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Kusano, Kanya*; Ichimoto, Kiyoshi*; Ishii, Mamoru*; Miyoshi, Yoshizumi*; Yoden, Shigeo*; Akiyoshi, Hideharu*; Asai, Ayumi*; Ebihara, Yusuke*; Fujiwara, Hitoshi*; Goto, Tadanori*; et al.
Earth, Planets and Space (Internet), 73(1), p.159_1 - 159_29, 2021/12
Times Cited Count：6 Percentile：51.19(Geosciences, Multidisciplinary)The PSTEP is a nationwide research collaboration in Japan and was conducted from April 2015 to March 2020, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan. It has made a significant progress in space weather research and operational forecasts, publishing over 500 refereed journal papers and organizing four international symposiums, various workshops and seminars, and summer school for graduate students at Rikubetsu in 2017. This paper is a summary report of the PSTEP and describes the major research achievements it produced.
-ray pipe-monitoring capabilities for real-time process monitoring safeguards applications in reprocessing facilitiesRodriguez, D.; Tanigawa, Masafumi; Nishimura, Kazuaki; Mukai, Yasunobu; Nakamura, Hironobu; Kurita, Tsutomu; Takamine, Jun; Suzuki, Satoshi*; Sekine, Megumi; Rossi, F.; et al.
Journal of Nuclear Science and Technology, 55(7), p.792 - 804, 2018/07
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)Nuclear material in reprocessing facilities is safeguarded by random sample verification with additional continuous monitoring applied to solution masses and volume in important tanks to maintain continuity-of-knowledge of process operation. Measuring the unique rays of each solution as the material flows through pipes connecting all tanks and process apparatuses could potentially improve process monitoring by verifying the compositions in real time. We tested this ray pipe-monitoring method using plutonium-nitrate solution transferred between tanks at the PCDF-TRP. The rays were measured using a lanthanum-bromide detector with a list-mode data acquisition system to obtain both time and energy of -ray. The analysis and results of this measurement demonstrate an ability to determine isotopic composition, process timing, flow rate, and volume of solution flowing through pipes, introducing a viable capability for process monitoring safeguards verification.
Mukai, Yasunobu; Nakamichi, Hideo; Kobayashi, Daisuke; Nishimura, Kazuaki; Fujisaku, Sakae; Tanaka, Hideki; Isomae, Hidemi; Nakamura, Hironobu; Kurita, Tsutomu; Iida, Masayoshi*; et al.
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 8 Pages, 2017/04
TRP has stored the plutonium in solution state for long-term since the last PCDF operation in 2007 was finished. After the great east Japan earthquake in 2011, JAEA had investigated the risk against potential hazard of these solutions which might lead to make hydrogen explosion and/or boiling of the solution accidents with the release of radioactive materials to the public when blackout. To reduce the risk for storing Pu solution (about 640 kg Pu), JAEA planned to perform the process operation for the solidification and stabilization of the solution by converted into MOX powder at PCDF in 2013. In order to perform PCDF operation without adaption of new safety regulation, JAEA conducted several safety measures such as emergency safety countermeasures, necessary security and safeguards (3S) measures with understanding of NRA. As a result, the PCDF operation had stared on 28th April, 2014, and successfully completed to convert MOX powder on 3rd August, 2016 for about 2 years as planned.
Nakamura, Hironobu; Nakamichi, Hideo; Mukai, Yasunobu; Hosoma, Takashi; Kurita, Tsutomu; LaFleur, A. M.*
Proceedings of International Conference on Mathematics & Computational Methods Applied to Nuclear Science & Engineering (M&C 2017) (USB Flash Drive), 7 Pages, 2017/04
In order to maintain facility nuclear material accountancy (NMA) and safeguards properly, to understand where and how much holdup deposit in the process is presence is very important for the cleanout before PIT. JAEA and LANL developed a GloveBox Cleanout Assistance Tool (BCAT) to help cleanout (MOX powder recovering in a glovebox) for invisible holdup effectively by computational approach which is called distributed source-term approach (DSTA). The BCAT tool is a simple neutron measurement slab detectors and helps operator to find locations of holdup. To know the holdup location and the activity from the neutron measurements, the relation between BCAT measurements results at predetermined positions (57 positions) and source voxels (53 voxels) that we want to know the holdup activity was mathematically defined as a matrix by the MCNPX simulation. The model of MCNPX for entire process is very precisely established. We have implemented and experimentally proved that the BCAT tool can direct the operator to recoverable holdup that would otherwise be accounted for as MUF. Reducing facility MUF results in a direct improvement of the facility NMA. The BCAT enables the staff to significantly improve their knowledge of the locations of residual holdup in the process area. JAEA would like to use this application for dismantling of the glovebox with transparency in the future.
He replacement technologies; Development of HLNB counterTanigawa, Masafumi; Mukai, Yasunobu; Nakamura, Hironobu; Kurita, Tsutomu; Henzlova, D.*; Menlove, H. O.*
Dai-37-Kai Kaku Busshitsu Kanri Gakkai Nihon Shibu Nenji Taikai Rombunshu (CD-ROM), 9 Pages, 2017/02
no abstracts in English
Shimizu, Yasuyuki; Makino, Risa; Mukai, Yasunobu; Ishiyama, Koichi; Kurita, Tsutomu; Nakamura, Hironobu
Dai-37-Kai Kaku Busshitsu Kanri Gakkai Nihon Shibu Nenji Taikai Rombunshu (CD-ROM), 9 Pages, 2017/02
no abstracts in English
Nakamura, Hironobu; Shimizu, Yasuyuki; Makino, Risa; Mukai, Yasunobu; Ishiyama, Koichi; Kurita, Tsutomu; Ikeda, Atsushi*; Yamaguchi, Katsuhiro*
Proceedings of INMM 57th Annual Meeting (Internet), 9 Pages, 2016/07
Regarding the Integrated Safeguards (IS) in Japan, the implementation of IS has been started on September 2004, and the concept has been introduced to the JNC-1 facilities since August 2008. Then, random interim inspection with short notice and reducing person-days of inspection (PDI) was introduced instead of traditional scheduled IIV in order to improve deterrence of the nuclear material diversion with timeliness goal. And it was agreed that it should be evaluated and reviewed because RII was designed when inter-campaign. In JAEA, we decided to restart PCDF campaign to reduce potential safety risks of reprocessing facilities. To adopt the RII scheme to the process operation in campaign, JAEA proposed a new scheme to JSGO and IAEA without increasing PDI and reducing detection probability. As a result of the discussion, it was agreed and successfully introduced since March 2014. The new scheme for PCDF consists of scheduled inspection (fixed-day RII), reduction of estimated material for the verification, implementation of remote monitoring with data provision, improvement of operational status check list, introduction of NRTA and MC&A data declaration with timeliness. Though the operator's workloads for information provision were increased, we could manage to balance IS requirement with implementation of our operation successfully. This contribution was helped to safeguards implementation and our operation for 2 years.
Mukai, Yasunobu; Ogawa, Tsuyoshi; Nakamura, Hironobu; Kurita, Tsutomu; Sekine, Megumi; Rodriguez, D.; Takamine, Jun; Koizumi, Mitsuo; Seya, Michio
Proceedings of INMM 57th Annual Meeting (Internet), 7 Pages, 2016/07
The development of Delayed Gamma-ray Spectroscopy (DGS) for analyzing the composition ratio of fissile nuclides (
Pu, 
Pu, 
U) focused on the Delayed Gamma-ray having energy over 3 MeV has been performed for the development of active neutron non-destructive assay techniques. In PCDF, measurement tests of Delayed Gamma-ray using Pu solution and MOX powder samples to prove the DGS technique is planned to be performed in following 4 stages. (1) Measurements for Delayed Gamma-ray originated from spontaneous fission nuclide (Passive), (2) Measurements for the Delayed Gamma-ray with fast neutron (Active), (3) DGSI (DGS combined with self-interrogation) measurements (Passive), (4) Measurements for the Delayed Gamma-ray with thermal neutron (Active) In this paper, the plan of measurement tests for nuclear material samples with use of DGS is presented.
Tanigawa, Masafumi; Mukai, Yasunobu; Tobita, Hiroshi; Kurata, Noritaka*; Kobayashi, Nozomi*; Takase, Misao*; Makino, Risa; Ozu, Akira; Nakamura, Hironobu; Kurita, Tsutomu; et al.
56th Annual Meeting of the Institute of Nuclear Materials Management (INMM 2015), Vol.1, p.693 - 701, 2016/00
no abstracts in English
He Alternative Neutron Detectors (ASAS), 1; Design and fabrication of ASAS detectorOzu, Akira; Tobita, Hiroshi; Kureta, Masatoshi; Tanigawa, Masafumi; Mukai, Yasunobu; Nakamichi, Hideo; Nakamura, Hironobu; Kurita, Tsutomu; Seya, Michio
Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-36-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2015/12
Against the background of the serious shortage of He gas, the Japan Atomic Energy Agency (JAEA) has newly developed an alternative ZnS ceramic scintillation neutron detector for the safeguards, with the support of the government (MEXT). A demonstrator of plutonium inventory sample assay system (ASAS) has been also developed as an alternative HLNCC (High Level Neutron Coincidence Counter). The results from numerical simulations using Monte-Carlo code MCNPX showed that the fundamental performances of ASAS equipped with the 24 alternative neutron detectors, such as neutron detection efficiency and die-away time, equal to or higher than those of conventional HLNCC could be obtained. Here we present the inner mechanical structure of ASAS, together with the results of the simulating design.
He Alternative Neutron Detectors (ASAS), 2; Results of ASAS measurement testTanigawa, Masafumi; Mukai, Yasunobu; Kurita, Tsutomu; Makino, Risa; Nakamura, Hironobu; Tobita, Hiroshi; Ozu, Akira; Kureta, Masatoshi; Seya, Michio
Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-36-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2015/12
Against the background of the serious shortage of He gas, design and development of a new detector equipped ZnS/
B
O
ceramic scintillation neutron detectors in JAEA, with the support of the government (the Ministry of Education, Culture, Sports, Science & Technology). The design of the alternative He detector is referred from INVS (INVentory Sample assay system (HLNCC (High Level Neutron Coincidence Counter) type)) which is being used for the verification of MOX powder etc. and is named it as ASAS (Alternative Sample Assay System). In order to prove the Pu quantitative performance as an alternative technology, several measurement tests and comparison test with INVS were conducted using ASAS. In these tests, evaluation of fundamental performance (counting efficiency and die-away time) and uncertainty evaluations were implemented. As a result, although fundamental performance of ASAS was not achieved to the one of INVS, we could confirm that ASAS has almost the same Pu quantitative performance including measurement uncertainty as that of INVS.
Mukai, Yasunobu; Nakamura, Hironobu; Tanigawa, Masafumi; Nakamichi, Hideo; Umino, Yoshinori; Fujisaku, Sakae; Kimura, Takashi; Kurita, Tsutomu
Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-36-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2015/12
When the unauthorized removal of nuclear materials (NM) from glovebox (GB) by an insider happens, it needs to be detected and reported immediately. In this time, for utilization of the security counterplan, the feasibility of a new detection concept for the unauthorized removal was investigated with implementation of several experiments considering actual GB operation. In general, the detection method using radiation monitor is thought of easily. However, it is very difficult to distinguish between authorized NM movement during operation and the unauthorized removal. To solve this subject, JAEA focused on negative pressure monitoring of GB, and investigated a new detection concept combining the neutron and negative pressure monitoring. As a result of the experiments in small-scale GB, it was revealed that this new concept had the capability to detect the unauthorized removal and to alarm to central alarm station rapidly, and had the possibility to enhance the effectiveness of the current physical protection measures.
LaFleur, A. M.*; Nakamura, Hironobu; Menlove, H. O.*; Mukai, Yasunobu; Swinhoe, M. T.*; Marlow, J. B.*; Kurita, Tsutomu
Proceedings of 37th ESARDA Annual Meeting (Internet), p.435 - 441, 2015/08
The IBAS (Improved Holdup Blender Assay System) system for safeguards and nuclear material accountancy (NMA) of holdup measurements is used at PCDF. The purpose of this detector is to measure the doubles rate from each glovebox in order to determine the mass of Pu holdup. In order to establish calibration curves for the IBAS detector and improve the holdup measurement methodology, JAEA conducted the IBAS calibration exercise with LANL support using MOX standards in 2010. In 2011, a cleanout exercise was performed and the results showed that the holdup removed from the glovebox had a significantly higher alpha term (alpha = 15.8 - 31.5) than the MOX standards (alpha = 0.67) used to establish the 2010 calibration curves. To further investigate these findings, JAEA conducted slope validation measurements in 2013 to confirm the validity of IBAS calibration slopes for the case of high alpha holdup. This paper describes the IBAS slope validation tests, analysis of the experimental results, and the evaluation of the need for a correction factor for the high alpha holdup. Quantifying the alpha term of the holdup in each glove box and understanding how this value changes over time is important to improving the overall NMA at PCDF. The results from this work will provide invaluable experimental data that directly supports safeguards and NMA measurements of plutonium holdup in gloveboxes.
Nakamura, Hironobu; Mukai, Yasunobu; Tobita, Hiroshi; Nakamichi, Hideo; Ozu, Akira; Kureta, Masatoshi; Kurita, Tsutomu; Seya, Michio
Proceedings of 37th ESARDA Annual Meeting (Internet), p.45 - 53, 2015/08
JAEA conducted an R&D project to develop a new type of neutron detector using ZnS/BO ceramic scintillator (as an alternative neutron detector to He-3) with support of Japanese government. The design of the JAEAs alternative system (ASAS: Alternative Sample Assay System using ceramic scintillator tubes) refers basically to the INVS (INVentory Sample assay system) which is the passive type of neutron assay system equipped total 18 He-3 tubes and capable of measuring the small amount of Pu in the MOX powder or Pu nitrate solution in a vial for nuclear material accountancy and safeguards verification. In order to prove the alternative technology and the performance instead of He-3 detector, and to establish Pu measurement capability, JAEA developed and fabricated ASAS equipped 24 alternative ceramic scintillator tubes (which is equivalent to the same counting efficiency of INVS) and demonstrated. The demonstration activity implemented the confirmation of reproducibility about sample positioning, optimization of detector parameters, counting statistical uncertainty, stability check and figure of merit (FOM) using Cf check source and actual MOX powder in PCDF (Plutonium Conversion Development Facility). In addition, performance comparison between the current INVS and the ASAS was also implemented. In this paper, we present demonstration results with design information with Monte-Carlo simulation code (MCNP).
Nakamura, Hironobu; Tanigawa, Masafumi; Mukai, Yasunobu; Nakamichi, Hideo; Umino, Yoshinori; Fujisaku, Sakae; Kimura, Takashi; Kurita, Tsutomu
Proceedings of INMM 56th Annual Meeting (Internet), 8 Pages, 2015/07
In the MOX handling facilities, many types and amount of nuclear materials (NM) that are relatively easy to access are used in a GB. In order to prevent unauthorized removal of NM from the GB by an insider, based on the Japanese regulation which was referred from INFCIRC/225 Rev.5, the 2 person rule are being introduced at the area where NM handling GB are installed. As an example of usage of the security counterplan for the detection of unauthorized removal of NM, a new proposal of detection concept for the unauthorized removal by operators were investigated with implementation of several experiments considering actual GB operation. In general, it is considered that normal concept is to use radiation monitor ( or neutron) to detect the event by checking the variation of monitoring data. However, it is thought that distinguish between authorized NM movement during operation and the unauthorized removal (sample bag-out from GB) is very difficult. To solve this subject, JAEA studied and proposes a new concept about negative pressure monitoring in the GB in addition to the radiation monitoring. It is thought that the hybrid monitoring concept between pressure and radiation provides the detection alarm for it with central alarm station (CAS) accurately and rapidly with high integrity, and helps to complement current 2 person rule.
Mukai, Yasunobu; Nakamura, Hironobu; Nakamichi, Hideo; Kurita, Tsutomu; Noguchi, Yoshihiko*; Tamura, Takayuki*; Ikegame, Ko*; Shimizu, Junji*
Proceedings of INMM 56th Annual Meeting (Internet), 9 Pages, 2015/07
The PIMS used at Rokkasho Reprocessing Plant can quantify plutonium amount in each process vessel located inside glovebox by means of neutron measurement. Since the PIMS is not used for the neutron coincidence counting, it is very important to maintain that those constants meet the actual process condition. PIMS was calibrated in 2006, and then JNFL has been started to measure the Pu amount directly in each glovebox for the purpose of facility NMA. However, it was found that PIMS counting was unexpectedly and continuously increased during long time of inter-campaign. In order to find out the main cause, JAEA and JNFL jointly conducted several investigations. In the investigations, correctness of system parameters and relevant constants, behavior of the neutron generation when MOX powder is stored in actual glovebox for a long time (to see O/M and moisture change) and the behavior focused on the relation between MOX powder and light element using inside glovebox (fluorine is included in the PTFE which is used in many gloveboxes as packing of instruments) were experimentally confirmed using MOX powder in PCDF. As a result, since the same behavior happened in the actual PIMS was confirmed in the testing environment in which MOX powder coexists with fluorine, it is concluded that the main potential cause of PIMS is the increasing of the probability of (
, 
) reactions by a contact between PTFE and MOX powder.
Nakamura, Hironobu; Mukai, Yasunobu; Kurita, Tsutomu
Book of Abstracts, Presentations and Papers of Symposium on International Safeguards; Linking Strategy, Implementation and People (Internet), 8 Pages, 2015/03
The Distributed Source-Term Analysis (DSTA) technique has been used in a variety of safeguards applications to determine location and quantity of material contained within large sample volumes. By applying this method, JAEA developed and applied two different neutron measurement techniques in order to improve own MC&A. The first advanced technique is a Glove Box Cleanout Assistance Tool (BCAT). It is used by operator during cleanout just before PIT to increase recovered material, to decrease unmeasured inventory, and to perform the cleanout activity effectively. The BCAT is being introduced to the actual cleanout since 2011. The second advanced technique is a dynamic cross-talk correction (DCTC) method. The DCTC can obtain actual doubles signal cross-talk between multiple gloveboxes. In order to assay Pu amount in the holdup correctly, we implemented an improved HBAS system using DCTC. Two advanced holdup measurement technologies provide appropriate safety and safeguards environment to conduct nuclear cycle with operator and inspector.
BO ceramic scintillator detectorsNakamura, Hironobu; Ozu, Akira; Kobayashi, Nozomi*; Mukai, Yasunobu; Sakasai, Kaoru; Nakamura, Tatsuya; Soyama, Kazuhiko; Kureta, Masatoshi; Kurita, Tsutomu; Seya, Michio
Proceedings of INMM 55th Annual Meeting (Internet), 9 Pages, 2014/07
To establish an alternative technique of He-3 neutron detector that is used for nuclear material accountancy and safeguards, we have started an R&D project to develop a new type of neutron detector (Pu NDA system) using ZnS/BO ceramic scintillator with support of Japanese government. The design of the alternative system (ASAS: Alternative Sample Assay System) is basically referenced from INVS (INVentory Sample assay system) which is passive neutron assay system of plutonium and has total 18 He-3 tubes (about 42% of counting efficiency), and the small amount of Pu in the MOX powder or Pu nitrate solution in a vial can be measured. In order to establish the technology and performance after the fabrication of the new detector progresses, we are planning to conduct demonstration activity in the early 2015 experimentally. The demonstration activity implements the confirmation of reproducibility about sample positioning, optimization of detector parameters, counting statistical uncertainty, stability (temperature and -ray change) check and figure of merit (FOM) using check source and actual MOX powder. In addition to that, performance comparison between current INVS and the ASAS are also conducted. In this paper, we present some analytical study results using a Monte-Carlo simulation code (MCNP), entire ASAS design and demonstration plan to prove technology and performance.
B+He integrated continuous monitor (BHCM) to holdup monitoring in glove boxesMukai, Yasunobu; LaFleur, A. M.*; Nakamura, Hironobu; Menlove, H. O.*; Swinhoe, M. T.*; Marlow, J. B.*; Kurita, Tsutomu
Proceedings of INMM 55th Annual Meeting (Internet), 8 Pages, 2014/07
In order to improve the safeguards and nuclear material accountancy of holdup measurements and establish an alternative technology for He shortage, we have designed the B + He Integrated Continuous Monitor (BHCM) and implemented the measurements to continuously monitor the holup in gloveboxes at Plutonium Conversion Developoment Facility. In this paper, we present the outline of BHCM, the comparison between MCNP simulations and the measured results in preliminaly test and a demonstration of process monitoring ability during operation to see the relation between Totals trend and operational status by using B detection tubes.
Ozu, Akira; Kureta, Masatoshi; Haruyama, Mitsuo; Takase, Misao; Kurata, Noritaka; Kobayashi, Nozomi; Soyama, Kazuhiko; Nakamura, Tatsuya; Sakasai, Kaoru; To, Kentaro; et al.
Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-34-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2013/10
no abstracts in English
