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De Meutter P, Hoffman I, Delcloo AW. A baseline for source localisation using the inverse modelling tool FREAR. J Environ Radioact 2024; 273:107372. [PMID: 38262302 DOI: 10.1016/j.jenvrad.2024.107372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 12/29/2023] [Accepted: 01/10/2024] [Indexed: 01/25/2024]
Abstract
A global network of monitoring stations is set up that can measure tiny concentrations of airborne radioactivity as part of the verification regime of the Comprehensive Nuclear-Test-Ban Treaty. If Treaty-relevant detections are made, inverse atmospheric transport modelling is one of the methods that can be used to determine the source of the radioactivity. In order to facilitate the testing of novel developments in inverse modelling, two sets of test cases are constructed using real-world 133Xe detections associated with routine releases from a medical isotope production facility. One set consists of 24 cases with 5 days of observations in each case, and another set consists of 8 cases with 15 days of observations in each case. A series of inverse modelling techniques and several sensitivity experiments are applied to determine the (known) location of the medical isotope production facility. Metrics are proposed to quantify the quality of the source localisation. Finally, it is illustrated how the sets of test cases can be used to test novel developments in inverse modelling algorithms.
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2
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Maurer C, Galmarini S, Solazzo E, Kuśmierczyk-Michulec J, Baré J, Kalinowski M, Schoeppner M, Bourgouin P, Crawford A, Stein A, Chai T, Ngan F, Malo A, Seibert P, Axelsson A, Ringbom A, Britton R, Davies A, Goodwin M, Eslinger PW, Bowyer TW, Glascoe LG, Lucas DD, Cicchi S, Vogt P, Kijima Y, Furuno A, Long PK, Orr B, Wain A, Park K, Suh KS, Quérel A, Saunier O, Quélo D. Third international challenge to model the medium- to long-range transport of radioxenon to four Comprehensive Nuclear-Test-Ban Treaty monitoring stations. J Environ Radioact 2022; 255:106968. [PMID: 36148707 DOI: 10.1016/j.jenvrad.2022.106968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 07/08/2022] [Accepted: 07/15/2022] [Indexed: 06/16/2023]
Abstract
In 2015 and 2016, atmospheric transport modeling challenges were conducted in the context of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) verification, however, with a more limited scope with respect to emission inventories, simulation period and number of relevant samples (i.e., those above the Minimum Detectable Concentration (MDC)) involved. Therefore, a more comprehensive atmospheric transport modeling challenge was organized in 2019. Stack release data of Xe-133 were provided by the Institut National des Radioéléments/IRE (Belgium) and the Canadian Nuclear Laboratories/CNL (Canada) and accounted for in the simulations over a three (mandatory) or six (optional) months period. Best estimate emissions of additional facilities (radiopharmaceutical production and nuclear research facilities, commercial reactors or relevant research reactors) of the Northern Hemisphere were included as well. Model results were compared with observed atmospheric activity concentrations at four International Monitoring System (IMS) stations located in Europe and North America with overall considerable influence of IRE and/or CNL emissions for evaluation of the participants' runs. Participants were prompted to work with controlled and harmonized model set-ups to make runs more comparable, but also to increase diversity. It was found that using the stack emissions of IRE and CNL with daily resolution does not lead to better results than disaggregating annual emissions of these two facilities taken from the literature if an overall score for all stations covering all valid observed samples is considered. A moderate benefit of roughly 10% is visible in statistical scores for samples influenced by IRE and/or CNL to at least 50% and there can be considerable benefit for individual samples. Effects of transport errors, not properly characterized remaining emitters and long IMS sampling times (12-24 h) undoubtedly are in contrast to and reduce the benefit of high-quality IRE and CNL stack data. Complementary best estimates for remaining emitters push the scores up by 18% compared to just considering IRE and CNL emissions alone. Despite the efforts undertaken the full multi-model ensemble built is highly redundant. An ensemble based on a few arbitrary runs is sufficient to model the Xe-133 background at the stations investigated. The effective ensemble size is below five. An optimized ensemble at each station has on average slightly higher skill compared to the full ensemble. However, the improvement (maximum of 20% and minimum of 3% in RMSE) in skill is likely being too small for being exploited for an independent period.
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Affiliation(s)
- C Maurer
- Zentralanstalt für Meteorologie und Geodynamik (ZAMG), Vienna, Austria.
| | - S Galmarini
- European Commission - Joint Research Center (JRC), Ispra VA, Italy
| | - E Solazzo
- European Commission - Joint Research Center (JRC), Ispra VA, Italy
| | | | - J Baré
- Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), Vienna, Austria
| | - M Kalinowski
- Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), Vienna, Austria
| | - M Schoeppner
- Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), Vienna, Austria
| | - P Bourgouin
- Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), Vienna, Austria
| | - A Crawford
- National Oceanic and Atmospheric Administration Air Resources Laboratory (NOAA-ARL), College Park, MD, USA
| | - A Stein
- National Oceanic and Atmospheric Administration Air Resources Laboratory (NOAA-ARL), College Park, MD, USA
| | - T Chai
- National Oceanic and Atmospheric Administration Air Resources Laboratory (NOAA-ARL), College Park, MD, USA
| | - F Ngan
- National Oceanic and Atmospheric Administration Air Resources Laboratory (NOAA-ARL), College Park, MD, USA
| | - A Malo
- Environment and Climate Change Canada (ECCC), Meteorological Service of Canada, Canadian Meteorological Centre (CMC), Environmental Emergency Response Section, RSMC Montréal, Dorval, Québec, Canada
| | - P Seibert
- University of Natural Resources and Life Sciences (BOKU), Institute of Meteorology and Climatology, Vienna, Austria
| | - A Axelsson
- Swedish Defence Research Agency (FOI), Stockholm, Sweden
| | - A Ringbom
- Swedish Defence Research Agency (FOI), Stockholm, Sweden
| | - R Britton
- Atomic Weapons Establishment/United Kingdom-National Data Center (AWE/UK-NDC), Aldermaston, Reading, United Kingdom
| | - A Davies
- Atomic Weapons Establishment/United Kingdom-National Data Center (AWE/UK-NDC), Aldermaston, Reading, United Kingdom
| | - M Goodwin
- Atomic Weapons Establishment/United Kingdom-National Data Center (AWE/UK-NDC), Aldermaston, Reading, United Kingdom
| | - P W Eslinger
- Pacific Northwest National Laboratory (PNNL), Richland, WA, USA
| | - T W Bowyer
- Pacific Northwest National Laboratory (PNNL), Richland, WA, USA
| | - L G Glascoe
- National Atmospheric Release Advisory Center (NARAC) at the Lawrence Livermore National Laboratory (LLNL), Livermore, CA, USA
| | - D D Lucas
- National Atmospheric Release Advisory Center (NARAC) at the Lawrence Livermore National Laboratory (LLNL), Livermore, CA, USA
| | - S Cicchi
- National Atmospheric Release Advisory Center (NARAC) at the Lawrence Livermore National Laboratory (LLNL), Livermore, CA, USA
| | - P Vogt
- National Atmospheric Release Advisory Center (NARAC) at the Lawrence Livermore National Laboratory (LLNL), Livermore, CA, USA
| | - Y Kijima
- Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki, Japan
| | - A Furuno
- Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki, Japan
| | - P K Long
- Vietnam Atomic Energy Institute (VINATOM), Hanoi, Vietnam
| | - B Orr
- Australian Radiation Protection and Nuclear Safety Agency (ARPANSA), Yallambie/Miranda, Australia
| | - A Wain
- Bureau of Meteorology (BOM), Melbourne, Australia
| | - K Park
- Korea Atomic Energy Research Institute (KAERI), Daejeon, Republic of Korea
| | - K-S Suh
- Korea Atomic Energy Research Institute (KAERI), Daejeon, Republic of Korea
| | - A Quérel
- French Institute for Radiation Protection and Nuclear Safety (IRSN), Fontenay-aux-Roses, France
| | - O Saunier
- French Institute for Radiation Protection and Nuclear Safety (IRSN), Fontenay-aux-Roses, France
| | - D Quélo
- French Institute for Radiation Protection and Nuclear Safety (IRSN), Fontenay-aux-Roses, France
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3
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De Meutter P, Delcloo AW. Uncertainty quantification of atmospheric transport and dispersion modelling using ensembles for CTBT verification applications. J Environ Radioact 2022; 250:106918. [PMID: 35653875 DOI: 10.1016/j.jenvrad.2022.106918] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 04/22/2022] [Accepted: 05/16/2022] [Indexed: 06/15/2023]
Abstract
Airborne concentrations of specific radioactive xenon isotopes (referred to as "radioxenon") are monitored globally as part of the verification regime of the Comprehensive Nuclear-Test-Ban Treaty, as these could be the signatures of a nuclear explosion. However, civilian nuclear facilities emit a regulated amount of radioxenon that can interfere with the very sensitive monitoring network. One approach to deal with this civilian background of radioxenon for Treaty verification purposes, is to explicitly simulate the expected radioxenon concentration from civilian sources at monitoring stations using atmospheric transport modelling. However, atmospheric transport modelling is prone to uncertainty, and the absence of an uncertainty quantification can limit its use for detection screening. In this paper, several ensembles are assessed that could provide an atmospheric transport modelling uncertainty quantification. These ensembles are validated with radioxenon observations, and recommendations are given for atmospheric transport modelling uncertainty quantification. Finally, the added value of an ensemble for detection screening is illustrated.
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Affiliation(s)
- Pieter De Meutter
- Belgian Nuclear Research Centre (SCK CEN) Boertang 200, 2400, Mol, Belgium; Royal Meteorological Institute of Belgium, Ringlaan 3, 1180, Brussels, Belgium.
| | - Andy W Delcloo
- Royal Meteorological Institute of Belgium, Ringlaan 3, 1180, Brussels, Belgium; Department of Physics and Astronomy, Ghent University, Krijgslaan 281/S9, B-9000, Ghent, Belgium
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4
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Villarreal RE, Arazi A, Fernández Niello JO. Correlation between the latitudinal profile of the 7Be air concentration and the Hadley cell extent in the Southern Hemisphere. J Environ Radioact 2022; 244-245:106760. [PMID: 35093613 DOI: 10.1016/j.jenvrad.2021.106760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 10/19/2021] [Accepted: 10/23/2021] [Indexed: 06/14/2023]
Abstract
The cosmogenic radionuclide 7Be is one of the best tracers for aerosol transport since its half-life of 53 days is in the time scale of many atmospheric circulation phenomena. In this work, we analyze a 12-years-long daily time-series for the airborne 7Be concentration for nine air filtering stations in the Southern Hemisphere or close to it. The observed latitudinal distribution of 7Be concentration, with its maximum at the southern subtropical high-pressure belt, is similar to the one in the Northern Hemisphere. A good time correlation was found between the 7°-shift of the 7Be concentration latitudinal distribution and the seasonal displacement of the extent of the Hadley cell. This is consistent with tropopause folding events, mostly occurring in spring, being the main contribution for the injection of stratospheric 7Be into the descending branch of the Hadley cell.
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Affiliation(s)
- R E Villarreal
- Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, Provisional Technical Secretariat, Vienna International Centre, P.O. Box 1200, A-1400, Vienna, Austria.
| | - A Arazi
- Laboratorio TANDAR, Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499, B1650KNA, San Martín, Argentina; CONICET, Godoy Cruz 2290, C1425FQB, Buenos Aires, Argentina
| | - J O Fernández Niello
- Laboratorio TANDAR, Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499, B1650KNA, San Martín, Argentina; CONICET, Godoy Cruz 2290, C1425FQB, Buenos Aires, Argentina; Instituto de Investigación e Ingeniería Ambiental, Universidad Nacional de San Martín, B1650BWA, San Martín, Argentina
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Abdollahnejad H, Rezaei Ochbelagh D, Azadi M. An investigation on the 133Xe global network coverage for the International Monitoring System of the Comprehensive Nuclear-Test-Ban Treaty. J Environ Radioact 2021; 237:106701. [PMID: 34303213 DOI: 10.1016/j.jenvrad.2021.106701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 07/07/2021] [Accepted: 07/08/2021] [Indexed: 06/13/2023]
Abstract
The radionuclides part of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) global network of International Monitoring System (IMS) is based on the measurement of particles and radioactive noble gases. Forty radionuclide stations are going to be equipped with radioxenon measurement components to monitor the nuclear explosion signatures around the world. Global coverage of the noble gas IMS stations has been investigated using atmospheric transport modelling. Two years of worldwide release for a hypothetical 1-kt underground nuclear explosion and detection of 133Xe in the IMS radioxenon station locations are considered. The present and completed status were supposed as two different scenarios to estimate the daily coverage of the network. The calculated quantities were evaluated corresponding to the whole latitude/longitude grid in image-base and numerical patterns. Although the fluctuation of daily coverage is varying in time, the cumulative minimum amounts were indicated that North America has stable high coverage in the present arrangement. Moreover, after the completion of the network, this aspect will be expanded to the middle part of the Northern Hemisphere as well as the west region of the Southern Hemisphere. Finally exploring the cumulative maximum daily coverage is denoted that adding the non-operational stations to the current network has a great influence on the 20 S - 90 N latitudes to 0-180 W longitudes and about 50% effect on the network coverage (NC) of the north of Europe, South Atlantic, and Oceania. However, it has almost no impact on the values of the limited area around the middle east part of the Pacific Ocean.
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Affiliation(s)
- Hamed Abdollahnejad
- Department of Energy Engineering & Physics, AmirKabir University of Technology (Tehran Polytechnic), Tehran, Iran.
| | - Dariush Rezaei Ochbelagh
- Department of Energy Engineering & Physics, AmirKabir University of Technology (Tehran Polytechnic), Tehran, Iran.
| | - Majid Azadi
- Atmospheric Science and Meteorological Research Center, Tehran, Iran.
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Maurer C, Arias DA, Brioude J, Haselsteiner M, Weidle F, Haimberger L, Skomorowski P, Bourgouin P. Evaluating the added value of multi-input atmospheric transport ensemble modeling for applications of the Comprehensive Nuclear Test-Ban Treaty organization ( CTBTO). J Environ Radioact 2021; 237:106649. [PMID: 34118614 DOI: 10.1016/j.jenvrad.2021.106649] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 05/05/2021] [Accepted: 05/10/2021] [Indexed: 06/12/2023]
Abstract
The Comprehensive Nuclear Test-Ban Treaty Organization (CTBTO) runs to date operationally an atmospheric transport modeling chain in backward mode based on operational deterministic European Centre for Medium-Range Weather Forecasts-Integrated Forecasting System (ECMWF-IFS) and on National Centers for Environmental Prediction-Global Forecast System (NCEP-GFS) input data. Meanwhile, ensemble dispersion modeling is becoming more and more widespread due to the ever increasing computational power and storage capacities. The potential benefit of this approach for current and possible future CTBTO applications was investigated using data from the ECMWF-Ensemble Prediction System (EPS). Five different test cases - among which are the ETEX-I experiment and the Fukushima accident - were run in backward or forward mode and - in the light of a future operational application - special emphasis was put on the performance of an arbitrarily selected 10- versus the full 51-member ensemble. For those test cases run in backward mode and based on a puff release it became evident that Possible Source Regions (PSRs) can be meaningfully reduced in size compared to results based solely on the deterministic run by applying minimum and probability of exceedance ensemble metrics. It was further demonstrated that a given puff release of 4E10 Bq of Se-75 can be reproduced within the meteorological uncertainty range [1.9E9 Bq,1.7E13 Bq] including a probability for not exceeding an assumed upper limit source term using simple scaling of a measurement with the corresponding ensemble metrics of backward fields. For the test cases run in forward mode it was found that the control run as well as 10- and 51-member medians all exhibit similar performance in time series evaluation. Maximum rank difference adds up to less than 10% with reference to possible rank values [0,4]. The maximum difference in the Brier score for both ensembles is less than 3%. The main added value of the ensemble lies in producing meteorologically induced concentration uncertainties and thus explaining observed measurements at specific sites. Depending on the specific test case and on the ensemble size between 27 and 74% of samples all lie within concentration ranges derived from the different meteorological fields used. In the future uncertainty information per sample could be used in a full source term inversion to account for the meteorological uncertainty in a proper way. It can be concluded that a 10-member meteorological ensemble is good enough to already benefit from useful ensemble properties. Meteorological uncertainty to a large degree is covered by the 10-member subset because forecast uncertainty is largely suppressed due to concatenating analyses and short term forecasts, as required in the operational CTBTO procedure, on which this study focuses. Besides, members from different analyses times are on average unrelated. It was recommended to Working Group B of CTBTO to implement the ensemble system software in the near future.
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Affiliation(s)
- C Maurer
- Zentralanstalt für Meteorologie und Geodynamik, Hohe Warte 38, 1190, Vienna, Austria.
| | - D Arnold Arias
- Zentralanstalt für Meteorologie und Geodynamik, Hohe Warte 38, 1190, Vienna, Austria; Arnold Scientific Consulting, Libertat 46, 08243, Manresa, Spain
| | - J Brioude
- Atmosphere and Cyclone Lab (LACy - UMR8105), University de La Réunion, Avenue René Cassin 15, 97744, Saint-Denis, La Réunion, France
| | - M Haselsteiner
- Zentralanstalt für Meteorologie und Geodynamik, Hohe Warte 38, 1190, Vienna, Austria
| | - F Weidle
- Zentralanstalt für Meteorologie und Geodynamik, Hohe Warte 38, 1190, Vienna, Austria
| | - L Haimberger
- Institut for Meteorology and Geophysics, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
| | - P Skomorowski
- Zentralanstalt für Meteorologie und Geodynamik, Hohe Warte 38, 1190, Vienna, Austria
| | - P Bourgouin
- Comprehensive Nuclear Test-Ban Treaty Organization, Wagramerstrasse 5, 1400, Vienna, Austria
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7
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Fritz BG, Alexander T, Bowyer T, Hayes J, Mace E, Woods V. Comparison of near-background concentrations of Argon-37 and Xenon-133 in the atmosphere. J Environ Radioact 2021; 233:106590. [PMID: 33798811 DOI: 10.1016/j.jenvrad.2021.106590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 03/09/2021] [Accepted: 03/12/2021] [Indexed: 06/12/2023]
Abstract
Radioisotopes of the noble gases xenon and argon can be important indicators of underground nuclear explosions. The Comprehensive Nuclear-Test-Ban Treaty (CTBT) includes monitoring capabilities to identify potential nuclear explosions conducted in violation of the CTBT. This monitoring currently focuses on measurement of the xenon isotopes 131mXe, 133Xe, 133mXe, and 135Xe. However, it is predicted that within 100 days of an underground nuclear explosion (UNE) 37Ar would be released to the atmosphere at higher concentrations than xenon and with a higher signal to background ratio, depending on the radioxenon background levels. Therefore, inclusion of 37Ar measurement capabilities at atmospheric International Monitoring System (IMS) stations may represent an improvement in the capability to detect a nuclear explosion. At an IMS station location, an understanding of the expected range of background 37Ar activity concentrations is critical to determining what levels would constitute an elevated concentration. This work describes our analysis of atmospheric samples for 37Ar to evaluate the range of background concentrations. Samples were collected at multiple locations withing the United States, with approximately half coming from a sampler co-located with an IMS xenon monitoring station (RN75). The range of 37Ar concentrations measured in atmospheric air samples was relatively narrow; for samples considered detectable, the minimum and maximum measured concentrations were 0.56 and 2.3 mBq/m3, respectively. Comparison of 37Ar and 133Xe concentrations measured at the IMS station indicated some correlation between the measured concentrations. The results presented here demonstrate the capability to detect background concentrations of 37Ar in atmospheric air and provide a basis for potential implementation of 37Ar monitoring at IMS stations.
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Affiliation(s)
- B G Fritz
- Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99454, USA.
| | - ThomasR Alexander
- Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99454, USA
| | - TheodoreW Bowyer
- Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99454, USA
| | - JamesC Hayes
- Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99454, USA
| | - EmilyK Mace
- Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99454, USA
| | - VincentT Woods
- Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99454, USA
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Topin S, Gross P, Achim P, Generoso S, Cagniant A, Delaune O, Morin M, Philippe T, Fontaine JP, Moulin C, Douysset G, Le Petit G. 6 months of radioxenon detection in western Europe with the SPALAX-New generation system - Part1: Metrological capabilities. J Environ Radioact 2020; 225:106442. [PMID: 33080418 DOI: 10.1016/j.jenvrad.2020.106442] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/28/2020] [Accepted: 09/29/2020] [Indexed: 06/11/2023]
Abstract
The SPALAX-NG is a new-generation system that is designed to detect radioactive xenon at trace levels in the atmosphere following a nuclear explosion or civilian source release. This new system formed part of a validation program led by the Provisional Technical Secretary of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) Organization. In this study, the first SPALAX-NG unit was tested for six months between October 2018 and April 2019 at the CEA/DIF premises near Paris, France. This test period provided an outstanding opportunity to illustrate the high level of detectability and reliability of the system. The data availability obtained over this period was approximately 99%, which was well above the CTBT Data Availability criteria of 95%. The data reliability was demonstrated by a comparison with a collocated SPALAX-1 unit (former version of SPALAX) and by re-measuring several samples at the CTBT-certified French laboratory FRL08. The high sensitivity to the detection of the four relevant radioxenon isotopes was fully demonstrated and enabled the recording of a major dataset for western Europe. A large set of isotopic ratios was measured, which enabled the discrimination criteria between civilian sources and nuclear test signatures to be refined.
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Park H. Rare observation of atmospheric 65Zn, 134Cs and 137Cs with possible relation to the 12 February 2013 test announced by North Korea. J Environ Radioact 2020; 217:106220. [PMID: 32217252 DOI: 10.1016/j.jenvrad.2020.106220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 02/24/2020] [Accepted: 02/24/2020] [Indexed: 06/10/2023]
Abstract
Abnormal particulate radionuclides (65Zn, 134Cs and 137Cs) were detected at the CTBTO RN58 station which is located near North Korea between 12 and March 14, 2016. Detection ratio for caesium (134Cs/137Cs) shows that the product origin was nuclear explosion and dilution factors at RN58, released from DPRK test site, show clear correlation with radioactivity concentration of two samples. The detected radionuclides may be originated from the third nuclear test, February 2013. Half-life, radionuclides fractionation, MDC, and device design are attributed to no detection of other nuclides. Most of radionuclides have been decayed away and relatively long half-life nuclides might be in the third test site but they were displaced deep inside the area by fractionation during the explosion. Considering 65Zn activity ratio to 137Cs which is higher than historical ratios at Brunswick in 1968, there is a possibility that the third DPRK nuclear test was a "salted" nuclear bomb test using zinc as jacket instead of fissionable 238U around the secondary stage fusion fuel.
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Affiliation(s)
- Hongmo Park
- Korea Institute of Nuclear Safety, 62 Gwahak-ro, Yuseong-gu, Daejeon, 34142, Republic of Korea.
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Cruz PTF, Bonga AC, Dela Sada CL, Olivares JU, Dela Cruz FM, Palad LJH, Jesuitas AJ, Cabatbat EC, Omandam VJ, Garcia TY, Feliciano CP. Assessment of temporal variations of natural radionuclides Beryllium-7 and Lead-212 in surface air in Tanay, Philippines. J Environ Radioact 2019; 208-209:105989. [PMID: 31207564 DOI: 10.1016/j.jenvrad.2019.105989] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 05/27/2019] [Accepted: 06/01/2019] [Indexed: 06/09/2023]
Abstract
Detection of radionuclides in surface air allows researchers to gain further insight on the behavior of radionuclides that may affect human radiation exposure especially in the event of a nuclear emergency. In this study, activity concentrations of naturally-occurring radionuclides Beryllium-7 (7Be) and Lead-212 (212Pb) in surface air and meteorological data collected in Tanay, Philippines from January 2012 to December 2017 were evaluated to determine the impact of atmospheric conditions and processes to airborne radioactivity. Surface air concentrations of 7Be and 212Pb were found to range from 0.00779 ± 0.00188 to 11.2 ± 0.116 mBq/m3 and from 1.371 ± 0.036 to 106.6 ± 1.075 mBq/m3, respectively. 7Be and 212Pb show distinct annual trends, suggesting that atmospheric conditions affect both radionuclides differently and independently. 7Be shows two peak concentrations annually, with the first peak occurring between January to April and the second lower peak occurring between October and November. 212Pb, on the other hand, shows annual peak concentrations occurring between April and June. Ambient temperature showed strong positive correlation with 212Pb concentration in surface air and a weak negative correlation with 7Be; relative humidity and precipitation showed varying degrees of negative correlation with radionuclide concentrations in surface air. Source locations for the unusually high 212Pb activity concentrations detected on 11-13 May 2013 and 19-31 May 2015 determined using WEB-GRAPE and HYSPLIT atmospheric transport models are presented as a case study. The data and findings of this study shall serve as basis for further studies on local and regional atmospheric transport and radiological impact assessment for the implementation of an effective nuclear and radiological emergency preparedness and response system in the country.
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Affiliation(s)
- Paolo Tristan F Cruz
- Health Physics Research Section, Philippine Nuclear Research Institute, Department of Science and Technology (DOST-PNRI), Commonwealth Avenue, Diliman, Quezon City, Philippines.
| | - Antonio C Bonga
- Health Physics Research Section, Philippine Nuclear Research Institute, Department of Science and Technology (DOST-PNRI), Commonwealth Avenue, Diliman, Quezon City, Philippines
| | - Christian L Dela Sada
- Health Physics Research Section, Philippine Nuclear Research Institute, Department of Science and Technology (DOST-PNRI), Commonwealth Avenue, Diliman, Quezon City, Philippines
| | - Juanario U Olivares
- Health Physics Research Section, Philippine Nuclear Research Institute, Department of Science and Technology (DOST-PNRI), Commonwealth Avenue, Diliman, Quezon City, Philippines
| | - Fe M Dela Cruz
- Health Physics Research Section, Philippine Nuclear Research Institute, Department of Science and Technology (DOST-PNRI), Commonwealth Avenue, Diliman, Quezon City, Philippines
| | - Lorna Jean H Palad
- Health Physics Research Section, Philippine Nuclear Research Institute, Department of Science and Technology (DOST-PNRI), Commonwealth Avenue, Diliman, Quezon City, Philippines
| | - Alejandro J Jesuitas
- Synoptic and Upper Air Station, Philippine Atmospheric, Geophysical, and Astronomical Services Administration, Department of Science and Technology (DOST-PAGASA), Sitio Mayagay, Sampaloc, Tanay, Rizal, Philippines
| | - Edwin C Cabatbat
- Synoptic and Upper Air Station, Philippine Atmospheric, Geophysical, and Astronomical Services Administration, Department of Science and Technology (DOST-PAGASA), Sitio Mayagay, Sampaloc, Tanay, Rizal, Philippines
| | - Vanessa J Omandam
- Health Physics Research Section, Philippine Nuclear Research Institute, Department of Science and Technology (DOST-PNRI), Commonwealth Avenue, Diliman, Quezon City, Philippines
| | - Teofilo Y Garcia
- Health Physics Research Section, Philippine Nuclear Research Institute, Department of Science and Technology (DOST-PNRI), Commonwealth Avenue, Diliman, Quezon City, Philippines
| | - Chitho P Feliciano
- Health Physics Research Section, Philippine Nuclear Research Institute, Department of Science and Technology (DOST-PNRI), Commonwealth Avenue, Diliman, Quezon City, Philippines
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11
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Gadey HR, Farsoni AT, Czyz SA, McGee KD. A stilbene - CdZnTe based radioxenon detection system. J Environ Radioact 2019; 204:117-124. [PMID: 31029985 DOI: 10.1016/j.jenvrad.2019.03.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 03/27/2019] [Accepted: 03/27/2019] [Indexed: 06/09/2023]
Abstract
Atmospheric monitoring of radioxenon is one of the most widely used methods by the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) to detect elevated levels of 131mXe, 133/133mXe, and 135Xe. The ratios of these radionuclides help discriminate between peaceful use of nuclear technology and nuclear weapon explosions. Radioxenon detection systems often use plastic scintillators in the capacity of an electron detector and a gas cell, plastic gas cells are responsible for introducing high memory effect in these systems. This work presents the design of a new detection system for radioxenon monitoring that utilizes silicon photomultipliers, a stilbene gas cell, and a CdZnTe detector. This detector was evaluated using xenon radioisotope samples produced in the TRIGA reactor at Oregon State University. A 48-h background was collected and calculations of the Minimum Detectable Concentration (MDC) were carried out using the Region of Interest (ROI) approach. An MDC of less than 1 mBq/m3 was obtained for 131mXe, 133Xe, and 133mXe in accordance with the sensitivity limits set by the CTBTO and performs respectably when compared to state-of-the-art radioxenon detection systems. Using 131mXe, this study indicates that the stilbene gas cell exhibits a memory effect of 0.045 ± 0.017%, this is almost a two-order magnitude improvement compared to plastic scintillators. The primary purpose of this work is to explore the use of new stilbene detection media for radioxenon application and addressing the problem of memory effect.
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Affiliation(s)
- Harish R Gadey
- School of Nuclear Science and Engineering, Oregon State University, 3451 SW Jefferson Way, Corvallis, OR, 97331, USA.
| | - Abi T Farsoni
- School of Nuclear Science and Engineering, Oregon State University, 3451 SW Jefferson Way, Corvallis, OR, 97331, USA
| | - Steven A Czyz
- School of Nuclear Science and Engineering, Oregon State University, 3451 SW Jefferson Way, Corvallis, OR, 97331, USA
| | - Kacey D McGee
- School of Nuclear Science and Engineering, Oregon State University, 3451 SW Jefferson Way, Corvallis, OR, 97331, USA
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12
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Cagniant A, Delaune O, Réglat M, Douysset G, Gross P, Le Petit G. Ground surface ultralow background spectrometer: Active shielding improvements and coincidence measurements for the Gamma 3 spectrometer. Appl Radiat Isot 2017; 126:197-200. [PMID: 28187930 DOI: 10.1016/j.apradiso.2017.01.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 01/05/2017] [Accepted: 01/25/2017] [Indexed: 11/28/2022]
Abstract
The ultralow background versatile spectrometer GAMMA3 has been optimized with the following shielding improvements: (i) optimized nitrogen injection flux of 300Lh-1, and (ii) cosmic veto configuration with 9 scintillating plates. These improvements allow a reduction of 39% of the normalized integral background count rate down to 2.7±0.2min-1kgGe-1 (40-2500keV energy range). Minimum Detectable Activities when performing direct γ-ray spectrometry or γ-γ coincidence spectrometry are compared.
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Affiliation(s)
| | - O Delaune
- CEA, DAM, DIF, F-91297 Arpajon, France
| | - M Réglat
- CEA, DAM, DIF, F-91297 Arpajon, France
| | | | - P Gross
- CEA, DAM, DIF, F-91297 Arpajon, France
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13
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Zhou C, Zhou G, Feng S, Huang D, Zhao X, Wieslander JSE, Khrustalev K, Yu X, Cheng Z, Wu R, Zou R. Development of a mobile radioxenon processing system for on-site inspections and the deployment in IFE14. J Environ Radioact 2016; 162-163:310-318. [PMID: 27323211 DOI: 10.1016/j.jenvrad.2016.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 05/08/2016] [Accepted: 06/03/2016] [Indexed: 06/06/2023]
Abstract
A mobile radioxenon gas processing system (XESPM-III) was developed for on-site inspections-targeting deployment in the Integrated Field Exercise in Jordan 2014 (IFE14)-in order to monitor radioxenon isotopes (131m,133,133m,135Xe) from the subsoil and atmosphere. XESPM-III is composed of primarily three units, the sampling unit, the purification unit and finally the quantification unit. The function of the sampling unit is to pre-enrich xenon by removal of impurities in the gas sample, while the purification unit further purifies, separates impurities and prepares a small-volume sample with relatively high concentration of xenon gas-both stable and radioactive xenon (if present). The quantification unit quantifies the stable xenon which provides information of the gas recovery (yield) of the gas sampling and purification process. In one cycle (7.5 h) XESPM-III can process either two 4 m3 volume samples or two pairs 2 m3 samples each; 24 h maximum throughput is thus twelve 2 m3 samples or six 4 m3 samples; final purified gas sample volume is approx. 7 cm3 (Xe + N2 used as carrier gas); gas recovery (yield) is >70%; radon removal coefficient is 10-6; cross contamination between subsequent samples is <1%; Its flexible design, that does not include a spectrometry system, allows it to be used with various spectrometric systems (HPGe, beta-gamma coincidence) for the final measurement of the radioactive xenon concentrations in the sample. During the field deployment of the XESPM-III in IFE14 it was able to measure 133Xe in the range of 0.18-0.54 Bq/m3 in spiked subsoil gas.
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Affiliation(s)
- Chongyang Zhou
- Northwest Institute of Nuclear Technology, P. O. Box 69-27, Xi'an, 710024 China.
| | - Guoqing Zhou
- Northwest Institute of Nuclear Technology, P. O. Box 69-27, Xi'an, 710024 China
| | - Shujuan Feng
- Northwest Institute of Nuclear Technology, P. O. Box 69-27, Xi'an, 710024 China
| | - Dingwei Huang
- Northwest Institute of Nuclear Technology, P. O. Box 69-27, Xi'an, 710024 China
| | - Xinhua Zhao
- Northwest Institute of Nuclear Technology, P. O. Box 69-27, Xi'an, 710024 China
| | - J S Elisabeth Wieslander
- Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, Provisional Technical Secretariat, P.O. Box 1200, A-1400, Vienna, Austria
| | - Kirill Khrustalev
- Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, Provisional Technical Secretariat, P.O. Box 1200, A-1400, Vienna, Austria
| | - Xiaolong Yu
- Northwest Institute of Nuclear Technology, P. O. Box 69-27, Xi'an, 710024 China
| | - Ziwei Cheng
- Northwest Institute of Nuclear Technology, P. O. Box 69-27, Xi'an, 710024 China
| | - Rui Wu
- Northwest Institute of Nuclear Technology, P. O. Box 69-27, Xi'an, 710024 China
| | - Ronghu Zou
- Northwest Institute of Nuclear Technology, P. O. Box 69-27, Xi'an, 710024 China
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14
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Eslinger PW, Bowyer TW, Achim P, Chai T, Deconninck B, Freeman K, Generoso S, Hayes P, Heidmann V, Hoffman I, Kijima Y, Krysta M, Malo A, Maurer C, Ngan F, Robins P, Ross JO, Saunier O, Schlosser C, Schöppner M, Schrom BT, Seibert P, Stein AF, Ungar K, Yi J. International challenge to predict the impact of radioxenon releases from medical isotope production on a comprehensive nuclear test ban treaty sampling station. J Environ Radioact 2016; 157:41-51. [PMID: 26998569 DOI: 10.1016/j.jenvrad.2016.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 03/01/2016] [Accepted: 03/02/2016] [Indexed: 06/05/2023]
Abstract
The International Monitoring System (IMS) is part of the verification regime for the Comprehensive Nuclear-Test-Ban-Treaty Organization (CTBTO). At entry-into-force, half of the 80 radionuclide stations will be able to measure concentrations of several radioactive xenon isotopes produced in nuclear explosions, and then the full network may be populated with xenon monitoring afterward. An understanding of natural and man-made radionuclide backgrounds can be used in accordance with the provisions of the treaty (such as event screening criteria in Annex 2 to the Protocol of the Treaty) for the effective implementation of the verification regime. Fission-based production of (99)Mo for medical purposes also generates nuisance radioxenon isotopes that are usually vented to the atmosphere. One of the ways to account for the effect emissions from medical isotope production has on radionuclide samples from the IMS is to use stack monitoring data, if they are available, and atmospheric transport modeling. Recently, individuals from seven nations participated in a challenge exercise that used atmospheric transport modeling to predict the time-history of (133)Xe concentration measurements at the IMS radionuclide station in Germany using stack monitoring data from a medical isotope production facility in Belgium. Participants received only stack monitoring data and used the atmospheric transport model and meteorological data of their choice. Some of the models predicted the highest measured concentrations quite well. A model comparison rank and ensemble analysis suggests that combining multiple models may provide more accurate predicted concentrations than any single model. None of the submissions based only on the stack monitoring data predicted the small measured concentrations very well. Modeling of sources by other nuclear facilities with smaller releases than medical isotope production facilities may be important in understanding how to discriminate those releases from releases from a nuclear explosion.
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Affiliation(s)
- Paul W Eslinger
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA, 99352, USA.
| | - Ted W Bowyer
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA, 99352, USA.
| | - Pascal Achim
- Commissariat à l'Energie Atomique, CEA, DAM, DIF, 91297, Arpajon, France.
| | - Tianfeng Chai
- NOAA/Air Resources Laboratory, College Park, MD, USA.
| | | | | | - Sylvia Generoso
- Commissariat à l'Energie Atomique, CEA, DAM, DIF, 91297, Arpajon, France.
| | - Philip Hayes
- Air Force Technical Applications Center, Patrick Air Force Base, FL, USA.
| | - Verena Heidmann
- Federal Office for Radiation Protection (Bundesamt für Strahlenschutz, BfS), Frieburg, Germany
| | - Ian Hoffman
- Health Canada, Radiation Protection Bureau, Ottawa, Canada.
| | | | - Monika Krysta
- Comprehensive Test Ban Treaty Organization (CTBTO), International Data Center, Vienna, Austria.
| | - Alain Malo
- Environment Canada, Canadian Meteorological Centre, Dorval, Canada
| | - Christian Maurer
- Zentralanstalt für Meteorologie und Geodynamik, Vienna, Austria.
| | - Fantine Ngan
- NOAA/Air Resources Laboratory, College Park, MD, USA.
| | - Peter Robins
- AWE, Aldermaston, Reading, RG7 4PR, United Kingdom.
| | - J Ole Ross
- Federal Institute for Geosciences and Natural Resources (BGR), Hannover, Germany.
| | - Olivier Saunier
- French Institute for Radiation Protection and Nuclear Safety, Fontenay-aux-Roses, France.
| | - Clemens Schlosser
- Federal Office for Radiation Protection (Bundesamt für Strahlenschutz, BfS), Frieburg, Germany.
| | - Michael Schöppner
- Program on Science and Global Security, Princeton University, Princeton, NJ, USA.
| | - Brian T Schrom
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA, 99352, USA.
| | - Petra Seibert
- University of Natural Resources and Life Sciences, Institute of Meteorology and University of Vienna, Department of Meteorology and Geophysics, Vienna, Austria.
| | - Ariel F Stein
- NOAA/Air Resources Laboratory, College Park, MD, USA.
| | - Kurt Ungar
- Health Canada, Radiation Protection Bureau, Ottawa, Canada.
| | - Jing Yi
- Health Canada, Radiation Protection Bureau, Ottawa, Canada
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15
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Guillon S, Sun Y, Purtschert R, Raghoo L, Pili E, Carrigan CR. Alteration of natural (37)Ar activity concentration in the subsurface by gas transport and water infiltration. J Environ Radioact 2016; 155-156:89-96. [PMID: 26939033 DOI: 10.1016/j.jenvrad.2016.02.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 02/20/2016] [Accepted: 02/20/2016] [Indexed: 06/05/2023]
Abstract
High (37)Ar activity concentration in soil gas is proposed as a key evidence for the detection of underground nuclear explosion by the Comprehensive Nuclear Test-Ban Treaty. However, such a detection is challenged by the natural background of (37)Ar in the subsurface, mainly due to Ca activation by cosmic rays. A better understanding and improved capability to predict (37)Ar activity concentration in the subsurface and its spatial and temporal variability is thus required. A numerical model integrating (37)Ar production and transport in the subsurface is developed, including variable soil water content and water infiltration at the surface. A parameterized equation for (37)Ar production in the first 15 m below the surface is studied, taking into account the major production reactions and the moderation effect of soil water content. Using sensitivity analysis and uncertainty quantification, a realistic and comprehensive probability distribution of natural (37)Ar activity concentrations in soil gas is proposed, including the effects of water infiltration. Site location and soil composition are identified as the parameters allowing for a most effective reduction of the possible range of (37)Ar activity concentrations. The influence of soil water content on (37)Ar production is shown to be negligible to first order, while (37)Ar activity concentration in soil gas and its temporal variability appear to be strongly influenced by transient water infiltration events. These results will be used as a basis for practical CTBTO concepts of operation during an OSI.
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Affiliation(s)
- Sophie Guillon
- GEOTOP, Département des sciences de la Terre et de l'atmosphère, Université du Québec à Montréal, CP8888 Succ. Centre-Ville, Montreal, QC, Canada.
| | - Yunwei Sun
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA, 94550, United States.
| | - Roland Purtschert
- Climate-Environmental Physics, Physics Institute, University of Bern, Switzerland, Sidlerstrasse 5, CH-3012, Berne, Switzerland.
| | - Lauren Raghoo
- Climate-Environmental Physics, Physics Institute, University of Bern, Switzerland, Sidlerstrasse 5, CH-3012, Berne, Switzerland.
| | - Eric Pili
- CEA, DAM, DIF, F-91297, Arpajon, France.
| | - Charles R Carrigan
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA, 94550, United States.
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16
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Britton R, Jackson MJ, Davies AV. Quantifying radionuclide signatures from a γ-γ coincidence system. J Environ Radioact 2015; 149:158-163. [PMID: 26254208 DOI: 10.1016/j.jenvrad.2015.07.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 07/23/2015] [Indexed: 06/04/2023]
Abstract
A method for quantifying gamma coincidence signatures has been developed, and tested in conjunction with a high-efficiency multi-detector system to quickly identify trace amounts of radioactive material. The γ-γ system utilises fully digital electronics and list-mode acquisition to time-stamp each event, allowing coincidence matrices to be easily produced alongside typical 'singles' spectra. To quantify the coincidence signatures a software package has been developed to calculate efficiency and cascade summing corrected branching ratios. This utilises ENSDF records as an input, and can be fully automated, allowing the user to quickly and easily create/update a coincidence library that contains all possible γ and conversion electron cascades, associated cascade emission probabilities, and true-coincidence summing corrected γ cascade detection probabilities. It is also fully searchable by energy, nuclide, coincidence pair, γ multiplicity, cascade probability and half-life of the cascade. The probabilities calculated were tested using measurements performed on the γ-γ system, and found to provide accurate results for the nuclides investigated. Given the flexibility of the method, (it only relies on evaluated nuclear data, and accurate efficiency characterisations), the software can now be utilised for a variety of systems, quickly and easily calculating coincidence signature probabilities.
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17
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Eslinger PW, Cameron IM, Dumais JR, Imardjoko Y, Marsoem P, McIntyre JI, Miley HS, Stoehlker U, Widodo S, Woods VT. Source term estimates of radioxenon released from the BaTek medical isotope production facility using external measured air concentrations. J Environ Radioact 2015; 148:10-15. [PMID: 26093852 DOI: 10.1016/j.jenvrad.2015.05.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 05/26/2015] [Accepted: 05/29/2015] [Indexed: 06/04/2023]
Abstract
BATAN Teknologi (BaTek) operates an isotope production facility in Serpong, Indonesia that supplies (99m)Tc for use in medical procedures. Atmospheric releases of (133)Xe in the production process at BaTek are known to influence the measurements taken at the closest stations of the radionuclide network of the International Monitoring System (IMS). The purpose of the IMS is to detect evidence of nuclear explosions, including atmospheric releases of radionuclides. The major xenon isotopes released from BaTek are also produced in a nuclear explosion, but the isotopic ratios are different. Knowledge of the magnitude of releases from the isotope production facility helps inform analysts trying to decide if a specific measurement result could have originated from a nuclear explosion. A stack monitor deployed at BaTek in 2013 measured releases to the atmosphere for several isotopes. The facility operates on a weekly cycle, and the stack data for June 15-21, 2013 show a release of 1.84 × 10(13) Bq of (133)Xe. Concentrations of (133)Xe in the air are available at the same time from a xenon sampler located 14 km from BaTek. An optimization process using atmospheric transport modeling and the sampler air concentrations produced a release estimate of 1.88 × 10(13) Bq. The same optimization process yielded a release estimate of 1.70 × 10(13) Bq for a different week in 2012. The stack release value and the two optimized estimates are all within 10% of each other. Unpublished production data and the release estimate from June 2013 yield a rough annual release estimate of 8 × 10(14) Bq of (133)Xe in 2014. These multiple lines of evidence cross-validate the stack release estimates and the release estimates based on atmospheric samplers.
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Affiliation(s)
- Paul W Eslinger
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, WA 99352 USA.
| | - Ian M Cameron
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, WA 99352 USA.
| | | | - Yudi Imardjoko
- P.T. BATAN Teknologi, Puspiptek, Serpong 15310, Indonesia.
| | - Pujadi Marsoem
- P.T. BATAN Teknologi, Puspiptek, Serpong 15310, Indonesia.
| | - Justin I McIntyre
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, WA 99352 USA.
| | - Harry S Miley
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, WA 99352 USA.
| | - Ulrich Stoehlker
- Federal Office for Radiation Protection, Rosastr. 9, D-78098, Freiburg, Germany.
| | - Susilo Widodo
- National Nuclear Energy Agency of Indonesia (BATAN), Jl. Kuningan Barat, Mampang Prapatan Jakarta, 12710, Indonesia.
| | - Vincent T Woods
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, WA 99352 USA.
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18
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Eslinger PW, Bowyer TW, Cameron IM, Hayes JC, Miley HS. Atmospheric plume progression as a function of time and distance from the release point for radioactive isotopes. J Environ Radioact 2015; 148:123-129. [PMID: 26151301 DOI: 10.1016/j.jenvrad.2015.06.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 06/23/2015] [Accepted: 06/25/2015] [Indexed: 06/04/2023]
Abstract
The radionuclide network of the International Monitoring System comprises up to 80 stations around the world that have aerosol and xenon monitoring systems designed to detect releases of radioactive materials to the atmosphere from nuclear explosions. A rule of thumb description of plume concentration and duration versus time and distance from the release point is useful when designing and deploying new sample collection systems. This paper uses plume development from atmospheric transport modeling to provide a power-law rule describing atmospheric dilution factors as a function of distance from the release point. Consider the plume center-line concentration seen by a ground-level sampler as a function of time based on a short-duration ground-level release of a nondepositing radioactive tracer. The concentration C (Bq m(-3)) near the ground varies with distance from the source with the relationship C=R×A(D,C) ×e (-λ(-1.552+0.0405×D)) × 5.37×10(-8) × D(-2.35) where R is the release magnitude (Bq), D is the separation distance (km) from the ground level release to the measurement location, λ is the decay constant (h(-1)) for the radionuclide of interest and AD,C is an attenuation factor that depends on the length of the sample collection period. This relationship is based on the median concentration for 10 release locations with different geographic characteristics and 365 days of releases at each location, and it has an R(2) of 0.99 for 32 distances from 100 to 3000 km. In addition, 90 percent of the modeled plumes fall within approximately one order of magnitude of this curve for all distances.
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Affiliation(s)
- Paul W Eslinger
- Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, WA, USA.
| | - Ted W Bowyer
- Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, WA, USA.
| | - Ian M Cameron
- Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, WA, USA.
| | - James C Hayes
- Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, WA, USA.
| | - Harry S Miley
- Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, WA, USA.
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19
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Eslinger PW, Friese JI, Lowrey JD, McIntyre JI, Miley HS, Schrom BT. Estimates of radioxenon released from Southern Hemisphere medical isotope production facilities using measured air concentrations and atmospheric transport modeling. J Environ Radioact 2014; 135:94-99. [PMID: 24811887 DOI: 10.1016/j.jenvrad.2014.04.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 04/09/2014] [Accepted: 04/10/2014] [Indexed: 06/03/2023]
Abstract
The International Monitoring System (IMS) of the Comprehensive-Nuclear-Test-Ban-Treaty monitors the atmosphere for radioactive xenon leaking from underground nuclear explosions. Emissions from medical isotope production represent a challenging background signal when determining whether measured radioxenon in the atmosphere is associated with a nuclear explosion prohibited by the treaty. The Australian Nuclear Science and Technology Organisation (ANSTO) operates a reactor and medical isotope production facility in Lucas Heights, Australia. This study uses two years of release data from the ANSTO medical isotope production facility and (133)Xe data from three IMS sampling locations to estimate the annual releases of (133)Xe from medical isotope production facilities in Argentina, South Africa, and Indonesia. Atmospheric dilution factors derived from a global atmospheric transport model were used in an optimization scheme to estimate annual release values by facility. The annual releases of about 6.8 × 10(14) Bq from the ANSTO medical isotope production facility are in good agreement with the sampled concentrations at these three IMS sampling locations. Annual release estimates for the facility in South Africa vary from 2.2 × 10(16) to 2.4 × 10(16) Bq, estimates for the facility in Indonesia vary from 9.2 × 10(13) to 3.7 × 10(14) Bq and estimates for the facility in Argentina range from 4.5 × 10(12) to 9.5 × 10(12) Bq.
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Affiliation(s)
- Paul W Eslinger
- Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, WA, USA.
| | - Judah I Friese
- Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, WA, USA.
| | - Justin D Lowrey
- Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, WA, USA.
| | - Justin I McIntyre
- Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, WA, USA.
| | - Harry S Miley
- Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, WA, USA.
| | - Brian T Schrom
- Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, WA, USA.
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20
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Cagniant A, Le Petit G, Nadalut B, Gross P, Richard-Bressand H, Fontaine JP, Douysset G. On the use of (127)Xe standards for the quality control of CTBTO noble gas stations and support laboratories. Appl Radiat Isot 2014; 89:176-85. [PMID: 24657473 DOI: 10.1016/j.apradiso.2014.02.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 02/04/2014] [Accepted: 02/05/2014] [Indexed: 11/16/2022]
Abstract
(127)Xe has a longer half-life than (131m)Xe, it can be easily purely produced and it is present in the environment at very low level. For these reasons, (127)Xe is supposed to be a convenient quality control radionuclide for remote noble gas stations of the International Monitoring System (IMS) network. As CEA/DAM has recently developed two new photon/electron setups for low-level detection of (131m)Xe, (133m)Xe, (133)Xe and (135)Xe, we took the opportunity to test these setups for the measurement of a (127)Xe standard. The results and a detailed description of these measurements are presented in this paper. They illustrate the complexity of (127)Xe decay, emitting simultaneously several γ, X-rays, conversion electrons and Auger electrons; this results in highly summated coincidence spectra. The measurements performed provide precise electron energy calibration of the setups. The count rate of electrons in coincidence with iodine Kα X-rays was found to be surprisingly low, leading to the study of electron-gated photon spectrum. Finally, a comparison of three photon/electron coincidence spectra obtained with three different setups is given. The use of (127)Xe as a standard for energy calibration of IMS noble gas station is possible, but it appears to be quite complicated for efficiency check of noble gas station equipped with β/γ detectors.
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Affiliation(s)
| | | | - B Nadalut
- Preparatory Commission for the Comprehensive Nuclear Test Ban Treaty Organization, Provisional Technical Secretariat, P.O. Box 1200, 1400 Vienna, Austria
| | - P Gross
- CEA, DAM, DIF, F-91297 Arpajon, France
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Cagniant A, Le Petit G, Gross P, Douysset G, Richard-Bressand H, Fontaine JP. Improvements of low-level radioxenon detection sensitivity by a state-of-the art coincidence setup. Appl Radiat Isot 2013; 87:48-52. [PMID: 24332879 DOI: 10.1016/j.apradiso.2013.11.078] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 11/20/2013] [Indexed: 11/29/2022]
Abstract
The ability to quantify isotopic ratios of 135, 133 m, 133 and 131 m radioxenon is essential for the verification of the Comprehensive Nuclear-Test Ban Treaty (CTBT). In order to improve detection limits, CEA has developed a new on-site setup using photon/electron coincidence (Le Petit et al., 2013. J. Radioanal. Nucl. Chem., DOI : 10.1007/s 10697-013-2525-8.). Alternatively, the electron detection cell equipped with large silicon chips (PIPS) can be used with HPGe detector for laboratory analysis purpose. This setup allows the measurement of β/γ coincidences for the detection of (133)Xe and (135)Xe; and K-shell Conversion Electrons (K-CE)/X-ray coincidences for the detection of (131m)Xe, (133m)Xe and (133)Xe as well. Good energy resolution of 11 keV at 130 keV and low energy threshold of 29 keV for the electron detection were obtained. This provides direct discrimination between K-CE from (133)Xe, (133m)Xe and (131m)Xe. Estimation of Minimum Detectable Activity (MDA) for (131m)Xe is in the order of 1mBq over a 4 day measurement. An analysis of an environmental radioxenon sample using this method is shown.
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Affiliation(s)
| | | | - P Gross
- CEA, DAM, DIF, F-91297 Arpajon, France
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Orr B, Schöppner M, Tinker R, Plastino W. Detection of radioxenon in Darwin, Australia following the Fukushima Dai-ichi nuclear power plant accident. J Environ Radioact 2013; 126:40-44. [PMID: 23933085 DOI: 10.1016/j.jenvrad.2013.07.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 07/01/2013] [Accepted: 07/02/2013] [Indexed: 06/02/2023]
Abstract
A series of (133)Xe detections in April 2011 made at the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO) International Monitoring System noble gas station in Darwin, Australia, were analysed to determine the most likely source location. Forward and backwards atmospheric transport modelling simulations using FLEXPART were conducted. It was shown that the most likely source location was the Fukushima Dai-ichi nuclear power plant accident. Other potential sources in the southern hemisphere were analysed, including the Australian Nuclear Science and Technology Organisation (ANSTO) radiopharmaceutical facility, but it was shown that sources originating from these locations were highly unlikely to be the source of the observed (133)Xe Darwin detections.
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Affiliation(s)
- Blake Orr
- Australian Radiation Protection and Nuclear Safety Agency (ARPANSA), 619 Lower Plenty Road, Yallambie, Victoria 3085, Australia.
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