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-ray spectroscopy combined with active neutron interrogation for nuclear security and safeguards小泉 光生; Rossi, F.; Rodriguez, D.; 高峰 潤; 瀬谷 道夫; Bogucarska, T.*; Crochemore, J.-M.*; Varasano, G.*; Abbas, K.*; Pedersen, B.*; et al.
EPJ Web of Conferences, 146, p.09018_1 - 09018_4, 2017/09
被引用回数：3 パーセンタイル：86.43(Nuclear Science & Technology)Along with the global increase of applications using nuclear materials (NM), the requirements to nuclear security and safeguards for the development of effective characterization methods are growing. Mass verification of NM of low radioactivity is performed using passive non-destructive analysis (NDA) techniques whereas destructive analysis (DA) techniques are applied for accurate analysis of nuclide composition. In addition to the characterization by passive NDA, a sample can be further characterized by active NDA techniques. An active neutron NDA system equipped with a pulsed neutron generator is currently under development for studies of NDA methods. Among the methods DGS uses the detection of decay -rays from fission products (FP) to determine ratios of fissile nuclides present in the sample. A proper evaluation of such -ray spectra requires integration of nuclear data such as fission cross-sections, fission yields, half-lives, decay chain patterns, and decay -ray emission probabilities. The development of the DGS technique includes experimental verification of some nuclear data of fissile materials, as well as development of the device. This presentation will be a brief introduction of the active neutron NDA project and an explanation of the DGS development program.
-ray spectrometer for detecting 
B in debris of melted nuclear fuel小泉 光生; 土屋 晴文; 北谷 文人; 原田 秀郎; Heyse, J.*; Kopecky, S.*; Mondelaers, W.*; Paradela, C.*; Schillebeeckx, P.*
Nuclear Instruments and Methods in Physics Research A, 837, p.153 - 160, 2016/11
被引用回数：2 パーセンタイル：19.71(Instruments & Instrumentation)Neutron Resonance Densitometry (NRD) has been proposed as a non-destructive analytical method for quantifying Special Nuclear Material (SNM) in the rock- and particle-like debris that is to be removed from the Fukushima Daiichi Nuclear Power Plant. The method is based on Neutron Resonance Transmission Analysis (NRTA) and Neutron Resonance Capture Analysis combined with Prompt Gamma Ray Analysis (NRCA/PGA). Although quantification of SNM will predominantly rely on NRTA, this will be hampered by the presence of strong neutron-absorbing matrix materials, in particular B. Results obtained with NRCA/PGA are used to improve the interpretation of NRTA data. Prompt -rays originating from the B(n, 
) reaction are used to assess the amount of B. The 478 keV -rays from B, however, need to be measured under a high-radiation environment, especially from 
Cs. In order to meet this requirement, we have developed a well-shaped -ray spectrometer consisting of a cylindrical and four rectangular cuboid LaBr scintillators, and a fast data acquisition system.
小泉 光生; Heyse, J.*; Mondelaers, W.*; Paradela, C.*; Pedersen, B.*; Schillebeeckx, P.*; 瀬谷 道夫; Rodriguez, D.; 高峰 潤
核物質管理学会(INMM)日本支部第36回年次大会論文集(インターネット), 6 Pages, 2015/12
核分裂生成物の構成(分布)は、元となる核分裂性核種と照射中性子エネルギーにより異なってくる。それゆえ、核分裂生成物収率の違いによる遅発線(DG)スペクトルの違いから、核分裂性核種(
U, 
Pu及び
Pu)の比が求められる。このDGS法プロジェクトは、核データの確認と改良を行いつつ実施する測定システムに関する研究開発である。実験に関しては、中性子源と核物質が取り扱えるITU/Ispra(イタリア), IRMM(ベルギー),京都大学研究用原子炉(熊取)などの施設を用いて実施する予定である。本発表では、現在計画しているDGS法の開発実験について報告する。
原田 秀郎; 木村 敦; 北谷 文人; 小泉 光生; 土屋 晴文; Becker, B.*; Kopecky, S.*; Schillebeeckx, P.*
Journal of Nuclear Science and Technology, 52(6), p.837 - 843, 2015/06
被引用回数：3 パーセンタイル：25.85(Nuclear Science & Technology)Neutron resonance densitometry (NRD) is a non-destructive analysis method, which can be applied to quantify special nuclear materials (SNM) in small particle-like debris of melted fuel that is formed in severe accidents of nuclear reactors such as the Fukushima Daiichi Nuclear Power Plants. NRD uses neutron resonance transmission analysis (NRTA) to quantify SNM and neutron resonance capture analysis (NRCA) to identify matrix materials and impurities. In order to generalize NRD for the characterization of arbitrary-shaped thick materials, a generalized method to analyze NRTA data has been developed. The method has been applied on data resulting from transmission through non-uniform thick samples with varying areal density of SNM up to 0.253 at/b (
100 g/cm
). The investigation shows that NRD could be used to quantify SNM in not only uniform samples made of small particle-like debris but also non-uniform samples made of large rock-like debris with high accuracy by utilizing the generalized analysis method for NRTA.
シンチレーション検出装置の開発小泉 光生; 土屋 晴文; 北谷 文人; 原田 秀郎; 高峰 潤; 呉田 昌俊; 瀬谷 道夫; 木村 敦; 飯村 秀紀; Becker, B.*; et al.
核物質管理学会(INMM)日本支部第35回年次大会論文集(インターネット), 8 Pages, 2015/01
粒子状デブリ中の核物質を定量するため、中性子共鳴濃度分析法(neutron resonance densitometry: NRD)を開発している。これは、中性子共鳴透過分析法(NRTA)と、中性子共鳴捕獲分析法(NRCA)または即発線分析法(PGA)の2つの手法を組み合わせたものである。NRCA/PGAは、NRTAでは測定が難しい混入物の同定を行う。中性子捕獲線を測定するために、LaBr検出器で構成されるスペクトロメータを開発している。導入したデータ収集系は、500kイベント/秒の信号を8チャンネルで扱うことができる。本講演では、NRDの研究開発状況ならびにスペクトロメータシステムの開発状況について発表する。
Schillebeeckx, P.*; Becker, B.*; 原田 秀郎; Kopecky, S.*
Landolt-B
rnstein Group 1, Vol.26; Numerical Data and Functional Relationships in Science and Technology, Subv.A; Neutron Resonance Parameters, p.4 - 52, 2015/00
中性子と原子核が反応する確率は、入射中性子のエネルギーに大きく依存し、多くの原子核で中性子共鳴が現れる。この性質を利用した非破壊分析法として、中性子共鳴透過分析法と中性子共鳴捕獲線分光法がある。本報告では、各分析法の原理を解説すると共に、両手法の利点を組み合わせた新たな非破壊分析法として開発を進めている中性子共鳴濃度分析法について解説する。
小泉 光生; 北谷 文人; 土屋 晴文; 原田 秀郎; 高峰 潤; 呉田 昌俊; 飯村 秀紀; 瀬谷 道夫; Becker, B.*; Kopecky, S.*; et al.
Nuclear Back-end and Transmutation Technology for Waste Disposal, p.13 - 20, 2015/00
溶融燃料中の核物質の計量管理するための技術として、中性子共鳴濃度分析法(Neutron Resonance Densitometry (NRD))を提案している。この手法は、Neutron Resonance Transmission Analysis(NRTA)とNeutron Resonance Capture Analysis (NRCA)もしくはPrompt Gamma ray Analysis (PGA)の2つの手法を組み合わせたもので、パルス中性子源を装備した飛行時間(TOF)測定装置を用いる。この測定法を確立するために、検出器の開発を進めるとともに、EC-JRC-IRMMのGELINA TOF実験施設で、共同研究を進めている。研究進捗について、総括的に報告する。
土屋 晴文; 原田 秀郎; 小泉 光生; 北谷 文人; 高峰 潤; 呉田 昌俊; 飯村 秀紀; 木村 敦; Becker, B.*; Kopecky, S.*; et al.
Proceedings of INMM 55th Annual Meeting (Internet), 6 Pages, 2014/07
Neutron resonance densitometry (NRD) is based on a combination of neutron resonance transmission analysis (NRTA) and neutron resonance capture analysis (NRCA). This technique is a non-destructive method to quantify nuclear materials in particle-like debris of melted fuel that is generated by a severe accident like the one at the Fukushima Daiichi Nuclear Power Plant. To verify the effectiveness of NRD, the Japan Atomic Energy Agency (JAEA) and the Joint Research Center, Institute for Reference Materials and Measurements (EC-JRC-IRMM) started collaboration in 2012. One of the main objectives of this collaboration is to quantitatively investigate all uncertainty components on results of NRD measurements. Clearly, systematic effects due to the characteristics of samples such as the sample inhomogeneity, presence of impurities, radioactivity and temperature have a strong impact on the accuracy. To study the uncertainty due to the sample characteristics, NRTA and NRCA experiments are in progress at the time-of-flight facility GELINA (Geel Electron LINear Accelerator) of the EC-JRC-IRMM. In this presentation, we show results considering mixed sample effect on NRTA measurements. Data are analyzed with the resonance shape analysis code REFIT to derive the elemental composition of the sample and the areal density of the main components. In addition the effect of neutron absorbing matrix material will be discussed.
scintillation detector system for neutron resonance densitometry (NRD)小泉 光生; 土屋 晴文; 北谷 文人; 原田 秀郎; 高峰 潤; 呉田 昌俊; 瀬谷 道夫; 木村 敦; 飯村 秀紀; Becker, B.*; et al.
Proceedings of INMM 55th Annual Meeting (Internet), 7 Pages, 2014/07
Neutron resonance densitometry (NRD) has been proposed as a method to quantify the amount of special nuclear materials in particle-like debris of melted fuel. The requirements of a -ray detector system for the NRD measurements are: (1) good energy resolution to identify elements (2) fast response not to be suffocated by the radiation from debris samples and (3) good signal to noise ratio. The quantification of B is considered to be the most important for NRD because of its very large neutron cross-sections. However, the Compton peak of the rays from Cs, which is probably the strongest radioactivity in debris, overlaps the B peak; and it makes the measurements difficult. We, therefore, designed a well-type LaBr scintillation spectrometer to reduce the Compton peak. The progress of the research and development of the spectrometer is reported.
原田 秀郎; Schillebeeckx, P.*; 土屋 晴文; 北谷 文人; 小泉 光生; 高峰 潤; 呉田 昌俊; 飯村 秀紀; 木村 敦; 瀬谷 道夫; et al.
Proceedings of INMM 55th Annual Meeting (Internet), 8 Pages, 2014/07
Neutron resonance densitometry (NRD) has been developed to quantify nuclear materials in particle-like debris of melted fuel formed in severe accidents of nuclear reactors such as Fukushima Daiichi Nuclear Power Plants. NRD is a method combining NRTA (neutron resonance transmission analysis) and NRCA (neutron resonance capture analysis). It relies on neutron TOF technique using a pulsed white neutron source. A specially designed -ray spectrometer for NRCA has been developed for the characterization of contamination materials mixed with nuclear fuel materials. Achievable accuracy is studied based on Monte Carlo simulations and experimental data measured at the time-of-flight facility GELINA of the EC-JRC-IRMM. Analysis method of NRTA for particle-like debris has been developed by adding a function in a resonance analysis code REFIT. In this contribution, these achievements on NRD for the characterization of nuclear materials mixed with highly radioactive nuclides are reviewed, and its applicability is discussed.
原田 秀郎; 北谷 文人; 小泉 光生; 高峰 潤; 呉田 昌俊; 土屋 晴文; 飯村 秀紀; 瀬谷 道夫; Becker, B.*; Kopecky, S.*; et al.
Nuclear Data Sheets, 118, p.502 - 504, 2014/04
被引用回数：4 パーセンタイル：32.98(Physics, Nuclear)Feasibility study of neutron resonance densitometry (NRD) has been started to quantify of nuclear materials in particle-like debris of melted fuel formed in severe accidents of nuclear reactor such as Fukushima Daiichi Nuclear Power Plants. The NRD here is a combined method of NRTA (neutron resonance transmission analysis) and NRCA (neutron resonance capture analysis) using a pulsed neutron generator and TOF (time of flight) measurement. The presentation includes the proposed compact NRD system, the spectrometer design for NRCA using LaBr detectors by Monte Carlo simulations, and analytical studies on achievable accuracies. The experimental results using particle-like Cu samples measured at the GELINA facility in IRMM are also shown in comparison with analytical studies. Required nuclear data for the NRD will be also discussed.
原田 秀郎; 北谷 文人; 小泉 光生; 土屋 晴文; 高峰 潤; 呉田 昌俊; 飯村 秀紀; 瀬谷 道夫; Becker, B.*; Kopecky, S.*; et al.
Proceedings of INMM 54th Annual Meeting (CD-ROM), 10 Pages, 2013/07
粒子状溶融燃料に含有される核燃料を計量するために機構が開発を進めている中性子共鳴濃度分析法の技術開発の進捗について、測定原理の他、含有されるボロン等の不純物を分析するために特別に設計した線検出器の評価、IRMMのパルス中性子発生施設GELINAで実施した試験研究の成果、及びプロトタイプ装置の設計を含め、総括的に報告する。
原田 秀郎; 北谷 文人; 小泉 光生; 土屋 晴文; 高峰 潤; 呉田 昌俊; 飯村 秀紀; 瀬谷 道夫; Becker, B.*; Kopecky, S.*; et al.
Proceedings of 35th ESARDA Annual Meeting (Internet), 6 Pages, 2013/05
福島第一原子力発電所のような原子炉事故で発生すると考えられる粒子状溶融燃料中の核物質量を精度よく非破壊で計量するため、パルス中性子源を利用した中性子共鳴濃度分析法(Neutron Resonance Densitometry: NRD)を提案した。NRDは、中性子共鳴透過分析法(Neutron Resonance Transmission Analysis: NRTA)と中性子共鳴捕獲分析法(Neutron Resonance Capture Analysis: NRCA)を組合せた分析法である。本手法の分析原理、予備解析による測定精度及び開発計画について講演する。
Becker, B.*; 原田 秀郎; Kauwenberghs, K.*; 北谷 文人; 小泉 光生; Kopecky, S.*; Moens, A.*; Schillebeeckx, P.*; Sibbens, G.*; 土屋 晴文
Proceedings of 35th ESARDA Annual Meeting (Internet), 7 Pages, 2013/05
Neutron Resonance Densitometry (NRD) represents a possible option to determine the heavy metal content in melted nuclear fuel. It is a non-destructive method and is applicable for highly radioactive material. The accuracy of NRD depends among other factors on sample characteristics. Inhomogeneities such as density variations in powder samples can introduce a significant bias in the determination of the composition. In this contribution, the impact of the particle size distribution of such powder samples on results obtained with NRD is investigated. Various analytical models, describing the neutron transport through powder, are compared. Stochastic numerical simulations are used to select a specific model and to estimate the introduced model uncertainty. The results from these simulations will be verified by dedicated measurements at the TOF-facility GELINA of the EC-JRC-IRMM.
Schillebeeckx, P.*; Abousahl, S.*; Becker, B.*; Borella, A.*; Emiliani, F.*; 原田 秀郎; Kauwenberghs, K.*; 北谷 文人; 小泉 光生; Kopecky, S.*; et al.
Proceedings of 35th ESARDA Annual Meeting (Internet), 11 Pages, 2013/05
Neutron Resonance Capture Analysis (NRCA) and Neutron Resonance Transmission Analysis (NRTA) have been applied to determine the elemental composition of archaeological objects and to characterize nuclear reference materials. A combination of NRTA and NRCA, referred to as Neutron Resonance Densitometry (NRD), is being studied as a non-destructive method to characterize particle-like debris of melted fuel that is formed in severe nuclear accidents such as the one which occurred at the Fukushima Daiichi Nuclear Power Plants. This study is part of a collaboration between JAEA and EC-JRC-IRMM. In this contribution the basic principles of NRTA and NRCA are explained based on the experience in the use of these methods at the time-of-flight facility GELINA of the EC-JRC-IRMM. Specific problems related to the analysis of samples resulting from melted fuel are discussed. The programme to study and solve these problems is described and results of a first measurement campaign at GELINA are given.
