Refine your search:     
Report No.
 - 
Search Results: Records 1-7 displayed on this page of 7
  • 1

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Prospective features for integration of nuclear forensics capability in national framework

Tamai, Hiroshi; Okubo, Ayako; Kimura, Yoshiki; Shinohara, Nobuo; Tazaki, Makiko; Shimizu, Ryo; Suda, Kazunori; Tomikawa, Hirofumi

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

Nuclear forensics is a technical measure to analyse and collate samples of illegally used nuclear materials, etc., to clarify their origins, routes, etc. and contribute to criminal identifications. Close collaboration with police and judicial organizations is essential. The national response framework is being built up with international cooperation. Discussions on promoting technical capability and regional cooperation are presented.

Journal Articles

Feasibility study of advanced measurement technology for solution monitoring at reprocessing plant; Dose rate measurement for the solution including Pu with FP

Matsuki, Takuya; Yamanaka, Atsushi; Sekine, Megumi; Suzuki, Satoshi*; Yasuda, Takeshi; Tsutagi, Koichi; Tomikawa, Hirofumi; Nakamura, Hironobu; LaFleur, A. M.*; Browne, M. C.*

Proceedings of INMM 58th Annual Meeting (Internet), 8 Pages, 2017/07

The Tokai Reprocessing Plant (TRP) has been developing a new detector from 2015 to 2017 for purpose to monitor Pu amount in High Active Liquid Waste (HALW) containing FP. It can make a contribution to an advanced approach to effectively and efficiently conduct safeguards for reprocessing facilities because it becomes available to monitor and verify nuclear material movement continuously by a new detector, which has proposed by IAEA. For the second step of this project, we conducted dose rate measurement on the guide rail installing in the cell storing the HALW tank and comparison between measured dose rate distribution and calculation result by MCNP simulation in order to investigate the dose rate distribution which is needed for shielding design of a new detector that is used for radiation (neutron/$$gamma$$ spectrum) measurement in the cell and inquest on the monitoring position of the detector for Pu monitoring. In this paper, we report the result of the dose rate measurement in the cell, improvement of the simulation model which is cleared by comparison between measurement result and calculation result and our future plan.

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

A Proposal of secure non-destructive detection system of nuclear materials in heavily shielded objects and interior investigation system

Seya, Michio; Hajima, Ryoichi*; Kureta, Masatoshi

Proceedings of INMM 58th Annual Meeting (Internet), 10 Pages, 2017/07

Large size freight cargo containers are the most vulnerable items from nuclear security points of view because of their large volume and weight of cargo inside for hiding heavily shielded objects. For strengthening nuclear security, secure detection of NMs in heavily shielded objects, and safe handling (dismantlement) of detected (suspicious) objects, are essential. These require secure detection of NMs, inspection of detailed interior structures of detected objects, rough characterization of NMs (for nuclear bomb or RDD etc.) and confirmation of existence of explosives etc. By using information obtained by these inspections, safe dismantlement of objects is possible. In this paper, we propose a combination of X-ray scanning system with NRF-based NDD system using monochromatic $$gamma$$-ray beam for a secure detection and interior inspections. We also we propose active neutron NDA system using a DT source for interior inspection of NM part.

Journal Articles

Effects of $$gamma$$-ray polarization in NRF-based nondestructive assay of nuclear materials

Omer, M.; Hajima, Ryoichi*; Shizuma, Toshiyuki*; Koizumi, Mitsuo

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

Nuclear resonance fluorescence (NRF) is a process in which the electric and/or the magnetic dipole excitations of the nucleus take place. Since these excitations are unique signatures of each nucleus, the NRF provides a practical tool for a non-destructive detection and assay of nuclear materials. Using a polarized $$gamma$$-ray beam, distinguishing the nature of the excitation is straightforward. At a scattering angle of 90$$^{circ}$$, the electric dipole excitations are radiated normal to the polarization plane whereas the magnetic dipole excitations are radiated in the same plane as the incident beam polarization. By contrast, other $$gamma$$-ray interactions with the atom may exhibit different responses regarding the polarization of the incident beam. For example, the elastic scattering is expected to give approximately 60% lower yield in the direction of the incident beam polarization than the other direction. This fact significantly affects the sensitivity of the NRF technique because it is not possible to separate the NRF and the elastic scattering on the basis of the photon energy. We report the results of a photon scattering experiment on $$^{238}$$U using a 100% linearly polarized $$gamma$$-ray beam with an energy of 2.04 MeV. We demonstrate how the elastic scattering responds to the polarization of the incident beam. Accordingly, we are able to resolve the effects of the polarization of incident photon in an NRF measurement.

7 (Records 1-7 displayed on this page)
  • 1