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Journal Articles

Characterization study of four candidate technologies for nuclear material quantification in fuel debris at Fukushima Daiichi Nuclear Power Station

Nagatani, Taketeru; Komeda, Masao; Shiba, Tomooki; Nauchi, Yasushi*; Maeda, Makoto; Sagara, Hiroshi*; Kosuge, Yoshihiro*; Kureta, Masatoshi; Tomikawa, Hirofumi; Okumura, Keisuke; et al.

Energy Procedia, 131, p.258 - 263, 2017/12

 Times Cited Count:2 Percentile:11.38

Journal Articles

Applicability evaluation of candidate technologies for nuclear material quantification in fuel debris at Fukushima Daiichi Nuclear Power Station; Passive neutron technique (Interim report)

Nagatani, Taketeru; Kosuge, Yoshihiro*; Shirato, Atsuhiko*; Sato, Takashi*; Shiromo, Hideo; Asano, Takashi

Proceedings of INMM 57th Annual Meeting (Internet), 10 Pages, 2016/07

Journal Articles

Study on improving measurement accuracy of Epithermal Neutron Measurement Multiplicity Counter (ENMC)

Nomi, Takayoshi; Kawakubo, Yoko; Nagatani, Taketeru; Shiromo, Hideo; Asano, Takashi; Menlove, H. O.*; Swinhoe, M. T.*; Browne, M. C.*

Proceedings of INMM 57th Annual Meeting (Internet), 9 Pages, 2016/07

Journal Articles

Characterization study of four candidate technologies for nuclear material quantification in fuel debris at Fukushima Daiichi Nuclear Power Station (Interim report)

Nagatani, Taketeru; Komeda, Masao; Shiba, Tomooki; Maeda, Makoto; Nauchi, Yasushi*; Sagara, Hiroshi*; Kosuge, Yoshihiro*; Kureta, Masatoshi; Tomikawa, Hirofumi; Okumura, Keisuke; et al.

Proceedings of INMM 57th Annual Meeting (Internet), 10 Pages, 2016/07

Journal Articles

Experimental studies of passive neutron measurement for fuel debris at Fukushima Daiichi Nuclear Power Plants

Nagatani, Taketeru; Shirato, Atsuhiko*; Kosuge, Yoshihiro*; Sato, Takashi*; Kawakubo, Yoko; Shiromo, Hideo; Asano, Takashi

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

As one of the candidate material accountancy technologies for the fuel debris at Fukushima Daiichi Nuclear Power Plants (1F), we propose the application of a passive neutron technique. The applicability of the new concept to the fuel debris at 1F was evaluated by simulation and the results were presented at the last INMM annual meeting. As the next phase, we conducted experimental tests to confirm the validity of the simulation results. Because actual fuel debris or irradiated fuel cannot be handled at our facility due to a licensing limitation, un-irradiated MOX samples, neutron absorbers and Cf-252 sources were utilized as the best available material to imitate the property of the fuel debris and various configurations were measured using an Epithermal Neutron Multiplicity Counter. The fissile mass in the samples, neutron absorber mass surrounding the samples and intensity of Cf-252 source were varied to confirm the correlation between DDSI response and the leakage multiplication. Test results agreed well with the trend of the simulation results. This indicates that DDSI has sufficient capability to evaluate the leakage multiplication of a sample which includes an unknown amount of fissile material and neutron absorber such as the fuel debris at 1F. This paper provides experimental studies of passive neutron measurement based on the combination of DDSI technique and coincidence counting for fuel debris at 1F.

Journal Articles

JAEA's contribution to development of J-MOX safeguards system

Nagatani, Taketeru; Nakajima, Shinji; Kawakubo, Yoko; Shiromo, Hideo; Asano, Takashi; Marlow, J.*; Swinhoe, M. T.*; Menlove, H.*; Rael, C.*; Kawasue, Akane*; et al.

Book of Abstracts, Presentations and Papers of Symposium on International Safeguards; Linking Strategy, Implementation and People (Internet), 8 Pages, 2015/03

Journal Articles

Monte Carlo N-Particle eXtended (MCNPX) simulation for passive neutron measurement of fuel debris at Fukushima Daiichi Nuclear Power Plants

Nagatani, Taketeru; Nakajima, Shinji; Kosuge, Yoshihiro*; Shiromo, Hideo; Asano, Takashi

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

Meltdown of the reactor cores of Units 1-3 occurred at Fukushima Daiichi Nuclear Power Plants (1F). Fuel debris at 1F contains minor actinides and fission products and neutron absorber. These materials make it difficult to quantify fertile nuclear materials in fuel debris by the conventional passive neutron technique. We consider that DDSI and PNAR which focused on fissile material are promising techniques to quantify the nuclear materials in the fuel debris. A concept of application of these techniques to fuel debris measurement was investigated and presented at the last INMM annual meeting. In order to evaluate the applicability of these techniques to fuel debris measurement, we investigated the neutron behavior in the fuel debris by using MCNPX simulation code. Because property of fuel debris is not clear, source term data used were prepared by referring TMI data. This paper provides results of MCNPX simulation for fuel debris measurement at 1F with passive neutron techniques.

Journal Articles

Performance test results for the Advanced Fuel Assembly Assay System (AFAS) on the active length verification of LWR MOX fuel assembly by neutron detectors

Nakajima, Shinji; Nagatani, Taketeru; Shiromo, Hideo; Asano, Takashi; Marlow, J. B.*; Swinhoe, M. T.*; Menlove, H. O.*; Rael, C. D.*; Kawasue, Akane*; Iso, Shoko*; et al.

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

The Advanced Fuel Assembly Assay System (AFAS) is an unattended non-destructive assay (NDA) system by neutron measurement to verify the plutonium amount in an LWR plutonium and uranium mixed oxide (MOX) fuel assembly. The assembly will be fabricated in the MOX fuel fabrication plant under construction by the Japan Nuclear Fuel Limited. The AFAS has been developed by Los Alamos National Laboratory under the auspices of the Secretariat of Nuclear Regulation Authority in Japan. The AFAS is the first NDA system which will verify the active length of the assembly without inspector attendance. Japan Atomic Energy Agency (JAEA) has conducted the performance test for the AFAS under the contract with Nuclear Material Control Center to demonstrate this active length verification technology by using MOX fuel assemblies owned by JAEA. As the results, it was confirmed that measurement error of the active length for the MOX fuel assembly was less than 0.1% and it was satisfied with requirement by IAEA. This paper provides the performance test results for the active length verification of the AFAS.

Journal Articles

Performance test results of the Advanced Verification for Inventory Sample System (AVIS), 2

Nakajima, Shinji; Nagatani, Taketeru; Asano, Takashi; Kawasue, Akane*; Iso, Shoko*; Kumakura, Shinichi*; Watanabe, Takehito*; Marlow, J. B.*; Swinhoe, M. T.*; Menlove, H. O.*; et al.

Kaku Busshitsu Kanri Gakkai (INMM) Nippon Shibu Dai-34-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2013/10

The Advanced Verification for Inventory Sample System (AVIS) is a nondestructive assay (NDA) system in order to verify the plutonium mass in the small MOX samples at Japan Nuclear Fuel Limited (JNFL) MOX fuel fabrication plant (J-MOX) under construction. The AVIS is required the high measurement performance because the AVIS will be used as a verification tool to substitute destructive analysis for a part of the samples which needs the bias defect verification. Therefore, the AVIS will fulfill an important role in the safeguards approach for J-MOX. Japan Atomic Energy Agency (JAEA) conducted the performance test of the AVIS under the contract with NMCC. As the results of these tests, we confirmed that the AVIS could almost satisfy the required performance by IAEA.

Journal Articles

Feasibility study on passive neutron technique applied to fuel debris measurement at Fukushima Daiichi Nuclear Power Plants

Nagatani, Taketeru; Nakajima, Shinji; Asano, Takashi

Proceedings of INMM 54th Annual Meeting (CD-ROM), 8 Pages, 2013/07

Fukushima Daiichi Nuclear Power Plants (1F) were struck by the earthquake and tsunami on March 11, 2011 and meltdown of the reactor cores of Units 1-3 occurred. Japan decided decommissioning of them. For decommissioning of 1F, Japan plans to recover fuel debris safely and to account nuclear material in it adequately. Survey of applicable technologies for nuclear material quantification of fuel debris, currently, is being conducted by Japan Atomic Energy Agency (JAEA) and United States Department of Energy (DOE) under the collaborative agreement. This survey will identify technologies with the most promising capability to meet IAEA safeguards needs. As one of candidate technologies of plutonium quantification in fuel debris, we, Plutonium Fuel Development Center of JAEA, consider the application of the passive neutron technique which is wildly applied to the field of material accountancy and safeguards in plutonium handing facilities. Fuel debris contains minor actinides and fission products which are intense neutron and $$gamma$$ ray emitter due to burn-up of fuel in the reactor. It also contains neutron absorber such as gadolinium included in fuel to moderate burn-up and boron added after accident to avoid re-criticality. These materials make it difficult to quantify plutonium by the current passive neutron technique. Therefore, R&D activities regarding selective counting for neutron derived from plutonium, reduction of $$gamma$$ ray influence and estimation of neutron absorber influence are required in order to overcome above difficulties. This paper provides a concept for application of passive neutron technique to fuel debris measurement.

Journal Articles

Performance test results of the advanced verification for inventory sample system (AVIS)

Nakajima, Shinji; Nagatani, Taketeru; Asano, Takashi; Marlow, J. B.*; Swinhoe, M. T.*; Menlove, H. O.*; Rael, C. D.*; Kawasue, Akane*; Iso, Shoko*; Kumakura, Shinichi*; et al.

Proceedings of INMM 54th Annual Meeting (CD-ROM), 10 Pages, 2013/07

The advanced verification inventory system (AVIS) is a nondestructive assay (NDA) system developed by Los Alamos National Laboratory (LANL) to measure small samples of bulk plutonium and uranium mixed oxide (MOX) powder and pellets at the Japan Nuclear Fuel Limited (JNFL) mixed oxide fuel fabrication plant (J-MOX). In order to mitigate the workload on the Rokkasho On-Site Laboratory (OSL), it is intended that the AVIS measurement will be substituted for a part of the Destructive Assay (DA) for J-MOX. Based on the commission from Office for Nuclear Non-Proliferation and Safeguards (JSGO) of Ministry of Education, Culture, Sports, Science and Technology (MEXT) and Nuclear Material Control Center (NMCC), Japan Atomic Energy Agency (JAEA) has conducted the performance test of the AVIS in order to confirm the system performance before installation at the J-MOX site. The performance test consists of two phases. In the phase 1 test, detector parameters such as detector efficiency and die-away time were evaluated by using a californium-252 neutron source. These results agreed well with design value and were reported at the 53rd INMM annual meeting. JAEA conducted the phase 2 test by using MOX materials in order to evaluate the total measurement uncertainty (TMU). In the test, influence of sample density, plutonium concentration and organic additives in samples were also evaluated. Consequently, it is expected that AVIS can achieve the target TMU of 0.5% required in user requirement of IAEA by optimizing measurement condition and by using well-characterized standards. This paper provides a summary of the results of comprehensive performance test of AVIS.

Journal Articles

Interim report of performance test of the advanced verification for inventory sample system (AVIS)

Nagatani, Taketeru; Nakajima, Shinji; Asano, Takashi; Marlow, J. B.*; Swinhoe, M. T.*; Menlove, H. O.*; Rael, C. D.*; Kawasue, Akane*; Iso, Shoko*; Kumakura, Shinichi*; et al.

Proceedings of INMM 53rd Annual Meeting (CD-ROM), 9 Pages, 2012/07

The advanced verification for inventory sample system (AVIS) is a nondestructive assay (NDA) system designed to measure small samples of bulk plutonium uranium mixed oxide (MOX) powder and pellets at the proposed Japan Nuclear Fuel Limited (JNFL) mixed oxide fuel fabrication plant (J-MOX). The system consists of a $$^{3}$$He-based passive neutron well counter with an integrated high-purity germanium $$gamma$$ system. The AVIS is intended to meet a performance specification of a total measurement uncertainty of less than 0.5% in the neutron ($$^{240}$$Pu effective) measurement. It is intended that the AVIS measurement will be substituted for a fraction of the DA samples from J-MOX. JAEA has conducted performance testing on the AVIS in order to confirm the system performance before installation and to minimize the period of calibration at J-MOX site. In this paper, we provide a summary of the result of performance test phase 1 and the test plan of performance test phase 2 of the AVIS.

Journal Articles

Experience on implementation of the Integrated Safeguards approach for the MOX facility from the operator's point of view

Nomi, Takayoshi; Nagatani, Taketeru; Ninagawa, Junichi; Nakajima, Shinji; Maruyama, Hajime; Asano, Takashi; Fujiwara, Shigeo

Kaku Busshitsu Kanri Gakkai (INMM) Nippon Shibu Dai-32-Kai Nenji Taikai Rombunshu (Internet), 8 Pages, 2011/11

The IS approach for the JNC-1 site was implemented in August 2008, and this was the first experience in the world. This IS approach aimed not only to improve efficiency and effectiveness of safeguards but also to reduce burden of the plant operation by improvement of efficiency of the inspection activity. It was planned to review effectiveness of this new approach after three years from implementation. And JAEA also evaluated effects by application of the IS approach for two MOX fuel facilities in the JNC-1 site based on the three years experiences from the operator's view point. As the result of evaluation, it was confirmed that there were some difference of benefits by application of the IS approach depending on features of the facility, automation level of equipment and advance level of safeguards systems.

Journal Articles

Report on INMM 52nd Annual Meeting, 2; Mainly spent fuel measurement session

Nagatani, Taketeru

Kaku Busshitsu Kanri Senta Nyusu, 40(10), p.6 - 7, 2011/10

no abstracts in English

Journal Articles

Evaluation of application effect of the integrated safeguards approach for MOX fuel fabrication facilities from the operator's viewpoint

Ninagawa, Junichi; Asano, Takashi; Nagatani, Taketeru; Nakajima, Shinji; Nomi, Takayoshi; Fujiwara, Shigeo

Proceedings of INMM 52nd Annual Meeting (CD-ROM), 8 Pages, 2011/07

Japan was transferred to the Integrated Safeguards (IS) scheme in September 2004. The IS approach for JNC-1 site, including PFPF, was developed to improve the efficiency of safeguards while maintaining the effectiveness and has been implemented since August 2008. JAEA has evaluated the validity of the IS approach for PFPF based on the historical performance over about three-year period. As the result of evaluation, JAEA confirmed the improvement of efficiency of inspection activities and the reduction of the impact of inspection activities on plant operation. On the other hand, the IAEA has also evaluated the validity of IS approach and considered to modify based on the result of its evaluation. In order to maintain or improve the validity of the IS approach, JAEA thinks that it will be necessary to work very closely and honestly with the inspectorate to address this modification process.

Journal Articles

The Impact of advanced technologies on the efficiencies of safeguards and facility operations

Hoffheins, B.; Miyaji, Noriko; Asano, Takashi; Nagatani, Taketeru; Ishiyama, Koichi; Kimura, Takashi; Kodani, Yoshiki

Proceedings of INMM 52nd Annual Meeting (CD-ROM), 10 Pages, 2011/07

Following Japan's conclusion of the Additional Protocol and the IAEA's broader conclusion regarding the peaceful nature of Japan's nuclear activities, the Japan government and facility operators have worked with the IAEA to apply integrated safeguards to increase inspection efficiency and to ensure verification correctness and completeness. These safeguards approaches rely heavily on the implementation of advanced technologies such as unattended surveillance and non-destructive assay measurement, automated nuclear material accounting, solution monitoring and remote monitoring. These technologies have enabled random interim inspections; they have also reduced the level of effort required for nuclear material accounting and inspection activities. A more comprehensive understanding of the impact of advanced technologies on operation and inspection processes would be useful for developing methodologies to support better system design and evaluation of existing systems.

Journal Articles

High-accuracy measurement of plutonium mass by non-destructive assay; An Improved approach for the effectiveness and efficiency of safeguards

Nagatani, Taketeru; Nakajima, Shinji; Asano, Takashi; Fujiwara, Shigeo; Menlove, H. O.*; Swinhoe, M. T.*; Browne, M. C.*

Journal of Nuclear Materials Management, 39(3), p.4 - 10, 2011/04

Journal Articles

Operator's experience on random interim inspection for MOX fuel plant at JNC-1 site

Nagatani, Taketeru; Asano, Takashi; Fujiwara, Shigeo; Takahashi, Saburo

Proceedings of INMM 50th Annual Meeting (CD-ROM), 10 Pages, 2009/00

By implementation of the Integrated Safeguards Approach, the inspection scheme of JNC-1 site was transferred from the scheduled inspections to RII with short notice. The development of RII was considered under the precondition that it would be conducted without interruption of facility operation. JAEA proposed verification procedures to mitigate the influence on facility operation by the RII. The influence on facility operation by inspection activities of RII was drastically mitigated in comparison with the traditional IIV though implementation of the RII required additional efforts of the operator. This paper reports JAEA's efforts for implementation of RII with short notice in order to mitigate the influence of facility operation by inspection and the impact it has on the facility operation from the operator's standpoint.

Journal Articles

Development of integrated safeguards approach for JNC-1 site from the operator's viewpoint

Asano, Takashi; Fujiwara, Shigeo; Takahashi, Saburo; Nagatani, Taketeru; Fukuhara, Junichi; Kodani, Yoshiki; Kimura, Takashi; Miura, Yasushi

Proceedings of INMM 50th Annual Meeting (CD-ROM), 10 Pages, 2009/00

JAEA commenced to consider the integrated safeguards (IS) approach for JNC-1 site as the new concept of safeguards for further reduction of influence of facility operation by the safeguards activity. On the other hand, the board of governors of IAEA led the broader conclusion to Japan on June 2004 and safeguards implementation in Japan was transferred to the IS scheme in September 2004. IAEA aimed to improve efficiency of safeguards implementation for the plutonium handling facility by optimization of use of advanced safeguards systems and new safeguards regime without reduction of effectiveness of safeguards. The IS approach for JNC-1 site was developed and implemented on August 2008 after many discussions among IAEA, Japan Safeguards Office (JSGO) and JAEA. This paper shows contributions by JAEA to development of this approach from the operator's view point and influence to the operator by implementation of IS approach.

Journal Articles

Integrated safeguards for the plutonium fuel production facility (RFPF); Development of approach and applications

Nagatani, Taketeru; Asano, Takashi; Fujiwara, Shigeo; Takahashi, Saburo

Proceedings of JAEA-IAEA Workshop on Advanced Safeguards Technology for the Future Nuclear Fuel Cycle (Internet), 8 Pages, 2007/11

Safeguards implementation in Japan was transferred to an integrated safeguards (IS) scheme in September 2004. Around that time, IS approach was implemented for all of the light water reactors and LEU fuel fabrication facilities. Based on the SAGSI advice, the JAEA developed an IS approach for Plutonium Fuel Production Facility (PFPF) and proposed to the IAEA. Based on the JAEA proposal, the IAEA proposed the IS approach for not only PFPF but also for other facilities in the JNC-1 site in May 2005. The concept for this approach was agreed upon between the IAEA and the Japan side in November 2006. The IAEA has a target to start implementation of the IS approach for the JNC-1 site in January 2008. This report introduces the IS approach for MOX fuel fabrication facilities in the JNC-1 site and considers the perspective for the future.

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