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Maurer, C.*; Galmarini, S.*; Solazzo, E.*; Ku
mierczyk-Michulec, J.*; Bar
, J.*; Kalinowski, M.*; Schoeppner, M.*; Bourgouin, P.*; Crawford, A.*; Stein, A.*; et al.
Journal of Environmental Radioactivity, 255, p.106968_1 - 106968_27, 2022/12
Times Cited Count：4 Percentile：37.30(Environmental Sciences)After performing multi-model exercises in 2015 and 2016, a comprehensive Xe-133 atmospheric transport modeling challenge was organized in 2019. For evaluation measured samples for the same time frame were gathered from four International Monitoring System stations located in Europe and North America with overall considerable influence of IRE and/or CNL emissions. As a lesion learnt from the 2nd ATM-Challenge participants were prompted to work with controlled and harmonized model set ups to make runs more comparable, but also to increase diversity. Effects of transport errors, not properly characterized remaining emitters and long IMS sampling times (12 to 24 hours) undoubtedly interfere with the effect of high-quality IRE and CNL stack data. An ensemble based on a few arbitrary submissions is good enough to forecast the Xe-133 background at the stations investigated. The effective ensemble size is below five.
Maurer, C.*; Bar, J.*; Kusmierczyk-Michulec, J.*; Crawford, A.*; Eslinger, P. W.*; Seibert, P.*; Orr, B.*; Philipp, A.*; Ross, O.*; Generoso, S.*; et al.
Journal of Environmental Radioactivity, 192, p.667 - 686, 2018/12
Times Cited Count：25 Percentile：63.55(Environmental Sciences)It is very important to understand the impact for CTBT stations caused by radioxenon emitted from medical isotope production facilities for detection of underground nuclear tests. Predictions of the impact on six CTBT radionuclide stations in the Southern Hemisphere of radioxenon emitted from the medical isotope production facility in Australia were carried out by participants from ten nations using ATM (Atmospheric Transport Modeling) based on the emission data of radioxenon from this facility, as part of study on impact of radioxenon emitted from medical isotope production facilities on CTBT radionuclide stations.
Kijima, Yuichi; Yamamoto, Yoichi; Oda, Tetsuzo
JAEA-Technology 2017-028, 33 Pages, 2018/01
JAEA-Technology-2017-028.pdf:38.85MB
The International Noble Gas Experiment related to monitoring network for radioactive noble gas (xenon) has been carried out all over the world, as part of the International Monitoring System (IMS) of CTBT. Thirty IMS radionuclide stations including the Takasaki station in Japan are monitoring radioxenon. The past measurement results show that several stations often detect radioxenon and the major emission source of these radioxenon is medical radioisotope production facilities. And nuclear power plants and medical institutions used radioxenon for nuclear medicine diagnosis, and so on are also considered as the possible sources of radioxenon, and it is therefore important to understand the background behavior of radioxenon originated from above facilities for enhancement of monitoring capability for nuclear tests. The international joint measurement was conducted in 2012 by the Preparatory Commission for the CTBT Organization, US Pacific Northwest National Laboratory, Japan Chemical Analysis Center and JAEA at the Ohminato site of JAEA Aomori Research and Development Center in Mutsu city, Aomori, as part of investigation on radioxenon background in East Asia region. In 2014, the additional measurement was carried out at the same place for further investigation. A high sensitive Transportable Xenon Laboratory developed by PNNL was used for this measurement. This paper describes the outline and the results of the joint measurement conducted in 2012 and 2014.
Eslinger, P. W.*; Bowyer, T. W.*; Achim, P.*; Chai, T.*; Deconninck, B*; Freeman, K.*; Generoso, S.*; Hayes, P.*; Heidmann, V.*; Hoffman, I.*; et al.
Journal of Environmental Radioactivity, 157, p.41 - 51, 2016/06
Times Cited Count：36 Percentile：72.71(Environmental Sciences)It is very important to understand the impact for CTBT stations caused by radioxenon emitted from nuclear facilities and medical isotope production facilities for detection of underground nuclear tests. Predictions of the impact on the CTBT radionuclide station in Germany of radioxenon emitted from the medical isotope production facility in Belgium were carried out by participants from seven nations using ATM (Atmospheric Transport Modeling) based on the emission data of radioxenon from this facility, as part of study on impact of radioxenon emitted from medical isotope production facilities on CTBT radionuclide stations.
Kijima, Yuichi; Yamamoto, Yoichi
Nihon Genshiryoku Gakkai-Shi ATOMO
, 58(3), p.156 - 160, 2016/03
JAEA has built and operated two radionuclide stations and a certified laboratory for monitoring of radionuclide out of facilities of the International Monitoring System (IMS) under the CTBT National Operation System of Japan. JAEA also has developed and operated the National Data Center for analysis and evaluation of radionuclide observation data obtained from the IMS station. In this paper, we explain the outline of the CTBT and the CTBT activities of JAEA, and introduce two examples of detection of some anthropogenic radionuclides including the monitoring case for the DPRK's 3rd nuclear test in February 2013 from all observational results obtained from the CTBT radionuclide stations in Japan.
Kijima, Yuichi; Yamamoto, Yoichi; Oda, Tetsuzo
no journal, ,
More than 80% facilities (275 places) of the International Monitoring System prescribed in the Comprehensive Nuclear-Test-Ban Treaty (CTBT) have already been completed and have been substantially functioning as a global nuclear test monitoring. Of facilities installed in Japan, the JAEA has established 2 radionuclide stations which monitor radionuclides and 1 laboratory which performs detail analyses of samples sent from stations all over the world, and is operating them as certified facilities which meet technical requirements for the Treaty monitoring. The National Data Center installed in JAEA's site receives the data from station network and analyzes it routinely. This paper describes current status of the verification regime and JAEA's recent activities related to the CTBT such as DPRK's 3rd nuclear test event.
Kijima, Yuichi; Yamamoto, Yoichi; Oda, Tetsuzo
no journal, ,
Following the claimed nuclear test in the Democratic People's Republic of Korea (DPRK) on 12 February 2013, spectral analysis of radionuclide and ATM simulation were performed by the NDC-2 in Japan which is in charge of analysing radionuclides. There was no detection of artificial radioactive particulates. However, there were several detections of radioxenon, although each activity concentration was not far beyond the normal background range. We tried to estimate upper limit of radioxenon release in the DPRK event by using IMS data and the ATM simulation. The upper limit of Xe-133 release was estimated about 10
- 10
Bq.
Yamamoto, Yoichi; Kijima, Yuichi; Oda, Tetsuzo
no journal, ,
The Japanese NDC-2 estimated the movement of virtual radioactive plume by the Atmospheric Transport Modelling (ATM) simulations with regard to the DPRK 2016 event. The simulations were done in two hypothetical cases of coincident and delayed emission of radionuclides. The NDC-2 decided which IMS radionuclide stations should be monitored based on the simulation results. As the result, no radionuclides generated from the nuclear explosion were found in any IMS data obtained from the selected radionuclide stations in January. However, xenon-133 with high activity concentration above the normal background levels was detected 5 times at the Takasaki station in the middle of February. The NDC-2 estimated the location of emission source of the Xe-133 by ATM backward tracking simulations. Some ATM simulations and the analysis results by the NDC-2 are shown in the presentation.
Kijima, Yuichi; Yamamoto, Yoichi; Oda, Tetsuzo
no journal, ,
The International Noble Gas Experiment (INGE) is being carried out for global measurement networks of radioactive noble gas (xenon), as part of building of the international verification regime of the Comprehensive nuclear-Test-Ban Treaty (CTBT). Since there are many nuclear facilities and medical institutions in Japan and its neighboring countries, which may be possible sources of radioxenon, it is important to understand the behavior of normal radioxenon background for high-precision detection of underground nuclear tests. Therefore, for the purpose of the investigation on radioxenon background in Northeast Asia region, the measurement of radioxenon was conducted in Mutsu city, Aomori in 2012, and the results showed that radioxenon background in Mutsu was regionally specific and different from that in Takasaki. In 2014, the additional measurement was carried out at the same place for further investigation. This report describes the results of background measurement in Mutsu city in 2014.
Otsu, Takayuki*; Arai, Nobuo*; Nogami, Mami*; Kijima, Yuichi; Yamamoto, Yoichi; Oda, Tetsuzo
no journal, ,
Japan has two kinds of NDCs, one is NDC-1 in charge of analysis of SHI data and the other is NDC-2 in charge of RN issue. Both NDCs participated in the NDC preparedness Exercise (NPE) 2012 and tried to get results collaboratively. In this exercise, NDC-2 made backward and forward tracking using ATM. NDC-1 tried to select one event from among several candidate events by the result of ATM and made some seismo-acoustic analysis. NDC-1 tried to sift through candidate events from REB using the results from NDC-2. Finally two possible candidate events were selected. These events are located around Mezhdurechensk, Kemerovo Oblast, Russia. It was very difficult to distinguish which event was the candidate event, because these waveforms have similar characteristics each other and look like small explosion.
Fujii, Takanari*; Otsu, Takayuki*; Yagi, Masanori*; Yonezawa, Chushiro*; Jih, R.*; Kalinowski, M.*; Kang, I.-B.*; Chi, H.-C.*; Yamamoto, Yoichi; Kijima, Yuichi
no journal, ,
As a part of East Asia Regional NDC Workshop 2014 Mongolia (EARNW2014), the common exercise took place for the purpose of investigation from both of radionuclide and waveform analysis. Each participating NDC analyzed distributed fictitious RN data and real SHI data including non-IMS to find and investigate candidate event. The Japanese NDC-1 (JWA) tried to locate and discriminate the event utilizing local seismic observation data such as NECESSArray (NorthEast China Extended SeiSmic Array) and Korean local data kindly provided by KIGAM. Signals from this event were detected at many stations in such non-IMS network, and it indicated that these local/regional seismic data could contribute largely to estimate more reliable event location and discrimination.
Kijima, Yuichi; Yamamoto, Yoichi
no journal, ,
The flow of analysis for nuclear test event in the Japanese NDC-2 will be presented. When the information on a nuclear test event is obtained from the Secretariat of the CTBT National operation system of Japan (NOSJ), the first thing to be done in the NDC-2 is to forecast a possible movement of a virtual radioactive plume emitted from the nuclear test site by the ATM analysis. Based on the analysis results, radionuclide stations to be monitored are selected and the radionuclide data from the stations are analysed in detail. The results of both the ATM analysis and the radionuclide analysis are reported to the Secretariat of NOSJ. A part of studies on the released condition of the ATM analysis will also be presented.
Yamamoto, Yoichi; Kijima, Yuichi; Tomita, Yutaka
no journal, ,
This presentation summarizes JAEA's recent activities related to CTBT verification regime. To establish the global verification regime of CTBT for the nuclear tests, JAEA has been operating provisionally three facilities (two monitoring stations and one radionuclide laboratory) of the CTBT international monitoring system and a national data center for radionuclide monitoring. For the 6th nuclear test conducted by North Korea in September 2017, JAEA reported the analysis and evaluation results of data observed at the CTBT radionuclide monitoring stations to the national government etc. in a timely manner and thereby contributed to the evaluation by the national government based on the CTBT operation system in Japan. For the purpose of strengthening CTBTO's detection capability for nuclear tests, JAEA started new noble gas joint measurement project with CTBTO in Horonobe (Hokkaido) and Mutsu (Aomori) based on the Japanese government contribution in 2017.
Yamamoto, Yoichi; Kijima, Yuichi; Tomita, Yutaka
no journal, ,
Based on repeated DPRK's nuclear tests, the Japanese government contributed funds for the noble gas measurement project in February 2017 for the purpose of strengthening CTBTO's detection capability for nuclear tests. The CTBTO decided to conduct measurements in Hokkaido and Tohoku regions of Japan for the time being, and to enhance JAEA with experiences and performance of measurements in Japan as the responsible organization. In response to this, the JAEA has installed two mobile noble gas measurement systems at Horonobe, Hokkaido and JAEA Ohminato site in Mutsu, Aomori, and been carrying out the joint measurement project with the CTBTO. The current status of this project will be presented.
Kijima, Yuichi; Yamamoto, Yoichi
no journal, ,
The two overall performance grades (activity and activity concentration) of JPL11 in PTE2016 were both A-, because the zeta test for one major nuclide (Co-58) failed. And in PTE2017, since the %difference test for one major nuclide (Ag-111) failed, the two overall performance grades resulted in both A-. Therefore, we investigated the cause of these discrepancy between JPL11 activity results and the reference activities, and the corrective actions were carried out. We report the analysis results and the taken corrective actions in PTE2016 and PTE2017 respectively at JPL11.
Yamamoto, Yoichi; Kijima, Yuichi
no journal, ,
Following the 6th DPRK nuclear test (DPRK-6) event on 3 September 2017, some Level C events of 
Xe were detected at the Takasaki radionuclide (RN) station and the Hawaii RN station in October. In order to investigate the relation between those Level C events and the DPRK-6 event, the Japanese NDC-2 carried out the ATM analysis for the Level C events. The estimation results of the possible source region using the ATM backtracking analysis show the DPRK test site is included in the possible source region. However, the results of the ATM forward tracking analysis from the DPRK test site disagree with the real measurement results at Takasaki and Hawaii RN stations. Some analysis results of ATM simulations by the NDC-2 and our conclusion for the Level C events at Takasaki and Hawaii are shown in the presentation.
Kijima, Yuichi; Yamamoto, Yoichi; Tomita, Yutaka
no journal, ,
The Japan Atomic Energy Agency has been conducting the measurement of radioxenon using the transportable xenon laboratories (TXLs) at Horonobe, Hokkaido and Mutsu, Aomori since 2018, as part of the noble gas joint measurement project with CTBTO, which is aimed at contribution in better understandings of the measurement data obtained at the CTBT International Monitoring System (IMS) Takasaki radionuclide station. The comparison among the measurement results of radioxenons at 3 measuring points (Horonobe, Mutsu and Takasaki) since 2018, and the analyses results by atmospheric transport modelling (ATM) on estimation of emission source of radioxenon detected will be reported.
Furuno, Akiko; Kijima, Yuichi; Tomita, Yutaka; Yamamoto, Yoichi
no journal, ,
This research aims at source term estimations of high-concentration detection events of Xe-133, which were observed at the CTBT IMS (International Monitoring System) Takasaki radionuclide monitoring station from the viewpoint of atmospheric dispersion analysis. Japan Atomic Energy Agency operates JPX38 in the Takasaki radionuclide station for noble gas monitoring, and conducts temporary measurement project of radioxenon at Horonobe in Hokkaido (JPX81) and Mutsu in Aomori (MUX88) as a part of the noble gas joint measurement project with CTBTO. The high-concentration detection events were frequently occurred not only at the JPX38 but also at the JPX81from the end of 2020 to January 2021. In the presentation, we will describe the source term estimation analysis of these high-concentration detection events, and discuss the relationship of the events between two stations.
Kijima, Yuichi; Yamamoto, Yoichi
no journal, ,
The JPX38 Level C episode of 8-9 April 2013 is thought of as delayed release from the DPRK 2013 event from the aspect of the radioxenon isotope ratio and the result of the possible source location analysis. The Japanese NDC-2 carried out the comparison of radioxenon detections between the DPRK 2013 event and the DPRK 2016 events. The results of the possible source location analysis for the JPX38 Level C episode of 17-19 February 2016 and the CNX22 episode of 22-24 September 2016 will also be presented.
Yonezawa, Chushiro*; Yamamoto, Yoichi; Kijima, Yuichi; Kalinowski, M.*
no journal, ,
The authors present a summary report of the analysis results of ATM (Atmospheric Transport Model) and radionuclide (RN) data of the common exercise in the 2014 East Asia Regional NDC Workshop 2014 (EARNW 2014) held in Ulaanbaatar, Mongolia from 29 July to 1 August, 2014. The exercise scenario was that CTBT-relevant RNs released from a hypothetical target event were detected in particulate and noble gas samples at the Takasaki station (RN38), and the target event was inferred using estimated explosion time from La-140/Ba-140 ratio in the particulate samples. The possible source area was determined through ATM backward tracking of Xe-133. Real observation noble gas data by a certified IMS station and artificially prepared particulate data were used as the fictitious RN data in this exercise. The analysis results of the RN data by the participating NDCs were evaluated by comparing with the prepared values for the particulate and IDC/RRR for the noble gas data. The results of estimated explosion time were evaluated by comparing to the preset value. Released Xe-133 activity from the event and the observable radioactivity concentration of Xe-133 at the IMS station were compared among the reported ATM results.
