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JAEA Reports

Safe, efficient cementation of challenging radioactive wastes using alkali activated materials with high-flowability and high-anion retention capacity (Contract research); FY2020 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Hokkaido University*

JAEA-Review 2021-036, 95 Pages, 2021/12

JAEA-Review-2021-036.pdf:5.13MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2020. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2019, this report summarizes the research results of the "Safe, efficient cementation of challenging radioactive wastes using alkali activated materials with high-flowability and high-anion retention capacity" conducted in FY2020. For safe storage and disposal of iron sludge generated from contaminated water treatment, the present study aims to 1) explore alkali activated materials (AAM) with high-flowability and high-anion retention capacity and its recipe, 2) try mock-up manufacture and evaluation for one-tenth the size of real waste and propose the concept of the manufacturing equipment for a real plant, 3) show potential of AAM as the material for the solidification of waste with various physicochemical properties and radioactive nuclide compositions from the result of

JAEA Reports

Safe, efficient cementation of challenging radioactive wastes using alkali activated materials with high-flowability and high-anion retention capacity (Contract research); FY2019 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Hokkaido University*

JAEA-Review 2020-054, 72 Pages, 2021/01

JAEA-Review-2020-054.pdf:5.62MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2019. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2019, this report summarizes the research results of the "Safe, efficient cementation of challenging radioactive wastes using alkali activated materials with high-flowability and high-anion retention capacity". The purpose of this study is to find safe, efficient cementation of challenging radioactive wastes using alkali activated materials with high-flowability and high-anion retention capacity, and to propose the concept of a manufacturing apparatus that is established as an actual plant. As a result of study in this year, it was revealed that the K-based alkali activated material has high-flowability and quick curing, and that high-iodine retention capacity is achieved by incorporating silver ions during manufacturing of solidified waste.

JAEA Reports

Decommissioning of the Uranium Enrichment Laboratory

Kokusen, Junya; Akasaka, Shingo*; Shimizu, Osamu; Kanazawa, Hiroyuki; Honda, Junichi; Harada, Katsuya; Okamoto, Hisato

JAEA-Technology 2020-011, 70 Pages, 2020/10

JAEA-Technology-2020-011.pdf:3.37MB

The Uranium Enrichment Laboratory in the Japan Atomic Energy Agency (JAEA) was constructed in 1972 for the purpose of uranium enrichment research. The smoke emitting accident on 1989 and the fire accident on 1997 had been happened in this facility. The research on uranium enrichment was completed in JFY1998. The decommissioning work was started including the transfer of the nuclear fuel material to the other facility in JFY2012. The decommissioning work was completed in JFY2019 which are consisting of removing the hood, dismantlement of wall and ceiling with contamination caused by fire accident. The releasing the controlled area was performed after the confirmation of any contamination is not remained in the target area. The radioactive waste was generated while decommissioning, burnable and non-flammable are 1.7t and 69.5t respectively. The Laboratory will be used as a general facility for cold experiments.

JAEA Reports

Material balance analysis for wide range of nuclear power generation scenarios

Nishihara, Kenji

JAEA-Data/Code 2020-005, 48 Pages, 2020/07

JAEA-Data-Code-2020-005.pdf:2.95MB
JAEA-Data-Code-2020-005-appendix(CD-ROM).zip:3.62MB

In order to discuss the technological development and human resource development necessary for the future nuclear fuel cycle, various quantitative analyzes were conducted assuming a wide range of future nuclear power generation scenarios. In the evaluation of quantities, the future power generation of LWR and fast reactor, the amount of spent fuel reprocessing, etc. were assumed, and the amount of uranium demand, the accumulation of spent fuel, plutonium, vitrified waste etc. were estimated.

Journal Articles

Development of experimental technology for simulated fuel-assembly heating to address core-material-relocation behavior during severe accident

Abe, Yuta; Yamashita, Takuya; Sato, Ikken; Nakagiri, Toshio; Ishimi, Akihiro

Journal of Nuclear Engineering and Radiation Science, 6(2), p.021113_1 - 021113_9, 2020/04

JAEA Reports

Development of imaging system with ultra-high spatial resolution aiming to detect alpha-dust (Contract research); FY2018 Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development

Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*

JAEA-Review 2019-038, 57 Pages, 2020/03

JAEA-Review-2019-038.pdf:4.6MB

JAEA/CLADS, had been conducting the Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development (hereafter referred to "the Project") in FY2018. The Project aims to contribute to solving problems in nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. Among the adopted proposals in FY2018, this report summarizes the research results of the "Development of Imaging System with Ultra-high Spatial Resolution Aiming to Detect Alpha-dust". In the present study, we have developed a prototype of a system aiming to elucidate the behavior of alpha-dust generated at the time of debris retrieval. In this system, alpha-ray is first converted to visible light by novel scintillator. Then, imaging with ultra-high resolution will be possible using a lens and an Si-semiconductor camera (CMOS camera). Also, it will be possible to identify the species of alpha-ray emitting nuclides by unfolding of the spectra. The demonstration tests of the system will be conducted for dust samplers at the Plutonium Fuel Development Center, JAEA. In the development of the present system, it is important to use scintillator whose emission wavelength is sensitive to the CMOS camera as well as high emission scintillator. Considering these conditions, the key technology will be the improvement of the purity of crystals and optimization of the shapes of the materials including powers.

JAEA Reports

Development of technology to prevent scattering of radioactive materials in fuel debris retrieval (Contract research); FY2018 Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development

Collaborative Laboratories for Advanced Decommissioning Science; The University of Tokyo*

JAEA-Review 2019-037, 90 Pages, 2020/03

JAEA-Review-2019-037.pdf:7.0MB

JAEA/CLADS, had been conducting the Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development (hereafter referred to "the Project") in FY2018. The Project aims to contribute to solving problems in nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2018, this report summarizes the research results of the "Development of Technology to Prevent Scattering of Radioactive Materials in Fuel Debris Retrieval". The objective of the present study is to clarify the behavior of microparticles in gas and liquid phases in order to steadily confine radioactive microparticles at the time of debris retrieval in Fukushima Daiichi Nuclear Power Station. In addition, as measures to prevent scattering, we will evaluate and develop methods by experiments and simulation as to; (1) a method to suppress the scattering with minimum amount of water utilizing water spray etc., and (2) a method to suppress the scattering by solidifying fuel debris.

Journal Articles

Simulation study on the design of nondestructive measurement system using fast neutron direct interrogation method to nuclear materials in fuel debris

Maeda, Makoto; Furutaka, Kazuyoshi; Kureta, Masatoshi; Ozu, Akira; Komeda, Masao; Toh, Yosuke

Journal of Nuclear Science and Technology, 56(7), p.617 - 628, 2019/07

 Times Cited Count:1 Percentile:23.13(Nuclear Science & Technology)

JAEA Reports

Technical design of the pressure-resistant chamber for open inspections of the storage containers of nuclear fuel materials

Marufuji, Takato; Sato, Takumi; Ito, Hideaki; Suzuki, Hisashi; Fujishima, Tadatsune; Nakano, Tomoyuki

JAEA-Technology 2019-006, 22 Pages, 2019/05

JAEA-Technology-2019-006.pdf:2.84MB

Radioactive contamination incident occurred at Plutonium Fuel Research Facility (PFRF) in Oarai Research and Development Institute, Japan Atomic Energy Agency on June 6, 2017. During inspection work of storage container containing nuclear fuel materials, the PVC bag packaging in the storage container ruptured when a worker opened the lid in the hood, and a part of contents was spattered over the room. The cause of the increase of internal pressure of the storage container was gas generation by alpha radiolysis of the epoxy resin mixed with nuclear fuel materials. Opening inspection of about 70 similar containers stored in PFRF has been planned to confirm the condition of the contents and to stabilize the stored materials containing organic compounds. For safe and reliable open inspection of the storage containers with high internal pressure in the glove box, it is necessary to develop a pressure-resistant chamber in which the storage containers are opened and the contents are inspected under gastight condition. This report summarizes the concerns and countermeasures of the chamber design and the design results of the chamber.

JAEA Reports

Progress report on Nuclear Safety Research Center (JFY 2015 - 2017)

Nuclear Safety Research Center, Sector of Nuclear Safety Research and Emergency Preparedness

JAEA-Review 2018-022, 201 Pages, 2019/01

JAEA-Review-2018-022.pdf:20.61MB

Nuclear Safety Research Center (NSRC), Sector of Nuclear Safety Research and Emergency Preparedness, Japan Atomic Energy Agency (JAEA) is conducting technical support to nuclear safety regulation and safety research based on the Mid-Long Term Target determined by Japanese government. This report summarizes the research structure of NSRC and the cooperative research activities with domestic and international organizations as well as the nuclear safety research activities and results in the period from JFY 2015 to 2017 on the nine research fields in NSRC; (1) severe accident analysis, (2) radiation risk analysis, (3) safety of nuclear fuels in light water reactors (LWRs), (4) thermohydraulic behavior under severe accident in LWRs, (5) materials degradation and structural integrity, (6) safety of nuclear fuel cycle facilities, (7) safety management on criticality, (8) safety of radioactive waste management, and (9) nuclear safeguards.

Journal Articles

Study on restricted use of contaminated rubble on Fukushima Daiichi NPS site, 2; Validation of reference radiocesium concentration for recycling materials

Miwa, Kazuji; Shimada, Taro; Takeda, Seiji

Progress in Nuclear Science and Technology (Internet), 6, p.166 - 170, 2019/01

In this study, in order to validate the restricted use of recycling material at the reference radiocesium concentration (determined in series report (1)), we evaluated worker annual doses, air dose rate at the site boundary and impact of migrated radiocesium into groundwater. Firstly, we evaluated the additional annual dose for workers, on the assumption that typical workers coming in contact with the source after construction (Road: 1.2 mSv/y, Building: 1.3 mSv/y). Secondly, we evaluated the air dose rates by distance from road and building including recycling material, and investigated the distance for not exceeding 1 mSv/y (including additional dose rate by recycling and background dose rate of 0.6 mSv/y) at the site boundary (Road: 25 m, Building: 1 m). Thirdly, we evaluated the Cs migration in groundwater, and investigated the distance required for satisfying the operation target value ($$^{134}$$Cs: 1 Bq/L, $$^{137}$$Cs: 1 Bq/L) at the boundary (coastal line) (Road: 10 m, Building: 10 m).

Journal Articles

Shielding

Maekawa, Fujio

Hamon, 28(4), p.208 - 211, 2018/11

Adequate shielding of neutrons and associated $$gamma$$-rays is of importance from viewpoints of the radiation safety of researchers and good experimental data taking by reducing the background. This article introduces basics of neutron shielding, physics and suitable materials for neutron and $$gamma$$-ray shielding, and an example of conceptual shielding design for the 1-MW spallation neutron source of J-PARC MLF.

Journal Articles

Development of experimental technology for simulated fuel-assembly heating to address core-material-relocation behavior during severe accident

Abe, Yuta; Yamashita, Takuya; Sato, Ikken; Nakagiri, Toshio; Ishimi, Akihiro; Nagae, Yuji

Proceedings of 26th International Conference on Nuclear Engineering (ICONE-26) (Internet), 9 Pages, 2018/07

Journal Articles

Development of delayed gamma-ray spectroscopy for nuclear material analysis

Rodriguez, D.; Rossi, F.; Takahashi, Tone; 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

JAEA Reports

Cutting operation of simulated fuel assembly heating examination by AWJ

Abe, Yuta; Nakagiri, Toshio; Watatani, Satoshi*; Maruyama, Shinichiro*

JAEA-Technology 2017-023, 46 Pages, 2017/10

JAEA-Technology-2017-023.pdf:8.01MB

This is a report on Abrasive Water Jet (AWJ) cutting work carried out on specimen, which was used for Simulated Fuel Assembly Heating Examination by Collaborative Laboratories for Advanced Decommissioning Science (CLADS) molten core behavior analysis group in February 2016. The simulated fuel assembly is composed of Zirconia for the outer crucible/simulated fuel, stainless steel for the control blade and Zircaloy (Zr) for the cladding tube/channel box. Therefore, it is necessary to cut at once substances having a wide range of fracture toughness and hardness. Moreover, it is a large specimen with an approximate size of 300 mm. In addition, epoxy resin has high stickiness, making it more difficult to cut. Considering these effects, AWJ cutting was selected. The following two points were devised, and this specimen could be cut with AWJ. If it was not possible to cut at one time like a molten portion of boride, it was repeatedly cut. By using Abrasive Suspension Jet (ASJ) system with higher cutting ability than Abrasive Injection Jet (AIJ, conventional method) system, cutting time was shortened. As a result of this work, the cutting method in Simulated Fuel Assembly Heating Examination was established. Incidentally, in the cutting operation, when the cutting ability was lost at the tip of the AWJ, a curved cut surface, which occurs when the jet flowed away from the feeding direction, could be confirmed at the center of the test body. From the next work, to improve the cutting efficiency, we propose adding a mechanism such as turning the cutting member itself for re-cutting from the exit side of the jet and appropriate traverse speed to protect cut surface.

Journal Articles

Evaluation and demonstration of cutting the fuel assembly heating examination by AWJ

Maruyama, Shinichiro*; Watatani, Satoshi*

Mitsui Sumitomo Kensetsu Gijutsu Kenkyu Kaihatsu Hokoku, (15), p.107 - 112, 2017/10

It is essential to estimate characteristics and forms of fuel debris for safe and reliable removing at the decommissioning of the Fukushima Daiichi Nuclear Power Plant (1F). For the estimation, melting behavior of fuel assembly in the accident is being researched. To proceed the research, the fuel debris were need to cut, and the abrasive water jet (AWJ) which had enough results for cutting ceramic material or mixed material of zirconium alloy and stainless. The test results demonstrated that AWJ could cut the fuel assembly and accumulated the cutting data which will be subservient when removing the fuel debris in future.

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, 146, p.09018_1 - 09018_4, 2017/09

 Times Cited Count:3 Percentile:92.06

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

Development of non-transfer type plasma heating technology to address CMR behavior during severe accident with BWR design conditions

Abe, Yuta; Sato, Ikken; Nakagiri, Toshio; Ishimi, Akihiro; Nagae, Yuji

Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 7 Pages, 2017/04

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

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