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Journal Articles

Utilizing PUNITA experiments to evaluate fundamental delayed gamma-ray spectroscopy interrogation requirements for nuclear safeguards

Rodriguez, D.; Koizumi, Mitsuo; Rossi, F.; Seya, Michio; Takahashi, Toon; Bogucarska, T.*; Crochemore, J.-M.*; Pedersen, B.*; Takamine, Jun

Journal of Nuclear Science and Technology, 57(8), p.975 - 988, 2020/08

Journal Articles

Proliferation resistance evaluation of an HTGR transuranic fuel cycle using PRAETOR code

Aoki, Takeshi; Chirayath, S. S.*; Sagara, Hiroshi*

Annals of Nuclear Energy, 141, p.107325_1 - 107325_7, 2020/06

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

The proliferation resistance (PR) of an inert matrix fuel (IMF) in the transuranic nuclear fuel cycle (NFC) of a high temperature gas cooled reactor is evaluated relative to the uranium and plutonium mixed-oxide (MOX) NFC of a light water reactor using PRAETOR code and sixty-eight input attributes. The objective is to determine the impacts of chemical stability of IMF and fuel irradiation on the PR. Specific material properties of the IMF, such as lower plutonium content, carbide ceramics coating, and absence of $$^{235}$$U, contribute to enhance its relative PR compared to MOX fuel. The overall PR value of the fresh IMF (an unirradiated direct use material with a one-month diversion detection timeliness goal) is nearly equal to that of the spent MOX fuel (an irradiated direct use nuclear material with a three-month diversion detection timeliness goal). Final results suggest a reduced safeguards inspection frequency to manage the IMF.

Journal Articles

Model design of a compact delayed gamma-ray moderator system using $$^{252}$$Cf for safeguards verification measurements

Rodriguez, D.; Rossi, F.; Takahashi, Toon; Seya, Michio; Koizumi, Mitsuo

Applied Radiation and Isotopes, 148, p.114 - 125, 2019/06

 Times Cited Count:3 Percentile:31.52(Chemistry, Inorganic & Nuclear)

Journal Articles

Delayed gamma-ray spectroscopy, 2; Design study of moderator for a practical system

Rossi, F.; Rodriguez, D.; Takahashi, Toon; Seya, Michio; Koizumi, Mitsuo

Nihon Kaku Busshitsu Kanri Gakkai Dai-39-Kai Nenji Taikai Rombunshu (CD-ROM), 3 Pages, 2018/11

This paper (presentation) reports on the design study for seeking compactness of moderator (and reflector) structure for the Delayed Gamma-ray Spectroscopy Non Destructive Assay system to be applied for verification of fissile isotopic (Pu-239, Pu-241 and U-235) composition ratio in High Radioactive Nuclear Material sample such as dissolved solution of reprocessing facility. We first investigated advantages and disadvantages of using different compact neutron sources as DT and DD neutron generators. This led us to the conclusion of using DD sources to achieve a compact (and practical) NDA system. Based on MCNP simulations, with the use of a DD neutron generator, a preliminary optimization study was performed and will be shown here.

Journal Articles

Delayed gamma-ray spectroscopy inverse Monte Carlo analysis method for nuclear safeguards nondestructive assay applications

Rodriguez, D.; Rossi, F.; Seya, Michio; Koizumi, Mitsuo

Proceedings of 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2017) (Internet), 3 Pages, 2018/11

Journal Articles

Demonstration of $$gamma$$-ray pipe-monitoring capabilities for real-time process monitoring safeguards applications in reprocessing facilities

Rodriguez, 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:100(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 $$gamma$$ 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 $$gamma$$ ray pipe-monitoring method using plutonium-nitrate solution transferred between tanks at the PCDF-TRP. The $$gamma$$ rays were measured using a lanthanum-bromide detector with a list-mode data acquisition system to obtain both time and energy of $$gamma$$-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.

Journal Articles

Development of delayed gamma-ray spectroscopy for nuclear material analysis

Rodriguez, D.; Rossi, F.; Takahashi, Toon; Seya, Michio; Koizumi, Mitsuo; Crochemore, J. M.*; Varasano, G.*; Bogucarska, T.*; Abbas, K.*; Pedersen, B.*

Proceedings of INMM 59th Annual Meeting (Internet), 7 Pages, 2018/07

Journal Articles

Integrated risk assessment of safety, security, and safeguards

Suzuki, Mitsutoshi

Risk Assessment, p.133 - 151, 2018/02

A integrated risk assessment could be developed to promote synergism between safety, security, and safeguards (3S). One of the synergies of the integrated 3S risk assessment is a 3S by Design approach for new nuclear facilities. In safety, the classical probabilistic risk assessment (PRA) has been developed to estimate the frequency of severe accident using the basic event frequency. Because of recent concern about nuclear security, a vital area identification method based on the ETs/FTs has been explored to protect vital areas of nuclear power plants against sabotage. The different difficulty in applying risk assessment to safeguards is determining the initiation of diversion of nuclear material and misuse, because the diversion of nuclear material and misuse of technology are induced by the motivation of states and intentional acts of facility operation. In this chapter, a balance among 3S risk would be explored to pursue an optimal and a cost-effective management.

Journal Articles

Neutron resonance analysis for nuclear safeguards and security applications

Paradela, C.*; Heyse, J.*; Kopecky, S.*; Schillebeeckx, P.*; Harada, Hideo; Kitatani, Fumito; Koizumi, Mitsuo; Tsuchiya, Harufumi

EPJ Web of Conferences, 146, p.09002_1 - 09002_4, 2017/09

 Times Cited Count:3 Percentile:4.51

JAEA Reports

Application of probability generating function to the essentials of nondestructive nuclear materials assay system using neutron correlation

Hosoma, Takashi

JAEA-Research 2016-019, 53 Pages, 2017/01

JAEA-Research-2016-019.pdf:5.71MB

Application of probability generating function for nondestructive nuclear materials assay system was studied. First, high-order neutron correlations were derived algebraically up to septuplet and basic characteristics of the correlations were investigated. It was found that higher-order correlation increases rapidly in response to the increase of leakage multiplication, crosses and leaves lower-order correlations behind, when leakage multiplication is $$>$$ 1.3 that depends on detector efficiency and counter setting. Next, fission rates and doubles count rates by fast neutron and by thermal neutron in their coexisting system were derived algebraically. It was found that the number of induced fissions per unit time by fast neutron and by thermal neutron, the number of induced fissions ($$<$$ 1) by one source neutron, and individual doubles count rates were possible to be estimated from Rossi-alpha combined distribution and measured ratio of each area obtained by differential die-away self-interrogation and conventional assay data.

Journal Articles

JAEA's contribution for R&D and human resource development on implementing IAEA safeguards

Naoi, Yosuke; Oda, Tetsuzo; Tomikawa, Hirofumi

Nippon Genshiryoku Gakkai-Shi, 58(9), p.536 - 541, 2016/09

Japan has been promoting nuclear energy research and development, and the use of nuclear energy for only peaceful purposes in accordance with Atomic Energy Basic Acts enacted in 1955. In order to ensure limited to their peaceful utilization, it has been performing a nuclear material accountancy and reporting it based on bilateral nuclear agreement (Japan and the United States, Japan and France, Japan and Canada and so on) before concluding the comprehensive safeguards agreement with the IAEA. After the conclusion of that in 1977, the Japanese national law had been revised. The nuclear material accountancy and its reports to the IAEA have been implemented based on the revised law. In 1999, Japan ratified the additional protocol. Then it has been responding a new obligation in the additional protocol. The correctness and completeness of the declaration of nuclear activities in Japan have been verified by the IAEA, and then the "broader conclusion" was given to Japan in 2004. There indicates no diversion or undeclared nuclear activities in Japan. Since then Japan has been obtaining the "broader conclusion" every year. In this report we will report the JAEA's contribution to the IAEA safeguards on technical research and development and human resource development.

Journal Articles

Operator's contribution on the improvement of RII scheme against the process operation at PCDF

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.

Journal Articles

Uranium particle identification with SEM-EDX for isotopic analysis by secondary ion mass spectrometry

Esaka, Fumitaka; Magara, Masaaki

Mass Spectrometry Letters, 7(2), p.41 - 44, 2016/06

Secondary ion mass spectrometry (SIMS) is a promising tool to measure isotope ratios of individual uranium particles in environmental samples for nuclear safeguards. However, the analysis requires prior identification of a small number of uranium particles that coexist with a large number of other particles without uranium. In the present study, this identification was performed by scanning electron microscopy -energy dispersive X-ray analysis with automated particle search mode. The analytical results for an environmental sample taken at a nuclear facility indicated that the observation of backscattered electron images with $$times$$ 1000 magnification was appropriate to efficiently identify uranium particles. Lower magnification (less than $$times$$ 500) made it difficult to detect smaller particles of approximately 1 $$mu$$m diameter.

Journal Articles

Application of automated particle screening for effective analysis of individual uranium particles by thermal ionization mass spectrometry

Esaka, Fumitaka; Suzuki, Daisuke; Yomogida, Takumi; Magara, Masaaki

Analytical Methods, 8(7), p.1543 - 1548, 2016/02

AA2015-0572.pdf:0.66MB

 Times Cited Count:6 Percentile:41.92(Chemistry, Analytical)

The isotope ratio analysis of individual uranium particles in environmental samples taken at nuclear facilities is important to clarify their origins for nuclear safeguards. In the present study, automated particle screening was used to select uranium particles prior to precise isotope ratio analysis by thermal ionization mass spectrometry (TIMS). As a result, molecular ion interferences on the uranium mass region were able to be almost completely avoided in the analysis of real inspection samples using APM-TIMS. Therefore, the performance of APM-TIMS was sufficient for obtaining isotope ratio data of individual particles without molecular ion interferences.

JAEA Reports

The States of the art of the nondestructive assay of spent nuclear fuel assemblies; A Critical review of the Spent Fuel NDA Project of the U.S. Department of Energy's Next Generation Safeguards Initiative

Bolind, A. M.*; Seya, Michio

JAEA-Review 2015-027, 233 Pages, 2015/12

JAEA-Review-2015-027.pdf:30.21MB

This report surveys the 14 advanced NDA techniques that were examined by the Spent Fuel NDA Project of the Next Generation Safeguards Initiative (NGSI) of the U.S. DOE-NNSA. It discusses and critique NDA techniques from a view point of obtaining higher accuracies. The report shows the main problem, large uncertainties in the assay results are caused primarily by using too few independent NDAs. In this report authors shows that at least three independent NDA techniques are required for obtaining better accuracies, since the physics of the NDA of SFAs is three dimensional.

JAEA Reports

Essentials of neutron multiplicity counting mathematics; An Example of U-Pu mixed dioxide

Hosoma, Takashi

JAEA-Research 2015-009, 162 Pages, 2015/08

JAEA-Research-2015-009.pdf:22.3MB

Neutron coincidence counting assay systems have been developed in the last two decades. Objects would extend to high-mass uranium-plutonium dioxide containing other spontaneous fission nuclei, so essentials of neutron multiplicity counting were reconsidered and expanded: (a) Formulae of multiplicity distribution were algebraically derived up to septuplet using a probability generating function; (b) Leakage multiplication was evaluated not by Monte Carlo method but by an average length from an arbitrary point inside a sample to an arbitrary point on its surface and a probability of induced fission within the length; (c) Mechanism of coincidence counting was associated with a couple of different time axes in Poisson process, and consequently a pair of close-to-coincident neutrons from the process was derived. For the formulae, new expressions using combination were wrote down. For spectrum and mean free path, actually treated uranium-plutonium dioxide was selected as an example.

Journal Articles

Utilizing delayed $$gamma$$ rays for fissionable material measurement in NDA

Rodriguez, D.; Takamine, Jun; Koizumi, Mitsuo; Seya, Michio

Proceedings of 37th ESARDA Annual Meeting (Internet), p.831 - 836, 2015/08

A non-destructive analysis system using a pulsed neutron source is under design by researchers of the JAEA, and JRC-ITU (Ispra) and JRC-IRMM. The system will utilize a combination of neutron resonance transmission analysis and differential die-away and both prompt and Delayed Gamma-ray (DG) Spectroscopy (DGS) techniques. This system will be applied toward safeguards applications by effectively determining Nuclear Material (NM) compositions within MOX fuel samples and NM samples with high neutron or $$gamma$$-ray emissions (including the melted fuel). Additionally, this system can be applied toward nuclear security by detecting the high-energy DGs that can more efficiently pass through shielding materials. This presentation will describe the initial status of the DG portion of this system and how it will be used in conjunction with the other techniques to provide both high accuracy and high precision of the composition of the NM of interest.

Journal Articles

Current activities and future challenges of FNCA's nuclear security and safeguards project

Senzaki, Masao

Proceedings of INMM 56th Annual Meeting (Internet), 10 Pages, 2015/07

The presentation outlines the role and objectives of Nuclear Security and Safeguards Project (NSSP) as well as FNCA framework and provides activity examples of how NSSP member countries work together to strengthen nuclear security and enhance safeguards effectiveness and raise awareness.

Journal Articles

Japan Atomic Energy Agency (JAEA)'s international capacity building regarding safeguards and SSAC; 20 years of achievement and future challenges

Senzaki, Masao; Naoi, Yosuke; Kuribayashi, Toshihiro; Hamada, Kazuko; Okumura, Yukiko

Proceedings of INMM 55th Annual Meeting (Internet), 10 Pages, 2014/07

JAEA has supported to HRD of mainly Asian countries in the field of SGs and SSAC, and works closely with governmental organizations in Japan, and with the IAEA, the U.S. DOE, EC, the flame work of FNCA, APSN. This paper presents the efforts, contributions and future challenges of JAEA to HRD regarding SGs and SSAC, through international cooperation, which have been taking place for around 20 years.

Journal Articles

Challenge to ultra-trace analytical techniques of nuclear materials in environmental samples for safeguards at JAERI; Methodologies for physical and chemical form estimation

Usuda, Shigekazu; Yasuda, Kenichiro; Kokubu, Yoko; Esaka, Fumitaka; Lee, C. G.; Magara, Masaaki; Sakurai, Satoshi; Watanabe, Kazuo; Hirayama, Fumio; Fukuyama, Hiroyasu; et al.

International Journal of Environmental Analytical Chemistry, 86(9), p.663 - 675, 2006/08

 Times Cited Count:13 Percentile:59(Chemistry, Analytical)

The IAEA introduced the environmental sample analysis method, as a powerful tool to detect undeclared nuclear activities, into strengthened safeguards system. The principle of the method is that nuclear signatures can be evidenced if trace amount of nuclear materials in environmental samples taken from inside and outside of nuclear facilities are accurately analyzed. Currently, isotope ratios of uranium and plutonium in "swipe" samples are measured, which are collected in nuclear facilities. In future, the subject of environmental sample analysis will expand to soil, sediment, vegetation, water and airborne dust taken from outside of the nuclear facilities. If physical and chemical form of the nuclear materials is identified, we may estimate their origin, treatment process and migration behavior. This paper deals with the developed analytical techniques for the safeguards environmental samples, the current R&D on techniques related to estimation of the physical and chemical form, and possible analytical methodologies applicable to ultra-trace amounts of nuclear materials.

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