Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 1173

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

JAEA Reports

Study on degradation of fuel debris by combined effects of radiological, chemical and biological functions (Contract research); FY2019 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Tokyo Institute of Technology*

JAEA-Review 2020-046, 69 Pages, 2021/01

JAEA-Review-2020-046.pdf:4.81MB

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 "Study on Degradation of Fuel Debris by Combined Effects of Radiological, Chemical, and Biological Functions". In the project, radiochemists, nuclear chemists, nuclear physicists, material scientists, and environmental biologists are teamed to elucidate the mechanism of the degradation of fuel debris by combined effects of radiological, chemical, and biological Functions. In FY2019, the members of the project team focused on literature survey, preliminary experiments, and installation of experimental devices for the planned research.

JAEA Reports

Development of the technology for preventing radioactive particles' dispersion during the fuel debris retrieval (Contract research); FY2019 Nuclear Energy Science & Technology and Human Resource Development Project

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

JAEA-Review 2020-043, 116 Pages, 2021/01

JAEA-Review-2020-043.pdf:7.74MB

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 FY2018, this report summarizes the research results of the "Development of the technology for preventing radioactive particles' dispersion during the fuel debris retrieval" conducted in FY2019. In this study, a technique to effectively suppress the scattering of fine particles has been developed, and as a result of experiments, a method of spraying with water mist was found to be an effective and applicable method for improving aerosol removal efficiency and removal rate. As a method of solidifying fuel debris to suppress fine particle scattering during cutting, geopolymer was evaluated for its strength, thermal conductivity and cutting powder. In addition, flow status of geopolymer and the temperature distribution inside RPV covered by geopolymer were simulated.

JAEA Reports

Fluorination method for classification of the waste generated by fuel debris removal (Contract research); FY2019 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Hitachi-GE Nuclear Energy*

JAEA-Review 2020-034, 155 Pages, 2021/01

JAEA-Review-2020-034.pdf:10.77MB

JAEA/CLADS had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project in FY2019. Among the adopted proposals in FY2019, this report summarizes the research results of the "Fluorination Method for Classification of the Waste Generated by Fuel Debris Removal" conducted in FY2019.

JAEA Reports

Basic research on the stability of fuel debris including alloy phase (Contract research); FY2019 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*

JAEA-Review 2020-032, 97 Pages, 2021/01

JAEA-Review-2020-032.pdf:4.16MB

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 FY2018, this report summarizes the research results of the "Basic Research on the Stability of Fuel Debris Including Alloy Phase" conducted in FY2019. In the present study, we focus on fuel debris consisting of oxide phase and alloy phase generated by the high-temperature chemical reaction between structure materials (SUS pipes, pressure vessels, etc.) and fuels (melted fuels, claddings components, etc.). We synthesize the simulated debris of UO$$_{2}$$-SUS system and UO$$_{2}$$-Zr(ZrO$$_{2}$$)-SUS system by high-temperature heat treatment, and measure their chemical property and dissolution behavior in water. Also, we will conduct research and development to spectroscopically analyze secular changes of oxide phase and alloy phase in the simulated debris.

Journal Articles

Derivation of ideal power distribution to minimize the maximum kernel migration rate for nuclear design of pin-in-block type HTGR

Okita, Shoichiro; Fukaya, Yuji; Goto, Minoru

Journal of Nuclear Science and Technology, 58(1), p.9 - 16, 2021/01

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

Suppressing the kernel migration rates, which depend on both the fuel temperature and the fuel temperature gradient, under normal operation condition is quite important from the viewpoint of the fuel integrity for High Temperature Gas-cooled Reactors. The presence of the ideal axial power distribution to minimize the maximum kernel migration rate allows us to improve efficiency of design work. Therefore, we propose a new method based on Lagrange multiplier method in consideration of thermohydraulic design in order to obtain the ideal axial power distribution to minimize the maximum kernel migration rate. For one of the existing conceptual designs performed by JAEA, the maximum kernel migration rate for the power distribution to minimize the maximum kernel migration rate proposed in this study is lower by approximately 10% than that for the power distribution as a conventional design target to minimize the maximum fuel temperature.

JAEA Reports

Improvement of critical safety technology in fuel debris retrieval (Contract research); FY2019 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Tokyo Institute of Technology*

JAEA-Review 2020-041, 30 Pages, 2020/12

JAEA-Review-2020-041.pdf:1.9MB

JAEA/CLADS had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project in FY2019. Among the adopted proposals in FY2019, this report summarizes the research results of the "Improvement of Critical Safety Technology in Fuel Debris Retrieval" conducted in FY2019.

JAEA Reports

Development of hydrogels for prevention of radioactive dust dispersion during fuel debris retrieval (Contract research); FY2019 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Osaka University*

JAEA-Review 2020-030, 55 Pages, 2020/12

JAEA-Review-2020-030.pdf:2.76MB

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 FY2018, this report summarizes the research results of the "Development of hydrogels for prevention of radioactive dust dispersion during fuel debris retrieval" conducted in FY2019. In this study, we propose coating fuel debris with thixotropic gel materials to suppress dust dispersion during debris retrieval. Hectorite clay mineral - borax composite gel was selected based on the viscosity, the transparency and the radiation resistance. Simulated cutting tests confirm that the gel coating effectively suppress the dust dispersion.

JAEA Reports

Effect of nitrogen oxides on decomposition behavior of gaseous ruthenium tetroxide

Yoshida, Naoki; Amano, Yuki; Ono, Takuya; Yoshida, Ryoichiro; Abe, Hitoshi

JAEA-Research 2020-014, 33 Pages, 2020/12

JAEA-Research-2020-014.pdf:3.66MB

Considering the boiling and drying accident of high-level liquid waste in fuel reprocessing plant, Ruthenium (Ru) is an important element. It is because Ru would form volatile compounds such as ruthenium tetroxide (RuO$$_{4}$$) and could be released into the environment with other coexisting gasses such as nitric oxides (NOx) such as nitric oxide (NO) and nitrogen dioxide (NO$$_{2}$$). To contribute to the safety evaluation of this accident, we experimentally evaluated the effect of NOx on the decomposition and chemical change behavior of the gaseous RuO$$_{4}$$ (RuO$$_{4}$$(g)). As a result, the RuO$$_{4}$$(g) decomposed over time under the atmospheric gasses with NO or NO$$_{2}$$, however, the decomposition rate was slower than the results of experiments without NOx. These results showed that the NOx stabilized RuO$$_{4}$$(g).

Journal Articles

Evaluation of breach characteristics of fast reactor fuel pins during steady state irradiation

Oka, Hiroshi*; Kaito, Takeji; Ikusawa, Yoshihisa; Otsuka, Satoshi

Nuclear Engineering and Design, 370, p.110894_1 - 110894_8, 2020/12

The objective of this study is to evaluate the reliability of a cumulative damage fraction (CDF) analysis for the prediction of fuel pin breach in fast rector using experimentally obtained fuel pin breach data for the first time. Six breached fuel pins were obtained from steady state irradiation in the EBR-II. Post irradiation examinations revealed that FP gas pressure was the main cause of creep damage in cladding, and that the stress contribution from FCMI was negligible. CDFs evaluated for these pins using in-reactor creep rupture equation, taking into account the irradiation history of cladding temperature and hoop stress due to FP gas pressure, were in the range of 0.7 to 1.4 at the occurrence of breach. This shows clearly that fuel pin breach occurs when the CDF approaches 1.0. The results indicate that CDF analysis would be a reliable method for the prediction of fuel pin breach when appropriate material strength and environmental effects are adopted.

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.

Journal Articles

Adsorption behavior of cesium on hybrid microcapsules in spent fuel solution

Onishi, Takashi; Koyama, Shinichi; Mimura, Hitoshi*

Nippon Ion Kokan Gakkai-Shi, 31(3), p.43 - 49, 2020/10

Journal Articles

Pressure resistance thickness of disposal containers for spent fuel direct disposal

Sugita, Yutaka; Taniguchi, Naoki; Makino, Hitoshi; Kanamaru, Shinichiro*; Okumura, Taisei*

Nippon Genshiryoku Gakkai Wabun Rombunshi, 19(3), p.121 - 135, 2020/09

A series of structural analysis of disposal containers for direct disposal of spent fuel was carried out to provide preliminary estimates of the required pressure resistance thickness of the disposal container. Disposal containers were designed to contain either 2, 3 or 4 spent fuel assemblies in linear, triangular or square arrangements, respectively. The required pressure resistance thickness was evaluated using separation distance of the housing space for each spent fuel assembly as a key model parameter to obtain the required thickness of the body and then the lid of the disposal container. This work also provides additional analytical technical knowledge, such as the validity of the setting of the stress evaluation line and the effect of the model length on the analysis. These can then be referred to and used again in the future as a basis for conducting similar evaluations under different conditions or proceeding with more detailed evaluations.

JAEA Reports

Report of summer holiday practical training 2019; Feasibility study on nuclear battery using HTTR core; Feasibility study for nuclear design, 2

Ishitsuka, Etsuo; Nakashima, Koki*; Nakagawa, Naoki*; Ho, H. Q.; Ishii, Toshiaki; Hamamoto, Shimpei; Takamatsu, Kuniyoshi; Kenzhina, I.*; Chikhray, Y.*; Matsuura, Hideaki*; et al.

JAEA-Technology 2020-008, 16 Pages, 2020/08

JAEA-Technology-2020-008.pdf:2.98MB

As a summer holiday practical training 2019, the feasibility study for nuclear design of a nuclear battery using HTTR core was carried out, and the $$^{235}$$U enrichment and burnable poison of the fuel, which enables continuous operation for 30 years with thermal power of 5 MW, were studied by the MVP-BURN. As a result, it is clear that a fuel with $$^{235}$$U enrichment of 12%, radius of burnable poison and natural boron concentration of 1.5 cm and 2wt% are required. As a next step, the downsizing of core will be studied.

Journal Articles

Transient response of LWR fuels (RIA)

Udagawa, Yutaka; Fuketa, Toyoshi*

Comprehensive Nuclear Materials, 2nd Edition, Vol.2, p.322 - 338, 2020/08

Journal Articles

Advanced concepts in TRISO fuel

Minato, Kazuo; Ogawa, Toru

Comprehensive Nuclear Materials, 2nd Edition, Vol.5, p.334 - 360, 2020/08

TRISO coated particle fuel has been developed for the high temperature gas-cooled reactors, which consists of microspherical fuel kernel and coating layers of pyrolytic carbon and silicon carbide. To improve the high temperature stability, the resistance to the chemical attack by fission products and the retention of fission products of the TRISO coated particle fuels, several types of advanced fuels were proposed and tested. Coated particle fuels for fast reactors were also proposed and tested. In this paper, fuel designs, fabrications, characterization techniques and fuel performance of these advanced coated particle fuels are systematically described. This is the updated version of the paper having the same title in Comprehensive Nuclear Materials published in 2012.

Journal Articles

A Linear Equation of characteristic time profile of power in subcritical quasi-steady state

Yamane, Yuichi

Journal of Nuclear Science and Technology, 57(8), p.926 - 931, 2020/08

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

An equation of power in subcritical quasi-steady state has been derived based on one-point kinetics equations for the purpose of utilizing it for the development of timely reactivity estimation from complicated time profile of neutron count rate. It linearly relates power, $$P$$, to a new variable $$q$$, which is a function of time differential of the power. It has been confirmed by using one-point kinetics code, AGNES, that the calculated points ($$q, P$$) are perfectly in a line described by the new equation and that points ($$q, P$$) calculated from transient subcritical experiments by using TRACY made a line with a slope indicated by the new equation.

Journal Articles

Mechanical and thermal properties of Zr-B and Fe-B alloys

Sun, Y.*; Abe, Yuta; Muta, Hiroaki*; Oishi, Yuji*

Journal of Nuclear Science and Technology, 57(8), p.917 - 925, 2020/08

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

Journal Articles

Numerical simulation of liquid jet behavior in shallow pool by interface tracking method

Suzuki, Takayuki*; Yoshida, Hiroyuki; Horiguchi, Naoki; Yamamura, Sota*; Abe, Yutaka*

Proceedings of 2020 International Conference on Nuclear Engineering (ICONE 2020) (Internet), 7 Pages, 2020/08

JAEA Reports

Basis for handling of nuclear fuel materials (Second edition)

Task Force on Writing Textbook of Nuclear Fuel Materials

JAEA-Review 2020-007, 165 Pages, 2020/07

JAEA-Review-2020-007.pdf:6.63MB

The present textbook was written by Task Force on Writing Textbook of Nuclear Fuel Materials at the Nuclear Science Research Institute in order to improve technological abilities of engineers and researchers who handle nuclear fuel materials. The taskforce consists of young and middle class engineers each having certification for chief engineer of nuclear fuel. The present textbook mainly deals with uranium and plutonium, and shows their nuclear properties, physical and chemical properties, and radiation effects on materials and human body. It also presents basic matters for safety handling of nuclear fuel materials, such as handling of nuclear fuel materials with hood and glovebox, important points in storage and transportation of nuclear fuel materials, radioactive waste management, radiation safety management, and emergency management. Furthermore, incident cases at domestic and foreign nuclear fuel materials facilities are compiled to learn from the past.

Journal Articles

Four-point-bend tests on high-burnup advanced fuel cladding tubes after exposure to simulated LOCA conditions

Narukawa, Takafumi; Amaya, Masaki

Journal of Nuclear Science and Technology, 57(7), p.782 - 791, 2020/07

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

1173 (Records 1-20 displayed on this page)