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Journal Articles

International challenge to model the long-range transport of radioxenon released from medical isotope production to six Comprehensive Nuclear-Test-Ban Treaty monitoring stations

Maurer, C.*; Bar$'e$, 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:4 Percentile:65.1(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.

JAEA Reports

International Noble Gas joint measurement at Mutsu City, Aomori for CTBT verification

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.

Journal Articles

International challenge to predict the impact of radioxenon releases from medical isotope production on a comprehensive nuclear test ban treaty sampling station

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:22 Percentile:22.45(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.

Journal Articles

Monitoring of radionuclide related to CTBT

Kijima, Yuichi; Yamamoto, Yoichi

Nippon Genshiryoku Gakkai-Shi, 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.

Oral presentation

Study on noble gas behavior for CTBT verification regime; International Noble Gas Measurement at Mutsu city

Kijima, Yuichi; Inoue, Naoko; Yamamoto, Yoichi; Oda, Tetsuzo

no journal, , 

The International Noble Gas Experiment (INGE) is being carried out for global measurements of radioactive noble gas (radioxenons), as part of the international verification regime for the Comprehensive nuclear-Test-Ban Treaty (CTBT). There are many medical institutions and nuclear facilities in and around Japan, which are possible sources of radioxenons, and it is therefore important to understand their behavior of normal background for detection of underground nuclear tests. The joint measurement is conducted by US Pacific Northwest National Laboratory (PNNL) and JAEA. A transportable and high sensitive noble gas monitoring system developed by PNNL was installed at Mutsu city, Aomori, which was selected based on the information obtained by simulations with an atmospheric transport model and the field surveys. The measurement has been started for survey on noble gas behavior in and around Japan. This paper describes the outline and the preliminary results of measurement.

Oral presentation

Analysis result of NPE 2012 at Japanese NDC; Event selection using ATM and waveform analysis

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.

Oral presentation

Upper limit estimation of radioxenon release in DPRK 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$$^{12}$$ - 10$$^{13}$$ Bq.

Oral presentation

JAEA's recent activities related to Comprehensive Nuclear-Test-Ban Treaty (CTBT)

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.

Oral presentation

Detection of radioxenon at Takasaki and Ussuriisk in April 2013

Kijima, Yuichi; Yamamoto, Yoichi; Oda, Tetsuzo

no journal, , 

Following the third claimed nuclear test in DPRK on 12 February 2013 (DPRK-3), spectral analysis of radionuclide data and ATM simulation were performed by Japanese NDC-2 in charge of monitoring radionuclides. There was no significant detection of radioxenon in February 2013. However, early in April 2013, Xe-133 and Xe-131m were detected simultaneously far beyond normal background range of the activity concentration at Takasaki IMS station in Japan. And there were also simultaneous detections of Xe-133 and Xe-131m at Ussuriisk IMS station in Russia in mid-April, although these activity concentrations were within the normal background range. We studied the relations between these detections of radioxenon isotopes and DPRK-3 event.

Oral presentation

Summary report of ATM and radionuclide data analyses of the common exercise in the East Asia Regional NDC Workshop 2014

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.

Oral presentation

Application of the local seismic observation data for the common exercise in East Asia Regional NDC Workshop 2014

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.

Oral presentation

Investigation on radioxenon background in Mutsu related to CTBT verification

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.

Oral presentation

SAUNA system upgrade for certification of the Takasaki IMS station

Tomita, Yutaka; Kumata, Masahiro; Wakabayashi, Shuji; Kijima, Yuichi; Yamamoto, Yoichi; Oda, Tetsuzo

no journal, , 

Oral presentation

Study on emission source of radioxenon detected at Takasaki station

Kijima, Yuichi; Yamamoto, Yoichi; Oda, Tetsuzo

no journal, , 

It is very important to understand the behavior of background of radioxenon at the view point of monitoring of underground nuclear tests. Although all nuclear power plants (NPPs) in Japan had been shut down from 15th September 2013 to 10th August 2015, Xe-133 had been sometimes detected far beyond normal background level of the activity concentration at the CTBT Takasaki station (JPX38) during the same period. Therefore, radiopharmaceutical production facilities (RPFs) in Japan can be considered as one of the potential emission sources of Xe-133 detected at JPX38 in this period. We make a study on the possibility of RPFs as the emission source of these Xe-133 detections at JPX38 by ATM simulation.

Oral presentation

Analysis results of NPE 2015 by NDCs in Japan

Kijima, Yuichi; Yamamoto, Yoichi; Motohashi, Masashi*; Otsu, Takayuki*

no journal, , 

The CTBT National Operation System of Japan (NOSJ) consists of two NDCs, NDC-1 (Japan Weather Association; JWA) in charge of analysis of SHI data and NDC-2 (Japan Atomic Energy Agency; JAEA) in charge of analysis of RN data and ATM, and the Center for the Promotion of Disarmament and Non-Proliferation (CPDNP) which is the secretariat of NOSJ. The NDCs participated in the NDC preparedness exercise 2015 (NPE 2015). At first, NDC-2 made analysis of artificial (simulated) and real RN data for identification and quantification of RN, and ATM analysis for estimation of the possible source region. Then NDC-1 made analysis of seismic waveform to identify the epicenter using the result of NDC-2. Both NDCs tried to get a final conclusion collaboratively.

Oral presentation

ATM analysis of the DPRK 2016 event and the potentially relevant Level C episode at the Takasaki station

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.

Oral presentation

Analysis results of 2nd ATM challenge 2016 by JAEA/NDC

Kijima, Yuichi; Yamamoto, Yoichi; Oda, Tetsuzo

no journal, , 

It is very important to understand the impact of radioxenon emitted from nuclear facilities on the CTBT radionuclide stations for improvement of detection ability of underground nuclear tests. As part of study on the impact of radioxenon emitted from these facilities on the CTBT radionuclide stations, the 2nd ATM Challenge 2016 was carried out to quantify the impact of radioxenon from the Australian Nuclear Science and Technology Organisation (ANSTO) radiopharmaceutical plant in Australia by ATM analysis. JAEA/NDC participated in the 2nd ATM Challenge 2016 and performed ATM analysis by using the HYSPLIT code and the NCEP GDAS meteorological data. We report the analysis results.

Oral presentation

Nuclear test analysis in Japanese NDC-2; Analytical procedure and release condition for ATM

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.

Oral presentation

Comparison of radioxenon detections between the DPRK 2013 event and the DPRK

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.

Oral presentation

Detection of radioxenon at Takasaki and Guangzhou after DPRK nuclear tests in 2016 and 2017

Kijima, Yuichi; Yamamoto, Yoichi; Oda, Tetsuzo

no journal, , 

Xenon-133 was detected at CTBT Takasaki station in Japan (JPX38) after about 40 days from DPRK 4th nuclear test conducted on 6 January 2016 (DPRK-4). Xenon-133 and Xenon-131m were simultaneously detected at CTBT Guangzhou station in China (CNX22) after about 13 days from DRRK 5th nuclear test conducted on 9 September 2016 (DPRK-5). And Xenon-133 was detected at JPX38 after about 30 and 40 days from DRRK 6th nuclear test conducted on 3 September 2017 (DPRK-6). These radioxenon activity concentrations are all beyond background levels. We studied whether these radioxenon isotopes are originated from DPRK-4, DPRK-5 or DPRK-6 event though analysis by Atmospheric Transport Modelling (ATM).

34 (Records 1-20 displayed on this page)