascar
- 2020
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697. ; 740
-
Tidskriftsartikel (refereegranskat)abstract
- This work provides new insights into the presence of 239Pu, 240Pu, 241Pu, and 236U in the Southern Hemisphere through the study of peat bog cores from marshlands in Madagascar (19°S). 210Pb, 238Pu and 239+240Pu activities were characterized by alpha spectrometry in previous studies. Here, Pu from alpha-spectrometry discs corresponding to 10 peat-bog cores (85 samples) was reassessed for the aim of completing its isotopic composition (239Pu, 240Pu, and 241Pu) by Accelerator Mass Spectrometry. In addition, 236U was studied in a single core exhibiting unusually low 240Pu/239Pu ratios. Integrated 240Pu/239Pu atom ratios in the single cores ranged above and below the (0–30°S) fallout average ratio, 0.173 ± 0.027, from 0.126 ± 0.003 to 0.206 ± 0.002, without a regional pattern, thereby demonstrating the heterogeneous distribution of the 239Pu and 240Pu signal. However, such a variability was not observed for 241Pu/239Pu, ranging from (6 ± 1) · 10−4 to (11 ± 1) · 10−4 and consistently below the (0–30°S) fallout ratio of (9.7 ± 0.3) · 10−4 (2012). The integrated 236U/239Pu atom ratio in the studied core, 0.147 ± 0.005, was also significantly lower than the values reported for the global fallout in the Northern Hemisphere, in the 0.20–0.23 range. Our results point out to stratospheric fallout as the main source of both 236U and 241Pu at the studied site, whereas 239Pu and 240Pu signals show the influence of tropospheric fallout from the low-yield tests conducted in Australia (1952–1958) by United Kingdom and in French Polynesia (1966–1975) by France despite the long relative distances (i.e. about 15,000 and 8500 km). It was also demonstrated that a representative number of samples is necessary in order to assess Pu contamination and its various origins in a specific region in the Southern Hemisphere due to the heterogeneous distribution, and results based on single sample analysis should be interpreted with caution. © 2020 Elsevier B.V.
|
|
| 17. |
- Christiansson, Maria, et al.
(författare)
-
Household salt for retrospective dose assessments using OSL: signal integrity and its dependence on containment, sample collection, and signal readout.
- 2014
-
Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 1432-2099 .- 0301-634X. ; 53:3, s. 559-569
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this work was to determine how a latent optically stimulated luminescence (OSL) signal in irradiated household salt is preserved under various ambient conditions, from the time of exposure to the time of signal readout. The following parameters were examined: optical fading in fluorescent light and under darkroom conditions (red light), thermal stability of the OSL signal during storage in a light-tight container, optical fading in representative container types, and sensitization effects of the OSL signal in exposed household salt. Furthermore, the influence of grain mixing within the saltshaker or salt container was studied by determining the dose gradient within typical salt packages. Finally, the signal integrity of salt irradiated under field conditions in a village in Belarus contaminated by Chernobyl fallout was investigated. The results show that the OSL signal in household salt is preserved in large cardboard box containers, but not in white plastic salt containers or in small portion bags used in, e.g., fast food restaurants. Furthermore, the continuous wave blue OSL signal in household salt does not fade significantly during storage up to 140 days. On the contrary, the signal appears to slowly increase during storage ("inverse fading"). Field tests of two different salt containers (with and without black tape to block light) located in Belarussian households confirmed that the signal is preserved in white plastic salt containers when they are covered with extra light-shielding material.
|
|
| 18. |
- Christiansson, Maria, et al.
(författare)
-
Optimizing A Readout Protocol For Low Dose Retrospective Osl-Dosimetry Using Household Salt
- 2012
-
Ingår i: Health Physics. - 1538-5159. ; 102:6, s. 631-636
-
Tidskriftsartikel (refereegranskat)abstract
- The authors' aim has been to find a single aliquot regenerative dose (SAR) protocol that accurately recovers an unknown absorbed dose in the region between 1-250 mGy in household salt. The main investigation has been conducted on a specific mine salt (>98.5% NaCl) intended for household use, using optical stimulation by blue LED (lambda = 462 nm). The most accurate dose recovery for this brand of salt is found to be achieved when using Peak Signal Summing (PSS) of the OSL-decay and a preheat temperature of 200 degrees C after the test dose. A SAR protocol for the household salt with preset values of regenerative doses (R1-R5) and a test dose (TED) of 17 mGy is also suggested here. Under laboratory conditions, the suggested protocol recovers unknown absorbed doses in this particular brand within 5% (2 SD) in the dose range between 1-250 mGy. This is a very promising result for low dose applications of household salt as a retrospective dosimeter after a nuclear or radiological event. Health Phys. 102(6):631-636;2012
|
|
| 19. |
- Christiansson, Maria, et al.
(författare)
-
OSL in NaCl vs. TL in LiF for absorbed dose measurements and radiation quality assessment in the photon energy range 20 keV to 1.3 MeV
- 2018
-
Ingår i: Radiation Measurements. - : Elsevier BV. - 1350-4487. ; 112, s. 11-15
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to determine the photon energy dependence of absorbed dose measurements, in a comparison of optically stimulated luminescence (OSL) in NaCl with thermoluminescence (TL) in LiF:Mg,Cu,P. The comparisons were made at exposure to ionizing radiation in the photon energy range 20 keV to 1.3 MeV. Specially designed dosemeter kits containing both NaCl and LiF were used under i) laboratory conditions using defined radiation fields, ii) laboratory conditions using sealed point sources mimicking unintentional exposures, and iii) field conditions in areas in Japan that were affected by the Fukushima Daiichi nuclear disaster in 2011. The dosemeter kits used in Japan showed that absorbed doses as low as 100 μGy can be assessed from the OSL signal in NaCl. The ratio of the dosemeter readings using OSL in NaCl and TL in LiF increases after irradiation at lower photon energies (less than a few hundred keV) as determined under laboratory conditions. Compensating for this energy dependence of the absorbed dose determinations obtained from OSL in NaCl would thus require an energy-dependent conversion factor for photon energies below 600 keV. On the other hand, the difference in the photon energy dependence between NaCl and LiF may be used to assess the mean effective energy of the photon field. The signal ratios between NaCl and LiF after exposure to radiation in the Fukushima Dashii contaminated areas in Japan, 1.67 ± 0.26 (2013) and 1.63 ± 0.32 (2015), indicate that the mean photon energy in this area was 300–400 keV during the years of the survey.
|
|
| 20. |
- Christiansson, Maria, et al.
(författare)
-
USING AN OPTIMISED OSL SINGLE-ALIQUOT REGENERATIVE-DOSE PROTOCOL FOR LOW-DOSE RETROSPECTIVE DOSIMETRY ON HOUSEHOLD SALT.
- 2011
-
Ingår i: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 144, s. 584-587
-
Tidskriftsartikel (refereegranskat)abstract
- The single-aliquot regenerative-dose (SAR) protocols used in retrospective dosimetry for optically stimulated luminescence measurements have been mainly developed for archaeological and geological dating of quartz and feldspar. The aim in this study is to find a read-out protocol that can generate the most reproducible signal for household salt (NaCl) at absorbed doses below 100 mGy. The relation between the reproducibility of the signal, in terms of the ratio between given absorbed dose and SAR-calculated dose, and parameters such as test-dose pre-heat temperature has been studied. It was found that a temperature of 200°C yielded the best reproducibility in the SAR-calculated dose, which is a somewhat higher pre-heat temperature than what is used for dating of quartz.
|
|
| 21. |
|
|
| 22. |
- Eriksson Stenström, Kristina, et al.
(författare)
-
Environmental levels of radiocarbon in Lund, Sweden, prior to the start of the European Spallation Source
- 2022
-
Ingår i: Radiocarbon. - 0033-8222. ; 64:1, s. 51-56
-
Tidskriftsartikel (refereegranskat)abstract
- The European Spallation Source (ESS) is a neutron-based research facility under construction in Lund in southern Sweden. The spallation reactions will generate not only the desired neutrons, but also many radioactive byproducts, including 14C. As part of the licensing process, and as recommended by the IAEA, various preoperational studies are being carried out, including mapping the “zero-point” radiation environment around the site. As the city of Lund hosts several facilities using 14C-labeled substances, and since temporary and local 14C contamination have been observed in the past, 14C mapping is an important part of these baseline assessments. We here present a summary of 14C levels in various terrestrial environmental samples in Lund and in southern Sweden during the years 2012 to 2020. These environmental F14C do not display significantly elevated levels compared to sites located remote from Lund. We also describe a local 14C contamination event that was detected at the Lund Radiocarbon Dating Laboratory in 2009. Horse-chestnut leaves collected close to the laboratory exhibited F14C values of up to ∼25% above the clean air background. Elevated values of F14C were also found in a short tree-ring series, especially in 2007. The source of this contamination was identified and successfully removed.
|
|
| 23. |
- Eriksson Stenström, Kristina, et al.
(författare)
-
Identifying radiologically important ESS-specific radionuclides and relevant detection methods
- 2020
-
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.
|
|
| 24. |
- Eriksson Stenström, Kristina, et al.
(författare)
-
PREOPERATIONAL ASSESSMENT OF 14C IN THE VINICINITY OF THE BELARUSIAN NUCLEAR POWER PLANT
- 2021
-
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
-
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.
|
|
| 25. |
- Finck, Robert, et al.
(författare)
-
Maximum detection distances for gamma emitting point sources in mobile gamma spectrometry
- 2022
-
Ingår i: Applied Radiation and Isotopes. - : Elsevier BV. - 0969-8043. ; 184
-
Tidskriftsartikel (refereegranskat)abstract
- In this study an algorithm was developed for calculating maximum detectable distance (MDD) for mobile gamma-ray detection of lost sources in-situ for some common mobile spectrometer systems and gamma sources (137Cs and 60Co). The MDD is a function of detector efficiency, vehicle speed, acquisition time interval, radiation background level and accepted frequency of false alarms. To test its accuracy in predicting the MDD experiments were conducted in-situ. Results indicate agreement with experimental mobile detection distance measurements for 60Co and 137Cs point sources. Both the algorithm and the field test show that at a vehicle speed of 50 km/h, the optimal acquisition time intervals range between 3 and 10 s when searching for unshielded sources with activities of 137Cs and 60Co in the order of 100 MBq. Longer acquisition time intervals (20–30 s) are better to detect higher activity sources at the same speed. However, at higher speeds, shorter time intervals should be selected to increase the MDD. The developed algorithm can help select the optimal combination of detectors, vehicle speed, and instrument settings when using mobile searching in the event of loss of gamma-ray sources.
|
|
| 26. |
- Finck, Robert, et al.
(författare)
-
Underlag för kostnadsberäkning av sanering efter ett utsläpp från en kärnteknisk olycka : Tvärvetenskapligt forskningsprojekt vid Lunds, Göteborgs och Örebro universitet på uppdrag av Myndigheten för samhällsskydd och beredskap
- 2023
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Direkta saneringskostnader efter en kärnteknisk olycka för ett typiskt svenskt bostadsområde med enfamiljshus uppskattades genom att skicka ett underlag liknande en offertförfrågan till en entreprenör med verksamhet riktad mot bl.a. konventionell sanering av fastigheter. Det fiktiva uppdraget omfattade en rad saneringsmetoder som tidigare beskrivits i olika handböcker för sanering av radioaktiv beläggning av mark och ytor. Kostnader för olika saneringsmetoder, samt i vissa fall övriga kommentarer av värde för ett saneringsuppdrag, sammanställs i denna rapport. Sanering av en fastighet med ett friliggande enfamiljshus i ett villaområde bedöms medföra en direkt kostnad av drygt 750 000 kronor (i 2021 års prisnivå), exklusive transport och deponikostnader av avfall som genererats av saneringen samt andra tillkommande infrastrukturkostnader. Detta belopp kan justeras upp till 1 miljon kronor när andelen i transport-, deponi- och infrastrukturkostnader inkluderas, baserat på uppskattningar gjorda efter Fukushimaolyckan i Japan. För ett typiskt svenskt bostadsområde med enfamiljshus svarar denna kostnad mot ca 765 miljoner kronor per kvadratkilometer i 2021 års prisnivå. I beräkningen ingår inte den enskildes kostnader. Inkluderas också de enskilt drabbades kostnader bedöms den totala kostnaden för sanering av typiska svenska bostadsområden med enfamiljshus bli en miljard kronor per kvadratkilometer.
|
|
| 27. |
- Geber-Bergstrand, Therése, et al.
(författare)
-
Optically stimulated luminescence (OSL) dosimetry in irradiated alumina substrates from mobile phone resistors
- 2018
-
Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 57:1, s. 69-75
-
Tidskriftsartikel (refereegranskat)abstract
- In this study the dosimetric properties of alumina (Al2O3) substrates found in resistors retrieved from mobile phones were investigated. Measurements of the decline of optically stimulated luminescence (OSL) generated following exposure of these substrates to ionising radiation showed that 16% of the signal could still be detected after 2 years (735 days). Further, the magnitude of the regenerative dose (calibration dose; Di) had no impact on the accuracy of dose estimates. Therefore, it is recommended that the Di be set as low as is practicable, so as to accelerate data retrieval. The critical dose, DCL, and dose limit of detection, DDL, taking into account the uncertainty in the dose–response relation as well as the uncertainty in the background signal, was estimated to be 7 and 13 mGy, respectively, 1 h after exposure. It is concluded that given the significant long-term component of fading, an absorbed dose of 0.5 Gy might still be detectable up to 6 years after the exposure. Thus, OSL from alumina substrates can be used for dosimetry for time periods far in excess of those previously thought.
|
|
| 28. |
- Geber, Therese, et al.
(författare)
-
Desiccants for retrospective dosimetry using optically stimulated luminescence (OSL)
- 2015
-
Ingår i: Radiation Measurements. - : Elsevier BV. - 1879-0925 .- 1350-4487. ; 78, s. 17-22
-
Tidskriftsartikel (refereegranskat)abstract
- Optically stimulated luminescence (OSL) was used to test different kinds of desiccants for their potential use in retrospective dosimetry. Desiccants are used for the purpose of absorbing liquids and can be found in a number of items which may be found in the immediate environment of a person, including hand bags, drug packages, and the vehicles of rescue service teams. Any material exhibiting OSL properties suitable for retrospective dosimetry is a useful addition to the existing dosimetry system available in emergency preparedness. Eleven kinds of desiccants were investigated in order to obtain an overview of the fundamental OSL properties necessary for retrospective dosimetry. Measurements were made using a Rise TL/OSL reader and irradiations were achieved with the Sr-90/Y-90 source incorporated in the reader. Several of the desiccants exhibited promising properties as retrospective dosemeters. Some of the materials exhibited a strong as-received signal, i.e. without any laboratory irradiation, but the origin of this signal has not yet been established. The minimum detectable dose ranged from 8 to 450 mGy for ten of the materials and for one material (consisting of natural clay) the minimum detectable dose was 1.8 Gy.
|
|
| 29. |
- Geber, Therese, et al.
(författare)
-
Retrospective dosimetry using OSL of tooth enamel and dental repair materials irradiated under wet and dry conditions.
- 2012
-
Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 1432-2099 .- 0301-634X. ; 51:4, s. 443-449
-
Tidskriftsartikel (refereegranskat)abstract
- Following a radiological or nuclear emergency event, there is a need for quick and reliable dose estimations of potentially exposed people. In situations where dosimeters are not readily available, the dose estimations must be carried out using alternative methods. In the present study, the optically stimulated luminescence (OSL) properties of tooth enamel and different dental repair materials have been examined. Specimens of the materials were exposed to gamma and beta radiation in different types of liquid environments to mimic the actual irradiation situation in the mouth. Measurements were taken using a Risø TL/OSL reader, and irradiations were made using a (90)Sr/(90)Y source and a linear accelerator (6 MV photons). Results show that the OSL signal from tooth enamel decreases substantially when the enamel is kept in a wet environment. Thus, tooth enamel is not reliable for retrospective dose assessment without further studies of the phenomenon. Dental repair materials, on the other hand, do not exhibit the same effect when exposed to liquids. In addition, dose-response and fading measurements of the dental repair materials show promising results, making these materials highly interesting for retrospective dosimetry. The minimum detectable dose for the dental repair materials has been estimated to be 20-185 mGy.
|
|
| 30. |
- Hansson, Mats, et al.
(författare)
-
VISUALISATION AND QUANTIFICATION OF LUNG CONTENT OF RADIONUCLIDES ASSOCIATED WITH NUCLEAR AND RADIOLOGICAL EMERGENCIES.
- 2011
-
Ingår i: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 145, s. 341-350
-
Tidskriftsartikel (refereegranskat)abstract
- In a situation when radionuclides accidentally or deliberately are dispersed in the environment, there is a need for rapid investigation of the internal contamination in exposed individuals. In this work, the possibilities of visualising and quantifying uptakes of different radionuclides in the lung region of an adult individual using gamma camera systems have been examined, mainly on a two-headed stationary clinical gamma camera. An anthropomorphic phantom was used to mimic acute lung uptakes in three different body sizes. The gamma camera was calibrated with the lung inserts filled with a homogeneous solution of (99)Tc(m), (46)Sc and (32)P, or with point sources of (241)Am, (57)Co, (85)Sr, (137)Cs and (90)Sr/(90)Y. It was found that for the stationary gamma camera the minimum detectable activity in the lungs using a 5-min acquisition time ranged from 0.53 kBq for (46)Sc to 50 kBq for (32)P. Furthermore, the point sources of (137)Cs, (60)Co and (90)Sr/(90)Y (0.16, 0.80 and 2.2 MBq, respectively) located in the lung insert of the phantom, could be clearly visualised, exhibiting distinct intensity maxima. It is thus concluded that gamma camera systems can be useful for rapid assessment of acute intakes of radionuclides associated with emergency preparedness, both in terms of localisation and quantification.
|
|
| 31. |
- Henricsson, Fredrik, et al.
(författare)
-
A biokinetic study of (209)Po in man.
- 2012
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 1879-1026 .- 0048-9697. ; 437C, s. 384-389
-
Tidskriftsartikel (refereegranskat)abstract
- Five adult volunteers participated in a biokinetic study of radioactive polonium. Portions of about 10Bq of (209)Po were orally administrated to four of the volunteers in a single ingestion. The fifth volunteer ingested a daily amount of 53mBq of 209Po for 243d to study the time to achieve equilibrium between intake and excretion for protracted intakes. For the subjects ingesting single intakes of (209)Po complete sampling of urine and feces was subsequently collected the first few days upon the ingestion. The samples were processed with radiochemical extraction and analyzed with alpha spectrometry. In the study, the maximum daily excretion rates in feces were 18-50% of the ingested activity, observed within 3d after intake. Regarding the urine excretion, the daily excretion peaked, on average, at 0.15-1% of the ingested activity within two days upon intake. These results indicate an average gastro-intestinal uptake fraction of 0.46±0.08, which agrees well with earlier biokinetic studies of polonium in man.
|
|
| 32. |
- Hinrichsen, Yvonne, et al.
(författare)
-
Comparison of experimental and calculated shielding factors for modular buildings in a radioactive fallout scenario
- 2018
-
Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X. ; 189, s. 146-155
-
Tidskriftsartikel (refereegranskat)abstract
- Experimentally and theoretically determined shielding factors for a common light construction dwelling type were obtained and compared. Sources of the gamma-emitting radionuclides 60Co and 137Cs were positioned around and on top of a modular building to represent homogeneous fallout. The modular building used was a standard prefabricated structure obtained from a commercial manufacturer. Four reference positions for the gamma radiation detectors were used inside the building. Theoretical dose rate calculations were performed using the Monte Carlo code MCNP6, and additional calculations were performed that compared the shielding factor for 137Cs and 134Cs. This work demonstrated the applicability of using MCNP6 for theoretical calculations of radioactive fallout scenarios. Furthermore, the work showed that the shielding effect for modular buildings is almost the same for 134Cs as for 137Cs.
|
|
| 33. |
- Hinrichsen, Yvonne, et al.
(författare)
-
Influence of the migration of radioactive contaminants in soil, resident occupancy, and variability in contamination on isodose lines for typical Northern European houses
- 2019
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9:1
-
Tidskriftsartikel (refereegranskat)abstract
- In the remedial phase following an accidental radioactive release, it is important that soil decontamination measures are carried out on the areas that contribute most to the radiation dose. In this study, the newly developed concept of isodose lines was applied to the area around typical Swedish dwellings to identify these areas. The influence of the most common building materials in Sweden, wood and brick, and the importance of the positions of doors and windows on the isodose lines were demonstrated for specific positions inside the houses, as well as for the entire house, assuming the residents exhibit typical resident occupancy. Decontamination of the areas within certain isodose lines was shown to result in a greater dose reduction than decontaminating the same area of soil within a certain distance of the house. Furthermore, the impact of vertical migration of the radioactive contaminants in the soil on the isodose lines was studied, showing that the area enclosed by isodose lines decreases over time as the contaminants migrate deeper into the soil. The resulting isodose lines and their change over time are dominated by the downward movement of the contamination in the upper layer of soil. The impact of the variability in contamination on the final isodose lines and their dependence on building materials are demonstrated.
|
|
| 34. |
- Hinrichsen, Yvonne, et al.
(författare)
-
Maximizing avertable doses with a minimum amount of waste for remediation of land areas around typical single family houses after radioactive fallout based on Monte Carlo simulations
- 2021
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322.
-
Tidskriftsartikel (refereegranskat)abstract
- The uncontrolled release of long-lived radioactive substances from nuclear accidents can contaminate inhabited land areas. The removal of topsoil is an important method for reducing future radiation exposure but can also generate a large amount of waste that needs safe disposal. To the best of our knowledge, previous studies have determined the optimal depth of topsoil removal but not the size of the area designated for this measure. For this purpose, this study performed Monte Carlo simulations of hypothetical 137Cs surface contamination on various ground areas in a typical northern European suburban area. The goal was to study the size of the areas needed and amount of waste generated to achieve a certain relative and absolute dose reduction. The results showed that removing the topsoil from areas larger than 3000 m2 around the houses in the study neighbourhood results in only marginal reduction in radiation exposure. If, on average, 5 cm of topsoil is removed over 3000 m2, then 150 m3 of waste would be generated. However, in this scenario adjacent properties benefit from each other’s decontamination, leading to a smaller amount of waste for a given reduction in future radiation exposure per inhabitant of these dwellings. Additionally, it was shown that topsoil removal over limited areas has a higher impact on the absolute dose reduction at an observation point inside or outside the houses with higher initial dose.
|
|
| 35. |
- Hinrichsen, Yvonne, et al.
(författare)
-
Monte-Carlo simulations of external dose contributions from the surrounding ground areas of residential homes in a typical Northern European suburban area after a radioactive fallout scenario
- 2020
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10:1
-
Tidskriftsartikel (refereegranskat)abstract
- The emissions of 137Cs into the environment from the nuclear accidents in Chernobyl in 1986 and Fukushima in 2011 led to the need to decontaminate large areas to avert radiation doses to the population in the affected areas. To be able to perform cost-effective and sustainable remediation, knowledge is needed about how radiation doses can be minimized through optimized interventions such that the greatest possible reduction in radiation dose is obtained with the smallest possible negative impact on the area. Theoretical calculations have been performed to determine how radiation doses in single family houses in a typical Swedish residential suburb arise from a hypothetical 137Cs deposition on the ground. The intention was to highlight how remediation of different parts of the surroundings affects the radiation dose to the residents in a particular property. A Monte Carlo model of the houses and the environment in a suburban area was set up to allow calculations of the dose contributions from different contaminated ground areas such as their own property, neighbouring properties, streets and surrounding recreational areas. Calculations were performed for eleven observation points inside different rooms of the house and one observation point in the garden outside the house, for four houses in the neighbourhood, and for two types of building construction material. The influence of the time spent in different rooms of the house and the contamination of areas surrounding the house was studied. The results show that in general the main dose contribution originates from their own property, but that a significant part (30–80%, depending on the observation point) can come from other areas, showing the importance of considering the surroundings in remediation actions. More detailed analysis of the results showed that the dose contribution from a source region is in general highly dependent on the position of windows in a brick house, whereas for a wooden house the distance to the source region is also of relevance.
|
|
| 36. |
- Hjellström, Martin, 1993, et al.
(författare)
-
Radioecological transfer factors for Nordic subpopulations for assessment of internal committed dose from atmospheric fallout of radiocaesium (NKS-437)
- 2020
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Measurements of whole body burden of radiocaesium have for a long time been performed in Finland, Norway and Sweden, and used to estimate the impact of the nuclear weapons fallout, as well as the Chernobyl accident, on the populations in the three countries. During this work, it has become evident that the existing data can be analysed to a greater extent than has been possible within the frames of this project. For example, the issue of modelling uptake of caesium from the food chain, based on ecological half-life or aggragated transfer function, Tag(t), in areas where there are reminiscences of previous fallout occasions of the same extent as the present fallout, has to be further investigated. Modelling is a useful tool to check our state of knowledge and reveal gaps in data, which have to be considered in case of future fallout events. This also emphasizes the need for maintaining continuous time-series of measurements on atmospheric deposition as well as the body-burdens in various populations, especially among those known in advance to be sen-sitive to radioecological transfer of fission products.
|
|
| 37. |
- Holstein, Hanna, et al.
(författare)
-
Human metabolism of orally administered radioactive cobalt chloride.
- 2015
-
Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 143, s. 152-158
-
Tidskriftsartikel (refereegranskat)abstract
- This study investigated the human gastrointestinal uptake (f1) and subsequent whole-body retention of orally administered inorganic radioactive cobalt. Of eight adult volunteers aged between 24 and 68 years, seven were given solutions of (57)Co (T1/2 = 272 d) containing a stable cobalt carrier, and six were given carrier-free (58)Co (T1/2 = 71 d). The administered activities ranged between 25 and 103 kBq. The observed mean f1, based on 6 days accumulated urinary excretion sampling and whole-body counting, was 0.028 ± 0.0048 for carrier-free (58)Co, and 0.016 ± 0.0021 for carrier-associated (57)Co. These values were in reasonable agreement with values reported from previous studies involving a single intake of inorganic cobalt. The time pattern of the total retention (including residual cobalt in the GI tract) included a short-term component with a biological half-time of 0.71 ± 0.03 d (average ± 1 standard error of the mean for the two nuclides), an intermediate component with a mean half-time of 32 ± 8.5 d, and a long-term component (observed in two volunteers) with half-times ranging from 80 to 720 d for the two isotopes. From the present data we conclude that for the short-lived (57)Co and (58)Co, more than 95% of the internal absorbed dose was delivered within 7 days following oral intake, with a high individual variation influenced by the transit time of the unabsorbed cobalt through the gastro-intestinal tract.
|
|
| 38. |
- Isaksson, Mats, 1961, et al.
(författare)
-
Absorbed dose rate coefficients for 134Cs and 137Cs with steady-state distribution in the human body : S-coefficients revisited
- 2021
-
Ingår i: Journal of Radiological Protection. - : Institute of Physics Publishing (IOPP). - 0952-4746 .- 1361-6498. ; 41:4, s. 1213-1227
-
Tidskriftsartikel (refereegranskat)abstract
- In the event of an accidental release of radioactive elements from a nuclear power plant, it has been shown that the radionuclides contributing the most to long-term exposure are Cs-134 and Cs-137. In the case of nuclear power plant fallout, with subsequent intake of radionuclides through the food chain, the internal absorbed dose to target tissues from protracted intake of radionuclides needs to be estimated. Internal contamination from food consumption is not caused by a single intake event; hence, the committed equivalent dose, calculated by a dose coefficient or dose per content function, cannot be easily used to calculate the cumulative absorbed dose to relevant target tissues in the body. In this study, we calculated updated absorbed dose rate coefficients for Cs-134 and Cs-137 based on data from the International Commission on Radiological Protection (ICRP) on specific absorbed fractions. The absorbed dose rate coefficients are provided for male and female adult reference phantoms, respectively, assuming a steady-state distribution of Cs that we calculated from the ICRP biokinetic model for Cs. With these coefficients, the absorbed dose to the listed target tissues, separately and to the total body, are related to the number of nuclear transitions (time-integrated activity) in each listed source region. Our new absorbed dose rate coefficients are given for the complete set of target tissues and have not been presented before. They are also provided for aggregated categories of organs to facilitate epidemiological studies.
|
|
| 39. |
|
|
| 40. |
|
|
| 41. |
- Isaksson, Mats, et al.
(författare)
-
Modelling the effective dose to a population from fallout after a nuclear power plant accident—A scenario-based study with mitigating actions
- 2019
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 14:4, s. 1-20
-
Tidskriftsartikel (refereegranskat)abstract
- The radiological consequences of a nuclear power plant (NPP) accident, resulting in the release of radionuclides to the environment, will depend largely on the mitigating actions instigated shortly after the accident. It is therefore important to make predictions of the radiation dose to the affected population, from external as well as internal exposure, soon after an accident, despite the fact that data are scarce. The aim of this study was to develop a model for the prediction of the cumulative effective dose up to 84 years of age based on the ground deposition of 137 Cs that is determined soon after fallout. The model accounts for different assumptions regarding external and internal dose contributions, and the model parameters in this study were chosen to reflect various mitigating actions. Furthermore, the relative importance of these parameters was determined by sensitivity analysis. To the best of our knowledge, this model is unique as it allows quantification of both the external and the internal effective dose using only a fallout map of 137 Cs after a nuclear power plant accident. The cumulative effective dose over a period of 50 years following the accident per unit 137 Cs deposited was found to range from 0.14 mSv/kBq m -2 to 1.5 mSv/kBq m -2 , depending on the mitigating actions undertaken. According to the sensitivity analysis, the most important parameters governing the cumulative effective dose to various adult populations during 50 years after the fallout appear to be: the correlation factor between the local areal deposition of 137 Cs and the maximum initial ambient dose rate; the maximum transfer from regional average fallout on the ground to body burden; the local areal deposition of 137 Cs; and the regional average 137 Cs deposition. Therefore, it is important that mapping of local 137 Cs deposition is carried out immediately after fallout from a nuclear power plant accident, followed by calculations of radiation doses for different scenarios using well-known parameters, in order to identify the most efficient mitigation strategies. Given this 137 Cs mapping, we believe our model is a valuable tool for long-term radiological assessment in the early phase after NPP accidents.
|
|
| 42. |
|
|
| 43. |
|
|
| 44. |
- Isaksson, Mats, et al.
(författare)
-
Stråldosen till boende i nedfallsdrabbade områden: Preliminära uppskattningar efter svenska förhållanden
- 2019
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Utifrån modeller som tagits fram efter radioekologiska studier av svenska förhållanden utförda efter Tjernobylolyckan 1986 visar preliminära beräkningar att de avstyrda stråldoser som kan åstadkommas med sanering av byggnadshus respektive strikta livsmedelsrestriktioner är relativt lika (ca 25%). En kombination av dessa åtgärder kan teoretiskt sänka den summerade stråldosen med 50% under ett 50-årsperspektiv efter nedfallet. Dessa värden har utgått från en genomsnittlig dosreducerande effekt på 50% av en saneringsinsats på en typisk svensk bostad. I det pågående projektet kommer mer detaljerade studier kring saneringseffektvitetens roll i den avstyrda stråldosen över lång sikt att studeras vidare.
|
|
| 45. |
- Jönsson, Mattias, et al.
(författare)
-
Modelling the external radiation exposure from the Chernobyl fallout using data from the Swedish municipality measurement system
- 2017
-
Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 178-179, s. 16-27
-
Tidskriftsartikel (refereegranskat)abstract
- In connection with the Chernobyl fallout and the subsequent deposition of radionuclides in Sweden, Swedish municipalities launched a measurement program to monitor the external radiation exposure. This program encompasses measurements of the ambient dose equivalent rate 1 m above ground at selected locations, and repeats those measurements at the same locations at 7-month intervals. Measurement data compiled from the seven locations with the highest deposition were combined with data from aerial surveys since May 1986 of ground deposition of 137Cs, high-resolution gamma spectrometry performed at four locations in May 1986, and measurements from fixed continuous air gamma rate monitoring stations from 28 April to 15 May 1986. Based on these datasets, a model of the time pattern of the external dose rate in terms of ambient dose equivalent rate from the Chernobyl fallout was developed. The decrease in the ambient dose equivalent rate could, on average, be described by a four-component exponential decay function with effective half-times of 6.8 ± 0.3 d, 104 ± 26 d, 1.0 ± 0.02 y and 5.5 ± 0.09 y, respectively. The predominant contributions to the external dose rate in the first month were from short-lived fission products superseded by 134Cs and then 137Cs. Integrated over 70 y and using extrapolation of the curve fits, our model predicts that 137Cs contributes about 60% and 134Cs contributes about 30% of the external effective dose at these seven locations. The projected time-integrated 70 y external effective dose to an unshielded person from all nuclides per unit total activity deposition of 137Cs is estimated to be 0.29 ± 0.0.08 mSv/(kBq m-2). These results are in agreement with those found in Chernobyl contaminated Russian forest areas, and emphasize the usefulness of maintaining a long-term and regular measurement program in contaminated areas.
|
|
| 46. |
- Kock, Peder, et al.
(författare)
-
On background radiation gradients - the use of airborne surveys when searching for orphan sources using mobile gamma-ray spectrometry
- 2014
-
Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 128, s. 84-90
-
Tidskriftsartikel (refereegranskat)abstract
- Systematic background radiation variations can lead to both false positives and failures to detect an orphan source when searching using car-borne mobile gamma-ray spectrometry. The stochastic variation at each point is well described by Poisson statistics, but when moving in a background radiation gradient the mean count rate will continually change, leading to inaccurate background estimations. Airborne gamma spectrometry (AGS) surveys conducted on the national level, usually in connection to mineral exploration, exist in many countries. These data hold information about the background radiation gradients which could be used at the ground level. This article describes a method that aims to incorporate the systematic as well as stochastic variations of the background radiation. We introduce a weighted moving average where the weights are calculated from existing AGS data, supplied by the Geological Survey of Sweden. To test the method we chose an area with strong background gradients, especially in the thorium component. Within the area we identified two roads which pass through the high-variability locations. The proposed method is compared with an unweighted moving average. The results show that the weighting reduces the excess false positives in the positive background gradients without introducing an excess of failures to detect a source during passage in negative gradients. (C) 2013 Elsevier Ltd. All rights reserved.
|
|
| 47. |
|
|
| 48. |
- Magnusson, Åsa, et al.
(författare)
-
Carbon-14 levels in the vicinity of the Lithuanian nuclear power plant Ignalina
- 2007
-
Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 259:1, s. 530-535
-
Tidskriftsartikel (refereegranskat)abstract
- Carbon-14 levels in the vicinity of the Lithuanian nuclear power plant Ignalina have been investigated. During 2001-2004, approximately 70 samples were collected and analysed using accelerator mass spectrometry. The study included samples of leaves, grass, moss, soil and aquatic plants, covering a distance up to 32 km from the power plant. The highest C-14 specific activities were found in soil samples from moss-covered sites close to the power plant, probably indicating the release of particulate material. The results are compared with those from studies around other types of reactors also investigated within the project. (c) 2007 Elsevier B.V. All rights reserved.
|
|
| 49. |
- Magnusson, Åsa, et al.
(författare)
-
Levels of C-14 in the terrestrial environment in the vicinity of two European nuclear power plants
- 2004
-
Ingår i: Radiocarbon. - 0033-8222. ; 46:2, s. 863-868
-
Tidskriftsartikel (refereegranskat)abstract
- Radiocarbon is produced in all types of nuclear reactors. Most of the C-14 released into the environment is in the form of gaseous emissions. Recent data on the C-14 concentration found in terrestrial samples taken in the vicinity of nuclear power plants in Romania and Lithuania are presented. We found increased C-14 levels in the surroundings of both power plants. At the Romanian power plant Cernavoda, we found excess levels of C-14 in grass within a distance of about 1000 in, the highest C-14 specific activity being 311 Bq/kg C (approximately 28% above the contemporary C-14 background) found at a distance of 200 in from the point of release (nearest sampling location). At the Lithuanian power plant Ignalina, samples of willow, pine, and spruce showed a C-14 excess of similar magnitude, while significantly higher values were found in moss samples. The samples were analyzed at the accelerator mass spectrometry facility in Lund, Sweden.
|
|
| 50. |
- Majgier, Renata, et al.
(författare)
-
OSL PROPERTIES IN VARIOUS FORMS OF KCl AND NaCl SAMPLES AFTER EXPOSURE TO IONIZING RADIATION
- 2019
-
Ingår i: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 184:1, s. 90-97
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this work was to investigate the optically-stimulated luminescence (OSL) properties of potassium chloride (KCl) and its potential use in radiation dosimetry. The optimal condition for OSL readout with blue light stimulation were designated using a commercially available Risø TL/OSL reader. KCl was studied in three sample forms: crystals, powder and pellets. The following OSL characteristics were determined: signal reproducibility, OSL measurement-induced sensitivity changes, temperature dependence of OSL and signal stability over time. The results show a high reproducibility of KCl samples and strong sensitivity changes, which can be corrected for by using a test-dose. The long-term OSL studies confirmed the occurrence of both inverse fading and fading phenomena in KCl. In addition, a comparison with corresponding measurements using sodium chloride (NaCl) were carried out. Although it was confirmed that NaCl is more suitable for dosimetry, there might be benefits of combining NaCl with KCl for more accurate absorbed dose determinations.
|
|
