Ono, Masato; Hanawa, Yoshio; Sonobe, Hiroshi; Nishimura, Arashi; Sugaya, Naoto; Iigaki, Kazuhiko
JAEA-Technology 2020-010, 14 Pages, 2020/09
In response to new standard for regulating research and test reactor which is enforced December 18, 2013, it was carried out assessment of the probability of aircraft crashing for HTTR. According to assessment method provided in the Assessment Criteria of the Probability of Aircraft Crashing on Commercial Power Reactor Facilities, assessment was conducted targeting reactor building, spent fuel storage building and cooling tower. As a result, it was confirmed that the probability was 5.9810, which is lower than the assessment criteria 10.
Nishiyama, Yutaka; Iwai, Masaki; Chiba, Yusuke; Tsubaki, Hirohiko; Ono, Hayato*; Hayasaka, Toshiro*; Hanyu, Toshinori*
JAEA-Technology 2020-007, 18 Pages, 2020/09
Maintenance and Operation Section for Remote Control Equipment in Naraha Center for Remote Control Technology Development is the main part of the nuclear emergency response team of Japan Atomic Energy Agency (JAEA) in full-scale operation starts on the 1st of April, 2020. The section needs to develop equipment for JAEA nuclear emergency. Because of dealing the full-scale operation, the section designed and produced two sets of Multi-joint Manipulator or (for Opening Doors) against Nuclear Disaster in order to put them on two crawler robots in 2018 fiscal year. And the section also designed and produced a Crawler Robot for Opening and Closing Manual Valves in 2019 fiscal year. This report shows two sets of Multi-Joint Manipulator (for Opening Doors) and a Crawler Robot for Opening and Closing Manual Valves designed and produced by Maintenance and Operation Section for Remote Control Equipment in 2018 and 2019 fiscal year.
Togawa, Orihiko; Hayakawa, Tsuyoshi; Tanaka, Tadao; Yamamoto, Kazuya; Okuno, Hiroshi
JAEA-Review 2020-017, 36 Pages, 2020/09
In 2010, the government of Japan joined the Response and Assistance Network (RANET) of the International Atomic Energy Agency (IAEA), in order to contribute to offering international assistance in the case of a nuclear accident or radiological emergency. At that occasion, the Japan Atomic Energy Agency (JAEA) was registered as the National Assistance Capability (NAC) having resources capable of the External Based Support (EBS) in the following seven areas: (1) aerial survey, (2) radiation monitoring, (3) environmental measurements, (4) assessment and advice, (5) internal dose assessment, (6) bioassay and (7) dose reconstruction. After the registration, three inquiries were directed to the JAEA about a possibility of its support. However, the JAEA's assistance has not eventually been realized. On the other hand, the JAEA participated almost every year in the international Convention Exercise (ConvEx) carried out by the IAEA in connection with RANET. This report describes an outline of the RANET and related activities of the JAEA for RANET registration and participation in the ConvEx.
Asakura, Kazuki; Shimomura, Yusuke; Donomae, Yasushi; Abe, Kazuyuki; Kitamura, Ryoichi
JAEA-Review 2020-015, 66 Pages, 2020/09
The disposal of radioactive waste from the research facility need to calculated from the radioactivity concentration that based on variously nuclear fuels and materials. In Japan Atomic Energy Oarai Research and Development Institute, the study on considering disposal is being advanced among the facilities which generate radioactive waste as well as the facilities which process radioactive waste. This report summarizes a study result in FY2019 about the evaluation method to determine the radioactivity concentration in radioactive waste on Oarai Research and Development Institute.
JAEA-Review 2020-014, 63 Pages, 2020/09
J-PARC Center has been promoting several public relations activities to appeal the cutting-edge research programs and their outputs to the citizen, especially in Ibaraki prefecture and Tokai village. The Public Relations Section put weight to outreach events as the best tool for this purpose, such as site tour, open house, and summer school. Here the outreach activities are summarized mainly from FY2012 to FY2019.
JAEA-Review 2020-006, 261 Pages, 2020/09
A literature review was conducted on the increase in surface area of vitrified products of HLW due to the fracturing caused by cooling during glass pouring process and by mechanical impact, from the perspective of a parameter of the radionuclide release model in the performance assessment of geological disposal system studied overseas. The review was focused on the value of surface area increase factor set as a parameter in the model, the experimental work to evaluate an increase in surface area, and how the parameters on surface area were determined based on the experimental results. The surface area obtained from the experiments executed in Japan was also discussed in comparison with the overseas studies. On the basis of the investigation, the effects of various conditions on the surface area were studied, such as a diameter of vitrified product, cooling condition during and after the glass pouring, impact on vitrified products during their handling, environment after the closure of disposal facility, and others. The causes of fracturing are associated with the phenomena or events in the waste management process such as production, transport, storage, and disposal. The surface area increase factors set in the nuclide release model of the glass and their bases were reviewed. In addition, the measured values and the experimental methods for surface increase factors published so far were compared. Accordingly, the methods for measuring surface area as the bases were identified for these factors set in the models. The causes of fracturing and features of these factors were studied with respect to the relation with the waste management process. The results from the review and assessment can contribute to the expanding the knowledge for the conservative and realistic application of these factors to performance assessment, and to the developing and upgrading of safety case as a consequence.
Nagai, Takayuki; Okamoto, Yoshihiro; Yamagishi, Hirona*; Ota, Toshiaki*; Kojima, Kazuo*; Inose, Takehiko*; Sato, Seiichi*; Hatakeyama, Kiyoshi*
JAEA-Research 2020-009, 48 Pages, 2020/09
The local structure of glass-forming elements and waste elements in waste glass varies with its chemical composition. In this study, borosilicate glass frit and simulated waste glass samples were prepared and the local structure and chemical state regarding boron (B), oxygen (O), and waste elements of cerium (Ce), cesium (Cs) were estimated by using XAFS measurement in soft X-ray region. Following results were obtained by XAFS measurements of prepared glass frit and simulated waste glass samples: (1) The existence ratio of four coordinate sp structure (BO) tends to increase with increasing NaO content in glass samples. (2) The height of a pre-edge which appears by K-edge XANES spectrum of O is so high that the Fe content in glass samples. Following results were obtained by XAFS measurements of simulated waste glass samples after immersion test to investigate long chemical stability. (1) The existence ratio of four coordinate sp structure (BO) increases by immersion test. (2) Ce which exists in the surface layer is oxidized by immersion test, and much of Cs in surface layer is lost after leach testing. Even if the glass frit form (fiber cartridge or beads) and manufacturing method were changed and a glass sample of the similar chemical composition was prepared, these observed Raman spectra of samples were different.
Morita, Yasuji; Fukushima, Masahiro; Kashima, Takao*; Tsubata, Yasuhiro
JAEA-Data/Code 2020-013, 38 Pages, 2020/09
Critical Masses of Cm, Am and the mixture were calculated in metal-water mixtures with water reflector as a basic data for criticality safety assessment of minor actinide separation process. In the mixture of Cm-244 and Cm-245, higher ratio of Cm-245 gives smaller critical mass, but the amount of Cm-245 in the critical mass can be obtained by concentration of Cm-245 in the Cm mixture without depending on the Cm-245 ratio. Critical mass of Cm isotope mixture with 30% Cm-245 was smaller than that of Pu isotope mixture in the practical reprocessing (71% Pu-239 + 17% Pu-240 + 12% Pu-241). When Cm is separated from other element including Am and the solution is concentrated, measure for the critical accident has to be taken. Critical mass of Am-242m is smaller than that of Cm-245, but the ratio of Am-242m in the Am contained in practical spent fuel is small enough, about several percent, and therefore the critical accident by Am does not have to be considered. That by the mixture of Am and Cm does not either.
Sugaya, Naoto; Okada, Yuji; Nishimura, Arashi; Sonobe, Hiroshi; Kimura, Nobuaki; Kimura, Akihiro; Hanawa, Yoshio; Nemoto, Hiroyoshi
JAEA-Testing 2020-004, 67 Pages, 2020/08
In the Japan Materials Testing Reactor (JMTR), the leakage accidents of radioactive waste liquid were occurred from the tanks and pipes of the liquid waste disposal facility in the JMTR tank-yard building in JFY2014. In order to respond to the accident, the tanks and pipes were replaced from JFY2016 to 2019. On the other hand, a lot of cracks were occurred on the concreate wall of the tank-yard building when the frame structure supports were fixed to the concrete wall in the replacement work. Thus, it is necessary to repair the concreate wall of the tank-yard building. Especially, some cracks with swelling (cone-shaped fracture) were raised around some anchor bolts (the post-installed chemical anchor bolts) fixed the frame structure supports. The repairing method for the cone-shaped fracture of the concrete wall is standardized, but there was no reference value of tensile strength for the validation of the post-installed chemical anchor bolts after the repairing method. In this report, the repairing method was selected for the cone-shaped fracture on the concreate wall and the reference value of tensile strength for the validation of the post-installed chemical anchor bolts by this repairing method. The mock-ups for repairing cone-shaped fracture were fabricated by the selected repairing method and the tensile tests of the post-installed chemical anchor bolts were performed. From the results, the validation of the repairing method was obtained in this test and it was obvious the repairing of cone-shaped fracture is preferable method for the concreate wall of the JMTR tank-yard building.
Nakamura, Satoshi; Kimura, Takahiro; Ban, Yasutoshi; Tsubata, Yasuhiro; Matsumura, Tatsuro
JAEA-Technology 2020-009, 22 Pages, 2020/08
Partitioning and transmutation technology division is planning to measure fission rate ratios that contribute to validate nuclear data of minor actinides (MA). For this purpose, MA sources for fission chambers were prepared using electrodeposition method. The radioactivity of each MA source was quantified, and its uncertainty was evaluated. Seven types of MA sources with different radioactivity were prepared using four nuclides of Np, Am, Am, and Cm. A Cm source solution of which radioactivity was quantified by isotope dilution method was used to prepare working standard sources of Cm. The radioactivities were quantified as 1461 Bq, 2179 Bq, and 2938 Bq for Np sources, 1.428 MBq for Am source, 370.5 kBq and 89.57 kBq for Am sources, and 2.327 MBq for Cm source with, the uncertainty of 0.35% (1). This report summarizes the method for preparation and quantification of MA sources, and uncertainty evaluation.
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
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 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 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.
Nishiyama, Yutaka; Iwai, Masaki; Tsubaki, Hirohiko; Chiba, Yusuke; Hayasaka, Toshiro*; Ono, Hayato*; Hanyu, Toshinori*
JAEA-Technology 2020-006, 26 Pages, 2020/08
Maintenance and Operation Section for Remote Control Equipment in Naraha Center for Remote Control Technology Development is the main part of the nuclear emergency response team of JAEA deal with Act on Special Measures Concerning Nuclear Emergency Preparedness. The section needs to remodel crawler-type robots for tasks, crawler-type scouting robots, and so on. About two crawler-type robots for tasks, the section designed and mounted advanced wireless communication equipment on manipulators mounted on the two robots. The crawler part of the robot has been able to be controlled by way of the new equipment, and when it is broken down, it can be changed by way of an original equipment. And the new equipment makes a single relay robot controllable both the crawler part and the manipulator part of the robot, in case of wireless relay robots being needed. And after checking the ability and characteristic about 5 wireless communication equipment, the section chose and mounted the best equipment on one crawler-type scouting robot. This report shows design and mounting advanced wireless communication equipment on the two crawler-type robots for tasks and on the one crawler-type scouting robot.
Nishio, Kazuhisa*; Shimizu, Mayuko; Iyatomi, Yosuke; Hama, Katsuhiro
JAEA-Review 2020-013, 59 Pages, 2020/08
The Tono Geoscience Center (TGC) of Japan Atomic Energy Agency (JAEA) has been conducting geoscientific study in order to establish a scientific and technological basis for the geological disposal of HLW. Technical information of the result on the geoscientific study conducted at TGC is provided at the annual Information and Opinion Exchange Conference on Geoscientific Study of TGC for exchanging opinions among researchers and engineers from universities, research organizations and private companies. This document compiles the research presentations and posters of the conference in Mizunami on November 20, 2019.
Department of Decommissioning and Waste Management
JAEA-Review 2020-012, 103 Pages, 2020/08
This report describes the activities of Department of Decommissioning and Waste Management (DDWM) in Nuclear Science Research Institute (NSRI) in the period from April 1, 2018 to March 31, 2019. The report covers organization and missions of DDWM, outline and operation/maintenance of facilities which belong to DDWM, treatment and management of radioactive wastes, decommissioning activities, and related research and development activities which were conducted in DDWM.
Sector of Fast Reactor and Advanced Reactor Research and Development
JAEA-Evaluation 2020-001, 128 Pages, 2020/08
Japan Atomic Energy Agency consulted with the "Evaluation Committee of Research Activities for High Temperature Gas-cooled Reactor (hereinafter referred to as "HTGR") and Related Hydrogen Production Technology" (hereinafter referred to as "Evaluation Committee"), which consists of specialists in the fields of the evaluation subjects of high temperature gas-cooled reactor and related heat application technology, for interim assessment in the 3rd Mid-and Long-Term Plan about the relevance of the management and research activities of the HTGR and related application technology during the period from April 2017 to March 2020. As a result, three members of the Evaluation Committee concluded a score of "S", and seven members of the Evaluation Committee concluded a score of "A". The interim assessment to research and development activities from April 2017 to March 2020 was concluded a score of "A". In addition, the Evaluation Committee recommended that the judgement to move to the construction phase of the HTTR-heat utilization test plant be made after 2 years, after the HTTR will be restarted and the thermal load fluctuation tests using HTTR will be carried out. This report lists the members of the Evaluation Committee and outlines the assessment item and the review process for procedure of the assessment. The assessment report which was issued by the Evaluation Committee is attached.
Onoe, Hironori; Takeuchi, Ryuji
JAEA-Data/Code 2020-008, 41 Pages, 2020/08
Japan Atomic Energy Agency (JAEA) has been conducting a wide range of geoscientific research in order to build scientific and technological basis for geological disposal of nuclear wastes. This study aims to establish comprehensive techniques for the investigation, analysis and assessment of the deep geological environment in fractured crystalline rock. The Regional Hydrogeological Study (RHS) project is a one of the geoscientific research program at Tono Geoscience Center. This project started since April 1992 and main investigations were finished to FY2004. Since FY2005, hydrogeological and hydrochemical monitoring have been continued using the existing monitoring system. Furthermore, these monitoring were ceased at the end of FY2019 due to the completion of the RHS project. This report describes the results of the long term hydro-pressure monitoring for FY2019.
Aono, Ryuji; Mitsukai, Akina; Haraga, Tomoko; Ishimori, Kenichiro; Kameo, Yutaka
JAEA-Data/Code 2020-006, 70 Pages, 2020/08
Radioactive wastes which generated from research and testing reactors in Japan Atomic Energy Agency are planning to be buried at the near surface disposal field. Therefore, it is required to establish the method to evaluate the radioactivity concentrations of radioactive wastes by the time it starts disposal. In order to contribute to this work, we collected and analyzed the samples generated from JPDR and JRR-4. In this report, we summarized the radioactivity concentrations of 19 radionuclides (H, C, Cl, Co, Ni, Sr, Nb, Tc, Ag, I, Cs, Eu, Eu, U, U, Pu, Pu, Am, Cm) which were obtained from radiochemical analysis of those samples.
Abe, Tomohisa; Ogiya, Takashi*; Shibata, Katsuya*; Hanawa, Tatsuaki*; Sanada, Yukihisa
JAEA-Data/Code 2020-004, 280 Pages, 2020/08
After the accidents at Fukushima Daiichi Nuclear Power Station (FDNPS), Japan Atomic Energy Agency has carried on survey for distribution situation of radiation materials under the direction of the Ministry of Education, Culture, Sports, Science and Technology (later the Nuclear Regulatory Agency) from June 2011 to FY2019. This report is mainly summarized as data-base of air dose rate, integrated dose and radionuclide concentration of some types of environmental sample (airborne dust, soil, pine needles) in the radiation monitoring in Fukushima Prefecture (20 km far from FDNPS). The results of radiation monitoring were analyzed for temporal change at each measurement site under the unification format. Furthermore, the effective half-life and the dispersion at each location and sample were evaluated based on these big data.
Sakashita, Koichi; Ishii, Naoyuki; Kijima, Jun; Aoyagi, Yoshitaka; Hagiwara, Masayoshi; Fukushima, Mineo
JAEA-Testing 2020-003, 20 Pages, 2020/07
Steam reforming method has been developed for the treatment of organic wastes which are not suitable materials (halogenated oil) for the incineration. This method consists of the gasification process in which organics are vaporized and decomposed with superheated steam and the oxidation process in which vaporized organics are decomposed by oxidizing reaction with heated air. In the gasification process, nonvolatile radionuclides are separated from vaporized waste. Therefore it can be expected that treatment of liquid waste generated from an off-gas treatment system and maintenance operation of the off-gas treatment system become easy to perform. 1,500L of waste oil contaminated with halogen, solvent and uranium was treated using the demonstration scale steam reforming system to examine the performance of the system in 2018. Results obtained this study were as follows; (1) The temperature in the steam reforming system was controlled under the self-regulation temperature. (2) The concentration of CO and NO in the off-gas were controlled less than 100 ppm and 250 ppm respectively. (3) The gasification ratio of waste oil was more than 99%. (4) Concentration of fluorine oil in waste oil is needed to be less than 20wt% to perform stable continuance treatment.
Ishimaru, Tsuneari; Ogata, Nobuhisa; Shimada, Koji; Kokubu, Yoko; Niwa, Masakazu; Asamori, Koichi; Watanabe, Takahiro; Sueoka, Shigeru; Komatsu, Tetsuya; Yokoyama, Tatsunori; et al.
JAEA-Review 2020-010, 46 Pages, 2020/07
This report is a plan of research and development (R&D) on geosphere stability for long-term isolation of high-level radioactive waste (HLW) in Japan Atomic Energy Agency (JAEA), in fiscal year 2020. The objectives and contents in fiscal year 2020 are described in detail based on the JAEA 3rd Medium- and Long-term Plan (fiscal years 2015-2021). In addition, the background of this research is described from the necessity and the significance for site investigation and safety assessment, and the past progress. The plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques.