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Journal Articles

Study on nondestructive measurement of nuclear materials in fuel debris by using fast neutron direct interrogation method

Maeda, Makoto; Furutaka, Kazuyoshi; Kureta, Masatoshi; Ozu, Akira; Tobita, Hiroshi; Komeda, Masao; Hattori, Kentaro

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-36-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2015/12

Fukushima Daiichi Nuclear Disaster in March 11th in 2011 is considered to produce fuel debris. It is difficult to measure nondestructively the amount of fissile materials in the fuel debris since the constituents of the debris are unknown and it may contain various materials such as water, metal, and even neutron absorber. A fast neutron direct interrogation (FNDI) method, which has been developed for long years to measure uranium bearing wastes drums, can measure an amount of nuclear materials regardless of a matrix of the wastes drums. We have studied nondestructive assay for nuclear materials in fuel debris by using the FNDI method. In this paper, we report on a design study of a nondestructive measurement system for debris canister and results of the investigation on the applicability of the FNDI method to the fuel debris containing various materials using Monte Carlo simulations.

Journal Articles

Characteristics of neutron resonance densitometry, 2; Neutron resonance capture analysis

Tsuchiya, Harufumi; Harada, Hideo; Koizumi, Mitsuo; Kitatani, Fumito; Kureta, Masatoshi; Becker, B.*; Kopecky, S.*; Heyse, J.*; Paradela, C.*; Mondelaers, W.*; et al.

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-36-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2015/12

Neutron Resonance Densitometry (NRD) was developed as a non-destructive assay to quantify U and Pu isotopes in particle-like debris. NRD is composed of neutron resonance transmission analysis (NRTA) and Neutron Resonance Capture Analysis (NRCA) or Prompt Gamma-ray Analysis (PGA). NRCA/PGA in NRD plays a role of identifying impurities in debris under the high-radiation field primarily caused by $$^{137}$$Cs. For this purpose, a novel LaBr$$_3$$ $$gamma$$-ray detector employing specific shields has been newly developed. With the developed $$gamma$$-ray detector, a demonstration NRCA experiment was performed at a neutron time of flight facility GELINA (Belgium). As a result, samples (Hf, Gd, Ni) placed in a black box that is completely sealed by third party were successfully identified by the experiment. This presentation explains the design concept of the $$gamma$$ ray detector including its detection principle and details of the demonstration NRCA experiment.

Journal Articles

Characteristics of neutron resonance densitometry, 1; Neutron resonance transmission analysis

Kitatani, Fumito; Harada, Hideo; Koizumi, Mitsuo; Tsuchiya, Harufumi; Kureta, Masatoshi; Becker, B.*; Kopecky, S.*; Heyse, J.*; Paradela, C.*; Mondelaers, W.*; et al.

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-36-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2015/12

From 2012 to 2014, Neutron Resonance Densitometry (NRD) is being developed as a non-destructive assay to quantify U and Pu isotopes. NRD is composed of neutron resonance transmission analysis (NRTA) and Neutron Resonance Capture Analysis (NRCA)/Prompt Gamma-ray Analysis (PGA). NRTA in NRD plays a role of quantifying the amounts of the isotopes of a nuclear fuel material (U, Pu) in molten fuel debris. Therefore, the neutron absorption measurement using Time-of-Flight (TOF) method is carried out. A demonstration NRTA experiment was performed at a neutron time of flight facility GELINA (Belgium). Consequently, we succeeded in iquantifying the randomly selected sample from Au, W, Rh, Nb, Cu. Co, Mn, B contained in a black box. In this presentation, we describe the principle of measurement of the developed NRTA and explain details of the demonstration experiment.

Journal Articles

Active neutron NDA techniques for nuclear non-proliferation applications, 1; Development plan

Kureta, Masatoshi; Koizumi, Mitsuo; Ozu, Akira; Tsuchiya, Harufumi; Furutaka, Kazuyoshi; Seya, Michio

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-36-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2015/12

The new program "Development of active neutron NDA techniques" has started for non-proliferation applications collaborating with EC-JRC. The final purpose of this program is to establish the measurement techniques for the high radioactive special nuclear material such as MA-Pu fuel for transmutation of minor actinide. In this program, the JAEA will conduct the R&D on active neutron non-destructive measurement techniques, DDA, NRTA, PGA/NRCA and DGS. The development plan and current status of the design study of the active neutron integrated test apparatus named "Active-N" are presented in this report.

Journal Articles

Development of sample assay system equipped with $$^{3}$$He Alternative Neutron Detectors (ASAS), 1; Design and fabrication of ASAS detector

Ozu, Akira; Tobita, Hiroshi; Kureta, Masatoshi; Tanigawa, Masafumi; Mukai, Yasunobu; Nakamichi, Hideo; Nakamura, Hironobu; Kurita, Tsutomu; Seya, Michio

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-36-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2015/12

Against the background of the serious shortage of $$^{3}$$He gas, the Japan Atomic Energy Agency (JAEA) has newly developed an alternative ZnS ceramic scintillation neutron detector for the safeguards, with the support of the government (MEXT). A demonstrator of plutonium inventory sample assay system (ASAS) has been also developed as an alternative HLNCC (High Level Neutron Coincidence Counter). The results from numerical simulations using Monte-Carlo code MCNPX showed that the fundamental performances of ASAS equipped with the 24 alternative neutron detectors, such as neutron detection efficiency and die-away time, equal to or higher than those of conventional HLNCC could be obtained. Here we present the inner mechanical structure of ASAS, together with the results of the simulating design.

Journal Articles

Nuclear security culture in comparison with nuclear safety culture; Resemblances and differences

Kawata, Norio

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-36-Kai Nenji Taikai Rombunshu (Internet), 7 Pages, 2015/12

Since the terrorist attacks on the U.S. on September 11th,2001, Nuclear Security has been focused on and treated as a global issue in the international community and it has also been discussed as a real and serious threat to nuclear power plants in the world since The Great East Japan Earthquake in March, 2011. The International Atomic Energy Agency (IAEA) issued a document including Nuclear Security Recommendations (INFCIRC/225/Rev.5) (NSS 13) in the Nuclear Security Series and emphasized the necessity of fostering Nuclear Security Culture. Nuclear Security Culture has been frequently discussed at various kinds of seminars and events. Since the officials in charge of Nuclear Security are familiar with the area of Nuclear Safety, the relationships between Nuclear Safety Culture and Nuclear Security Culture have been the point in controversy. This paper clarifies relevance between Nuclear Safety and Nuclear Security, considers resemblances and differences of their concepts and lessons learned for each culture from nuclear power plant accidents, and promotes deeper understanding of Nuclear Safety and Nuclear Security Culture.

Journal Articles

A Study on the Promotion of Nuclear Security Culture

Tamai, Hiroshi; Tazaki, Makiko; Kokaji, Lisa; Shimizu, Ryo; Suda, Kazunori

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-36-Kai Nenji Taikai Rombunshu (Internet), 7 Pages, 2015/12

In recent years the promotion of nuclear security culture aiming at strengthening nuclear security is extensively mentioned, however, awareness of nuclear security culture seems to be not much high compared to the permeation of nuclear safety culture. As a world's leading country of peaceful nuclear use, permeation of nuclear security culture into each personnel attitude must be one of important issues in Japan. Learning from the TEPCO Fukushima Daiichi Nuclear Power Plant accident, complementarity between nuclear safety and nuclear security in the aspect of both protection measures has been profoundly recognised. Therefore, it will be natural to promote nuclear security culture modelled on the preceding nuclear safety culture. On this standpoint, the paper examines an approach for the promotion of nuclear security culture which, for example, consists of awareness cultivation, attitude progress, permeation assessment, and resulting in the establishment of PDCA Cycle.

Journal Articles

Analysis of US policy on nuclear cooperation agreements

Tazaki, Makiko; Suda, Kazunori; Tamai, Hiroshi

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-36-Kai Nenji Taikai Rombunshu (Internet), 8 Pages, 2015/12

Since the enactment of the US Nuclear Nonproliferation Act of 1978, the US government has concluded nuclear cooperation agreements with other states (123 agreement) containing 9 nuclear non-proliferation conditions, in accordance with the 123 a. of the US Atomic Energy Act. Especially in the 21st century, 123 agreements can be analyzed as more detailed and diversified, due to the US government's case-by-case approach to 123 agreements, considering changes in international circumstances on nuclear proliferation concerns and expansion of peaceful use of nuclear energy. In this study, current US policy towards 123 agreements is analyzed through comparisons of various 123 agreements, particularly focusing on US approach to 9 nuclear nonproliferation conditions in the 123 agreements in the 21st century and also considering the other states' current environment on nuclear nonproliferation and nuclear energy utilization.

Journal Articles

Active neutron NDA techniques for nuclear non-proliferation applications, 4; Development of delayed gamma-ray spectroscopy; Experimental research plan

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

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-36-Kai Nenji Taikai Rombunshu (Internet), 6 Pages, 2015/12

The fission-product yield distributions are unique for each fissionable nuclide and interrogating neutron energy. Ratios of fissile materials (e.g. $$^{235}$$U, $$^{239}$$Pu, and $$^{241}$$Pu), therefore, could be deduced from differences in the observed neutron-induced Delayed Gamma-ray (DG) spectra characterized by the difference of these yields. This DG Spectroscopy (DGS) project includes research and development of a measurement system along with confirming and improving nuclear data. Experiments will be held at multiple facilities, including ITU/Ispra (Italy), IRMM/Geel (Belgium), and KURRI/Kumatori (Japan), using a wide range of neutron sources and nuclear material sample targets. The experimental efforts of this DGS project are described in this presentation.

Journal Articles

The Application of IAEA safeguards to joint comprehensive plan of action

Shimizu, Ryo; Tazaki, Makiko; Kokaji, Lisa; Tamai, Hiroshi; Suda, Kazunori

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-36-Kai Nenji Taikai Rombunshu (Internet), 6 Pages, 2015/12

On 14 July 2015, E3/EU+3 and Iran reached final agreement on the Joint Comprehensive Plan of Action (JCPOA) regarding Iran's nuclear program. Iran is now allowed to purse peaceful use of nuclear energy including uranium enrichment under certain pre-agreed conditions. From now on, IAEA inspection subjected to the agreed JCPOA will be further applied. Although Iran has not yet ratified the IAEA Additional Protocol (AP) to its Comprehensive Safeguards Agreement, it now provisionally applies the AP and consequently the IAEA is able to access every nuclear related facilities in Iran including not only uranium mines, but also any places and facilities which have been suspected to relate to nuclear weapon activities. In addition, the JCPOA introduces a new system of monitoring procurement of nuclear related materials and services by Iran. In the study, together with Iran's previous nuclear activities and outline of the JCPOA, various IAEA Safeguards activities in nuclear facilities in Iran and its challenges are analysed.

Journal Articles

Research on plutonium disposition by U.S. and Russia from the nonproliferation and nuclear security perspectives

Kokaji, Lisa; Suda, Kazunori; Tamai, Hiroshi; Tazaki, Makiko; Shimizu, Ryo

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-36-Kai Nenji Taikai Rombunshu (Internet), 7 Pages, 2015/12

After the Cold War, the United States and Russia have been decreasing the number of nuclear warheads under the Strategic Arms Reduction Treaty and other agreements, with step-by step removal from nuclear military programs under the process of nuclear disarmament. In 2000, the two states signed the Plutonium Management and Disposition Agreement (PMDA), which prescribes each of them to dispose of at least 34 metric tons of plutonium. Recently, since the cost of constructing the Mixed Oxide (MOX) Fabrication Facility has increased significantly, the United States has been assessing alternatives. In the revised PMDA, which defines weapon-grade plutonium as "an isotopic ratio of plutonium 240 to plutonium 239 of no more than 0.10", Article VII states, "Each Party shall have the right to conduct and the obligation to receive and facilitate monitoring and inspection activities", and Article VIII prescribes, "Each Party shall be responsible...for...disposition plutonium...taking into account...INFCIRC/225/Rev.4...". In accordance with the revised PMDA's obligation to dispose of an excess of 34 metric tons of plutonium, irradiation in fast reactors, irradiation of MOX fuel in LWRs, immobilization, downblending, and deep borehole options have been considered by the United States. In this research, it is examined how these options could be implemented from the nuclear nonproliferation and nuclear security perspectives.

Journal Articles

Development of sample assay system equipped with $$^{3}$$He Alternative Neutron Detectors (ASAS), 2; Results of ASAS measurement test

Tanigawa, Masafumi; Mukai, Yasunobu; Kurita, Tsutomu; Makino, Risa; Nakamura, Hironobu; Tobita, Hiroshi; Ozu, Akira; Kureta, Masatoshi; Seya, Michio

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-36-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2015/12

Against the background of the serious shortage of $$^{3}$$He gas, design and development of a new detector equipped ZnS/$$^{10}$$B$$_{2}$$O$$_{3}$$ ceramic scintillation neutron detectors in JAEA, with the support of the government (the Ministry of Education, Culture, Sports, Science & Technology). The design of the alternative $$^{3}$$He detector is referred from INVS (INVentory Sample assay system (HLNCC (High Level Neutron Coincidence Counter) type)) which is being used for the verification of MOX powder etc. and is named it as ASAS (Alternative Sample Assay System). In order to prove the Pu quantitative performance as an alternative technology, several measurement tests and comparison test with INVS were conducted using ASAS. In these tests, evaluation of fundamental performance (counting efficiency and die-away time) and uncertainty evaluations were implemented. As a result, although fundamental performance of ASAS was not achieved to the one of INVS, we could confirm that ASAS has almost the same Pu quantitative performance including measurement uncertainty as that of INVS.

Journal Articles

Conceptual proposal of new detection method for unauthorized removal of nuclear materials from glovebox

Mukai, Yasunobu; Nakamura, Hironobu; Tanigawa, Masafumi; Nakamichi, Hideo; Umino, Yoshinori; Fujisaku, Sakae; Kimura, Takashi; Kurita, Tsutomu

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-36-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2015/12

When the unauthorized removal of nuclear materials (NM) from glovebox (GB) by an insider happens, it needs to be detected and reported immediately. In this time, for utilization of the security counterplan, the feasibility of a new detection concept for the unauthorized removal was investigated with implementation of several experiments considering actual GB operation. In general, the detection method using radiation monitor is thought of easily. However, it is very difficult to distinguish between authorized NM movement during operation and the unauthorized removal. To solve this subject, JAEA focused on negative pressure monitoring of GB, and investigated a new detection concept combining the neutron and negative pressure monitoring. As a result of the experiments in small-scale GB, it was revealed that this new concept had the capability to detect the unauthorized removal and to alarm to central alarm station rapidly, and had the possibility to enhance the effectiveness of the current physical protection measures.

Oral presentation

Investigation on radioxenon background in Mutsu related to CTBT verification

Kijima, Yuichi; Yamamoto, Yoichi; Oda, Tetsuzo

no journal, , 

The International Noble Gas Experiment (INGE) is being carried out for global measurement networks of radioactive noble gas (xenon), as part of building of the international verification regime of the Comprehensive nuclear-Test-Ban Treaty (CTBT). Since there are many nuclear facilities and medical institutions in Japan and its neighboring countries, which may be possible sources of radioxenon, it is important to understand the behavior of normal radioxenon background for high-precision detection of underground nuclear tests. Therefore, for the purpose of the investigation on radioxenon background in Northeast Asia region, the measurement of radioxenon was conducted in Mutsu city, Aomori in 2012, and the results showed that radioxenon background in Mutsu was regionally specific and different from that in Takasaki. In 2014, the additional measurement was carried out at the same place for further investigation. This report describes the results of background measurement in Mutsu city in 2014.

Oral presentation

Feasibility study of Pu monitoring technology for Pu solution with FP; Overview and research plan

Sekine, Megumi; Ishiyama, Koichi; Nakamura, Hironobu; Tomikawa, Hirofumi

no journal, , 

Plutonium (Pu) solution and solid waste containing fission products (FP) are stored in a reprocessing plant as inventory or retained waste. It is difficult to access the Pu with FP since it has an extremely high radiation dose rate, and there is no direct Pu continuous monitoring/verification technology. From a viewpoint of ensuring nuclear transparency, Japan Atomic Energy Agency (JAEA) has started to develop a new technology using non-destructive assay to measure and monitor Pu solution with FP since JFY 2015. The technology could be applicable to Pu concentration monitoring throughout the reprocessing process. In the poster presentation, an overview of the technology development, simulation results of preliminary evaluation of the characteristics of radiation emitted from the high level radioactive liquid waste tank at Tokai Reprocessing Plant, where the test field is located, and the future research plan are presented.

Oral presentation

Validation tests and measuring trials for actual uranium bearing waste drums by the fast neutron direct interrogation method

Zaima, Naoki; Nakatsuka, Yoshiaki; Nakashima, Shinichi; Ozu, Akira; Komeda, Masao; Kureta, Masatoshi

no journal, , 

JAEA developed NDA systems which applied to the actual scrapped nuclear materials and uranium bearing waste drums heavily generated from URCP and NEP in Ningyo-site. In order to improve the methodology of determination uranium mass the active assay neutron NDA measurement system (JAEA Waste Assay System-Ningyo=JAWAS-N) used by the Fast Neutron Direct Interrogation (FNDI) method have been configurated. The validation tests have been achieved successfully, also the trials for measuring the actual nuclear materials or waste drums just started and accumulated over 550 data with quick and high accuracy measuring. The die-away time, which means neutron decay time in phenomenon, may be used for analyzing uranium mass, at the same time, the neutron behavior simulations over time spectrum have been carried out and verified our measurement system.

Oral presentation

Current status of accompanying FP passive $$gamma$$ measurement to special nuclear material quantification in fuel debris

Shiba, Tomooki; Sagara, Hiroshi*; Hiyama, Toru; Tomikawa, Hirofumi

no journal, , 

In response to the accident at Fukushima Daiichi Nuclear Power Station, passive $$gamma$$ spectrometry has been researched and developed as one of the candidates of a mass measurement method of the special nuclear materials in molten core material. Among Fission Products (FPs) accompanied in molten core materials, some of them are very low-volatile and emit high-energy $$gamma$$ rays which enable to derive the mass of those FPs by passive $$gamma$$ spectrometry. Using the mass ratio between the FPs and nuclear materials, this technique provides the mass estimation of nuclear materials. This technique is relatively simple and was applied to the analysis of nuclear materials in the clean-up process of damaged Three Mile Island unit-2 (TMI-2) reactor. In the poster, we show the outlines of the project, the analytical and experimental results conducted until now, and the future plan of the project.

Oral presentation

Generation of laser Compton $$gamma$$-rays using Compact ERL

Shizuma, Toshiyuki; Hajima, Ryoichi; Nagai, Ryoji; Hayakawa, Takehito; Mori, Michiaki; Seya, Michio

no journal, , 

Nondestructive isotope-specific assay system using nuclear resonance fluorescence has been developed at JAEA. In this system, intense, mono-energetic laser Compton scattering (LCS) $$gamma$$-rays are generated by combining an energy recovery linac (ERL) and laser enhancement cavity. As technical development for such an intense $$gamma$$-ray source, we demonstrated generation of LCS $$gamma$$-rays using Compact ERL (supported by the Ministry of Education, Culture, Sports, Science and Technology) developed in collaboration with KEK. We also measured X-ray fluorescence for elements near iron region by using mono-energetic LCS $$gamma$$-rays. In this presentation, we will show results of the experiment and future plan.

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