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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

 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

Delayed $$gamma$$-ray spectroscopy combined with active neutron interrogation for nuclear security and safeguards

Koizumi, Mitsuo; Rossi, F.; Rodriguez, D.; Takamine, Jun; Seya, Michio; Bogucarska, T.*; Crochemore, J.-M.*; Varasano, G.*; Abbas, K.*; Pedersen, B.*; et al.

EPJ Web of Conferences (Internet), 146, p.09018_1 - 09018_4, 2017/09


Journal Articles

Delayed gamma-ray spectroscopy, 1; Development and current status

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

Proceedings of INMM 58th Annual Meeting (Internet), 6 Pages, 2017/07

The JAEA is collaborating with the EC-JRC to develop a NDA system combining four active techniques to improve safeguards verification. Delayed gamma-ray spectroscopy can determine nuclide ratios by correlating observed fission products' time-dependent, high-energy, $$gamma$$ rays to the sample's complex fission yield. To quantify fissile nuclides of significant interest, the fast neutrons from compact, transportable sources must be thermalized to where the fissile nuclides have large cross-sections while maintaining high fluxes to provide significant signals. Experiments are underway at some facilities to improve DGS, including the PUNITA system at JRC-Ispra. These neutron fluxes and measurement conditions are used to develop a Monte Carlo that will be used to analyze the DGS data by an inverse-MC method. The DGS program described here summarizes the 3-year development to optimize the moderator, perform experiments, and create the IMC in preparation for a demonstration of the technique.

Journal Articles

Delayed gamma-ray spectroscopy, 2; Experimental studies for determination of fissile materials ratios

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

Proceedings of INMM 58th Annual Meeting (Internet), 7 Pages, 2017/07

In the field of nuclear safeguards, new and improved active-interrogation NDA technologies are needed for the independent verification of the fissile composition in HRNM. JAEA and the JRC are now collaborating to develop DGS to determine ratios of fissile nuclides present in the sample measuring the decay gamma rays from FP. Measurements of LRNM samples are underway using different facilities. To minimize the interference from the LLFP, it is important to use shielding and to consider those gamma rays above 3-MeV. Different compact neutron sources are available, but all of them need to be slowed down to the thermal energy region. We are optimizing moderator and reflector materials using MCNP. Optimization of the irradiation, transfer and measurement sequence is now underway. The experiments we are conducting using certified mono-elemental U/Pu samples allow us to associate observed DG to the proportional isotopic compositions. In this paper we will present the current status of the optimization process and the experimental campaign for the determination of the ratio of fissile materials of U and Pu in a sample.

Journal Articles

$$gamma$$-ray pipe monitoring for comprehensive safeguards process monitoring of reprocessing facilities

Rodriguez, D.; Tanigawa, Masafumi; Mukai, Yasunobu; Isomae, Hidemi; Nakamura, Hironobu; Rossi, F.; Koizumi, Mitsuo; Seya, Michio

Proceedings of INMM 58th Annual Meeting (Internet), 9 Pages, 2017/07

Safegaurding nuclear material at reprocessing facilities utilizes sampling to verify the quantity and process monitoring to maintain continuity-of-knowledge to reduce re-verification. Solution Monitoring and Measurement Systems that determine the solution density and volume are installed at solution tanks, though this only provides indirect verification. To offset this safeguards limitation we propose measuring $$gamma$$ rays from solutions passing through the pipes and at the tanks to provide improved continuous monitoring and direct verification. This can provide both real-time flow measurements and Pu isotopic composition quantification through passive nondestructive assay. This concept was tested by recent experimental studies performed at the Japan Atomic Energy Agency's Plutonium Conversion Development Facility of flowing Pu-nitrate $$gamma$$ rays. This presentation will describe the concept details and analysis of using $$gamma$$ ray pipe monitoring as a capability for real-time safeguards verification.

Journal Articles

Shape evolution in neutron-rich krypton isotopes beyond N=60; First spectroscopy of $$^{98,100}$$Kr

Flavigny, F.*; Doornenbal, P.*; Obertelli, A.*; Delaroche, J.-P.*; Girod, M.*; Libert, J.*; Rodriguez, T. R.*; Authelet, G.*; Baba, H.*; Calvet, D.*; et al.

Physical Review Letters, 118(24), p.242501_1 - 242501_6, 2017/06

 Times Cited Count:14 Percentile:9.07(Physics, Multidisciplinary)

Journal Articles

Low-lying structure and shape evolution in neutron-rich Se isotopes

Chen, S.*; Doornenbal, P.*; Obertelli, A.*; Rodriguez, T. R.*; Authelet, G.*; Baba, H.*; Calvet, D.*; Ch$^a$teau, F.*; Corsi, A.*; Delbart, A.*; et al.

Physical Review C, 95(4), p.041302_1 - 041302_6, 2017/04

 Times Cited Count:11 Percentile:8.11(Physics, Nuclear)

Journal Articles

Delayed gamma-ray analysis for characterization of fissile nuclear materials

Koizumi, Mitsuo; Rossi, F.; Rodriguez, D.; Takamine, Jun; Seya, Michio; Bogucarska, T.*; Crochemore, J.-M.*; Varasano, G.*; Abbas, K.*; Pedersen, B.*; et al.

EUR-28795-EN (Internet), p.868 - 872, 2017/00

Journal Articles

Development of active neutron NDA techniques for nuclear nonproliferation and nuclear security, 7; Measurement of DG from MOX and Pu liquid samples for quantification and monitoring

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 ($$^{239}$$Pu, $$^{241}$$Pu, $$^{235}$$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.

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

Preliminary delayed $$gamma$$-ray spectroscopy for non-destructive analysis of fissionable material

Rodriguez, D.; Heyse, J.*; Koizumi, Mitsuo; Mondelaers, W.*; Pedersen, B.*; Schillebeeckx, P.*; Seya, Michio; Takamine, Jun

Proceedings of INMM 56th Annual Meeting (Internet), 8 Pages, 2015/07

There is a growing interest regarding how to effectively safeguard NM, specifically how to efficiently determine the composition of mixed materials. Currently researchers of the JAEA and JRC are discussing the development of a NDA system using a pulsed DT neutron source. The system will utilize a combination of DDA, NRTA, PGA, and DGS techniques. Of specific interest is applying this system toward determining the Pu/U composition of purified MOX fuel and non-purified NM. The DGS technique has the potential to establish fissionable material ratios to relatively high precision. These fission products generate time-dependent $$gamma$$-ray energy spectra that extend well above 3 MeV, a benefit when applied to the NM of interest that have high passive emissions. This presentation will describe initial studies regarding the precision that the DGS portion of this system can obtain and how it will be used in conjunction with the other techniques to analyze the composition of the NM of interest.

Journal Articles

Fatigue crack propagation experimental evaluation and modeling in an austenitic steel elbow from a LMFBR primary system piping

Garcia Rodriguez, D.; Sakakibara, Yasuhide*

Proceedings of 2014 ASME Pressure Vessels and Piping Conference (PVP 2014) (DVD-ROM), 9 Pages, 2014/07

The behavior of high temperature (400$$^{circ}$$C) low-cycle fatigue crack propagation during in-plane bending of an elbow from Monju LMFBR is presented in three stages. 1st, experimental measurements made in a real-size laboratory specimen are presented. This test was carried out under displacement-controlled conditions, with artificial defects introduced in the crown parts, where the maximum stress arises. 2nd, the experimental setup is simulated making use of FEA, in order to obtain the actual stress distribution through the loaded elbow. Finally, based on the FEA data, deterministic fatigue crack propagation based on the J-integral criterion is compared with the experimental data.

Journal Articles

3D FEA elastoplastic structural analysis of hypothetically cracked Monju FBR core support structures

Garcia Rodriguez, D.; Matsubara, Shinichiro

Proceedings of 22nd International Conference on Nuclear Engineering (ICONE-22) (DVD-ROM), 9 Pages, 2014/07

Structural reliability of the circumferentially cracked core support mount of Monju FBR is analyzed using FEA. The 3D shell model employed was derived after detailed evaluation of the core support mount behavior with a specific 3D solid model. 1st, elastoplastic static analysis shows that, under nominal operating conditions, the overall structure would be able to survive a total loss of the core support mount. 2nd, using the double elastic slope method it was inferred that earthquake loading integrity could be warranted up to a crack representing over 50% of the total circumference.

Journal Articles

In Japan and within the nuclear industry, four years and counting

Garcia Rodriguez, D.

Hozengaku, 12(4), p.45 - 47, 2014/01

In this short letter to appear in the Japanese Society of Maintenology's next issue, I present my living and working experience in Japan during the past 4 years. I came to live here for the first time in 2005, and stayed for one year as a fellow of the EU-JP Center for Industrial Cooperation Vulcanus Program, while carrying an 8 months internship at Hitachi GE Nuclear Energy. Then, after a 4 year break to obtain my PhD at the French Atomic Commission, I enrolled in JAEA as a permanent researcher in 2010.

Journal Articles

EMAT simulations based on a two-dimensional FEM coupled electro-mechanical formulation

Garcia Rodriguez, D.; Mihalache, O.; Ueda, Masashi

Proceedings of 16th International Symposium on Applied Electromagnetics and Mechanics (ISEM 2013), p.219 - 220, 2013/07

Oral presentation

Development of trouble data base of sodium-cooled fast reactor

Shimomura, Kenta; Garcia Rodriguez, D.*

no journal, , 

There is a longstanding interest to improve the in-service inspection (ISI) of nuclear power plants in general, and sodium fast reactors (SFR) in particular. With the goal of improving both safety and economic performance, a risk-informed approach to in-service inspection (RI-ISI) has therefore been earmarked for future commercial-scale SFR. A reliable RI-ISI, however, can only be established based on a rich operational experience record. For long, JAEA has compiled information about SFR troubles, but up to now such effort had been limited to specific types of troubles or components, while lacking the reliability and completeness required for the RI-ISI approach. In this paper we introduce recent work aiming to develop a comprehensive SFR trouble database based on original information sources, which both expands and improves any previously available documentation.

Oral presentation

A Two-dimensional EMAT code for non-magnetic materials using a coupled/uncoupled formulation

Mihalache, O.; Garcia Rodriguez, D.*; Yamamoto, Toshihiro*; Cheng, W.*

no journal, , 

Oral presentation

Development of active neutron NDA techniques for nuclear non-proliferation, 5; A Concept for a delayed $$gamma$$-ray spectroscopy measurement system

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

no journal, , 

As the part of basic development of the active neutron nondestructive measurement techniques with collaboration between JAEA and EC-JRC, A technical development of delayed $$gamma$$ spectrometry intended for determining ratio of fissile isotopes (e.g $$^{235}$$U, $$^{239}$$Pu, $$^{241}$$Pu) is being performed. For the purpose of design of neutron moderator for D-T neutron source used in DGS, simulations are performed using simplified model. We report the results and a concept of system based on them.

Oral presentation

Using an inverse Monte Carlo method to determine measurement uncertainties

Rodriguez, D.

no journal, , 

With the improvement of technology, safeguards verifications must consider how to declare precise uncertainties, especially for new non-destructive assay techniques. For our delayed $$gamma$$-ray spectroscopy technique, we are utilizing the inverse Monte Carlo analysis method. Systematic uncertainties are determined by analyzing full Monte Carlo spectra using the same analysis applied to the data. Preliminary results will be presented at this workshop.

Oral presentation

Space-time-energy distribution of neutron in a delayed $$gamma$$ ray measurement system with a 14-MeV D-T neutron source

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

no journal, , 

Among the nuclear materials, spent fuels and new fuels containing transuranic elements have a high neutron and $$gamma$$ ray background, so no certification measurement technique by nondestructive measurement has been established. In order to measure the composition ratio of fissile nuclides contained in nuclear material nondestructively, we are developing a delayed $$gamma$$ ray analysis method using a small pulsed D - T neutron generator. In the delayed $$gamma$$ ray analysis technique, it is important to decelerate the 14 MeV neutrons generated from the DT neutron source and generate a neutron field suitable for measurement. Therefore, a conceptual design of a device combining a neutron moderator with the Monte Carlo code MCNP 6 was performed. In order to confirm the effectiveness of the present moderator, neutron flux space inside the decelerator, energy distribution, and neutron flux time distribution were analyzed. From these results, it was found that the present moderator is optimal for delayed $$gamma$$ ray analysis technique, which can be confirmed experimentally.

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