Sakai, Kenji; Obayashi, Hironari; Saito, Shigeru; Sasa, Toshinobu; Sugawara, Takanori; Watanabe, Akihiko*
JAEA-Technology 2019-009, 18 Pages, 2019/07
Construction of Transmutation Experimental Facility (TEF) is under planning in the Japan Proton Accelerator Research Complex (J-PARC) program to promote R&D on the transmutation technology with using accelerator driven systems (ADS). ADS Target Test Facility (TEF-T) in TEF will develop spallation target technology and study on target materials with irradiating high intensity proton beams on a lead-bismuth eutectic (LBE) target. For safe and efficient beam operation, a general control system (GCS) will be constructed in TEF-T. GCS comprises several subsystems, such as a network system (LAN), an integral control system (ICS), an interlock system (ILS), and a timing distribution system (TDS) according to their roles. Especially, the ICS plays the important role that executes integral operations in the entire facility, acquires, stores and distributes operation data. We planned to develop a prototype of the ICS, to evaluate its concrete performances such as data transmission speeds, data storage capability, control functions, long-term stability of the system, and to utilize them for design of the actual ICS. This report mentions to product the prototype of ICS and to apply it to remote operations of instruments for developing LBE target technology.
Ishitsuka, Etsuo; Matsunaka, Ichiro*; Ishida, Hiroki*; Ho, H. Q.; Ishii, Toshiaki; Hamamoto, Shimpei; Takamatsu, Kuniyoshi; Kenzhina, I.*; Chikhray, Y.*; Kondo, Atsushi*; et al.
JAEA-Technology 2019-008, 12 Pages, 2019/07
As a summer holiday practical training 2018, the feasibility study for nuclear design of a nuclear battery using HTTR core was carried out. As a result, it is become clear that the continuous operations for about 30 years at 2 MW, about 25 years at 3 MW, about 18 years at 4 MW, about 15 years at 5 MW are possible. As an image of thermal design, the image of the nuclear battery consisting a cooling system with natural convection and a power generation system with no moving equipment is proposed. Further feasibility study to confirm the feasibility of nuclear battery will be carried out in training of next fiscal year.
JAEA-Review 2019-008, 20 Pages, 2019/07
As part of the research and development program on the geological disposal of high-level radioactive waste (HLW), the Horonobe Underground Research Center, a division of the Japan Atomic Energy Agency (JAEA), is implementing the Horonobe Underground Research Laboratory Project (Horonobe URL Project) with the aim at investigating sedimentary rock formations. According to the research plan described in the 3rd Mid- and Long- term Plan of JAEA, "Near-field performance study", "Demonstration of repository design option", and "Verification of crustal-movement buffering capacity of sedimentary rocks" are the top priority issues of the Horonobe URL Project, and schedule of future research and backfill plans of the project will be decided by the end of 2019 Fiscal Year. The Horonobe URL Project is planned to extend over a period of about 20 years. The investigations will be conducted in three phases, namely "Phase 1: Surface-based investigations", "Phase 2: Construction phase" (investigations during construction of the underground facilities) and "Phase 3: Operation phase" (research in the underground facilities). This report summarizes the investigation program for the 2019 fiscal year (2019/2020). In the 2019 fiscal year, investigations in "geoscientific research", including "development of techniques for investigating the geological environment", "development of engineering techniques for use in the deep underground environment" and "studies on the long-term stability of the geological environment", are continuously carried out. Investigations in "research and development on geological disposal technology", including "improving the reliability of disposal technologies" and "enhancement of safety assessment methodologies", are also continuously carried out.
Department of HTTR
JAEA-Review 2019-006, 97 Pages, 2019/07
The High Temperature Engineering Test Reactor (HTTR) was constructed to establish and upgrade basic technologies for HTGRs. In the fiscal year 2017 we continued activities for re-operation of the HTTR and have been inspected the application document for the HTTR licensing to prove conformity with the new regulatory requirements for research reactors taken effect since December 2013 had been applied. This report summarizes activities and results of HTTR operation, maintenance, international cooperation and so on which were carried out in the fiscal year 2017.
Kwon, Saerom*; Konno, Chikara; Ota, Masayuki*; Ochiai, Kentaro*; Sato, Satoshi*; Kasugai, Atsushi*
Fusion Engineering and Design, 144, p.209 - 214, 2019/07
We performed a TENDL-2017 benchmark test with iron shielding experiments by using 40 and 65 MeV neutrons, in order to verify a nuclear data library above 20 MeV for neutronics analyses of A-FNS. We found out that the calculated neutron spectra with TENDL-2017 unnaturally increased near 30 MeV. We figured out that incorrect secondary neutron spectrum data in Fe, Fe and Fe at 30 MeV caused the increase of the neutron flux. Similar problems occurred in a lot of nuclei of TENDL-2017, TENDL-2015 and FENDL-3.1d from TENDL-2010 and TENDL-2011.
Yamanouchi, Michihiko*; Oyamada, Tatsuro*; Sato, Koichi*; Ota, Hiromichi*; Ieda, Junichi
IEEE Transactions on Magnetics, 55(7), p.1400604_1 - 1400604_4, 2019/07
Narita, Hirokazu*; Nicolson, R. M.*; Motokawa, Ryuhei; Ito, Fumiyuki*; Morisaku, Kazuko*; Goto, Midori*; Tanaka, Mikiya*; Heller, W. T.*; Shiwaku, Hideaki; Yaita, Tsuyoshi; et al.
Inorganic Chemistry, 58(13), p.8720 - 8734, 2019/07
Sueoka, Shigeru; Tagami, Takahiro*
Island Arc, 28(4), p.e12305_1 - e12305_8, 2019/07
no abstracts in English
Narukawa, Takafumi; Amaya, Masaki
Journal of Nuclear Science and Technology, 56(7), p.650 - 660, 2019/07
Oi, Motoki; Teshigawara, Makoto; Harada, Masahide; Ikeda, Yujiro
Journal of Nuclear Science and Technology, 56(7), p.573 - 579, 2019/07
In pulsed neutron sources, a neutron absorber called decoupler is attached to the moderator to sharpen the neutron pulses for achieving good neutron energy resolutions. Cadmium and boron carbide (BC) are widely used as the decoupler materials. However, it is difficult to use BC in MW-class spallation neutron sources owing to high burn-up, which decreases cut-off energy and increase of helium gas swelling. To solve these issues, we introduce the concept of pre-decoupler to reduce neutron absorption in the BC decoupler, which is sandwiched by appropriate neutron absorption materials. Then, we study impacts of the pre-decouplers on BC decoupler in terms of burn-up by performing simplified model calculations. It is shown that neutron absorption in BC is reduced by 60% by using a Cd pre-decoupler without neutron intensity penalty. Moreover, helium gas swelling in BC is restrained to be one-third of the value when not using the pre-decoupler.
Tsuchiya, Harufumi; Koizumi, Mitsuo; Kitatani, Fumito; Harada, Hideo
Nuclear Instruments and Methods in Physics Research A, 932, p.16 - 26, 2019/07
Nuclear Science and Engineering, 193, p.776 - 789, 2019/07
It is known that the convergence of standardized time series (STS) to Brownian bridge yields standard deviation estimators of the sample mean of correlated Monte Carlo tallies. In this work, a difference scheme based on a stochastic differential equation is applied to STS in order to obtain a new functional statistic (NFS) that converges to Brownian motion (BM). As a result, statistical error estimation improves twofold. First, the application of orthonormal weighting to NFS yields a new set of asymptotically unbiased standard deviation estimators of sample mean. It is not necessary to store tallies once the updating of estimator computation is finished at each generation. Second, it becomes possible to assess the convergence of sample mean in an assumption-free manner by way of the comparison of power spectra of NFS and BM. The methodology is demonstrated for three different types of problems encountered in Monte Carlo criticaliti calculation.
Matsuya, Yusuke; McMahon, S. J.*; Ghita, M.*; Yoshii, Yuji*; Sato, Tatsuhiko; Date, Hiroyuki*; Prise, K. M.*
Scientific Reports (Internet), 9(1), p.9483_1 - 9483_12, 2019/07
In radiotherapy, intensity modulated radiation fields and complex dose-delivery are used to prescribe doses to tumors. Here, we analyzed the impact of modulated field on radio-sensitivity and cell recovery during irradiation time. The dose was delivered to either 50% of the area of the flask containing cells (half-field) or 100% of the flask (uniform-field). We also modelled cell-killing considering dose-rate effects and intercellular signals. It is found that (i) in-field cell survival under half-field exposure is higher than uniform-field exposure even with the same dose; (ii) the importance of sub-lethal damage repair in normal human skin fibroblast cells under the half-field is reduced; (iii) the increase of cell survival under half-field is predominantly attributed to not rescue effects (increased repair) but protective effects (reduced initial DNA lesion yield). These findings provide new understanding of radio-sensitivity for hit and non-hit cells under non-uniform exposure.
Yashiro, Shigeo; Shoji, Makoto; Ueno, Tokio; Ueno, Asuka
JAEA-Testing 2019-001, 28 Pages, 2019/06
Center for Computational Science & e-Systems of Japan Atomic Energy Agency, provides an environment for using PCs with thin client systems to our organization's officers, operation management organization, common business organization, base management department, and offices for each research and development department. Supports the efficient and smooth implementation of our decision-making, core operations and related tasks. This report is the characteristics and construction policy (basic requirements) of the thin client system and hardware newly obtained in the subsequent operation, which were arranged and examined on the introduction of the existing thin client system updated in October 2017. It is a summary of the results, findings, etc. of the occupied thin client system.
Imamura, Hiroaki; Suzuki, Masashi*; Shimoyama, Kazuhito; Miyakoshi, Hiroyuki
JAEA-Technology 2019-005, 163 Pages, 2019/06
For the R&D of safety enhance in future fast reactor development, the constracted the large sodium test loop (mother loop) in advanced technology experiment sodium facility (AtheNa) was completed. The sodium test loop possesses the largest capacity of about 240 tons of the world's largest sodium and can supply impurity-controlled high temperature sodium to large structural and technology demonstration test sections. It is greatly expected as R&D such as future international cooperation. For the purpose of future R&D tests, this report compiled the design specifications, fabrication and performance confirmation results of sodium test loop.
Murakami, Masashi; Hoshino, Yuzuru; Nakatani, Takayoshi; Sugaya, Toshikatsu; Fukumura, Nobuo*; Sanda, Toshio*; Sakai, Akihiro
JAEA-Technology 2019-003, 50 Pages, 2019/06
Toward the establishment of a common approach to determine the radioactivity concentrations in dismantling wastes arising from research reactors, radionuclide concentrations in the reactor structure materials of aluminum, carbon steel, shield concrete, and graphite of TRIGA Mark II reactor at Rikkyo University, Japan, were evaluated with both radiochemical analysis and theoretical calculation. The measured nuclides by the radiochemical analysis were H, Co, and Ni in aluminum, H, Co, Ni, and Eu in carbon steel, H, Co, and Eu in shield concrete, and H, C, Co, Ni, and Eu in graphite. Neutron-flux distributions and neutron-induced activities were computed with DORT and ORIGEN-ARP codes, respectively. Using the results of material composition analysis, radioactivity concentrations were conservatively predicted with good accuracy except for graphite material.
Otani, Kyohei; Sato, Tomonori; Kaji, Yoshiyuki; Yamamoto, Masahiro
JAEA-Review 2019-007, 15 Pages, 2019/06
Metallic pipes under solid-liquid two phase flow is damaged by collision of solid particle to the pipe walls, and this phenomenon is named "erosion". In the case of the liquid is corrosive solution, further damage is occurred on the pipe walls chemically, and this named "erosion-corrosion". In the Fukushima Daiichi decommissioning project, the fuel debris will be crushed during removal operation of the debris and micro debris particles would be generated. It is estimated that the pipes of the circulating cooling system would be damaged under the solid-liquid two phase flow containing fuel debris particles. For the reason, the previous study about erosion and erosion-corrosion of metallic materials under solid-liquid two phase flow was surveyed. The survey showed that the damage rate by erosion and erosion-corrosion is influence by a lot of parameter in comparison to the corrosion rate which occurred in no-flow solution. Therefore, it is necessary to pay attention to selecting the experimental method and condition before the investigation about erosion-corrosion of metallic materials under solid-liquid two phase flow is carried out.
Takeuchi, Ryuji; Iwatsuki, Teruki; Matsui, Hiroya; Nohara, Tsuyoshi; Onoe, Hironori; Ikeda, Koki; Mikake, Shinichiro; Hama, Katsuhiro; Iyatomi, Yosuke; Sasao, Eiji
JAEA-Review 2019-005, 76 Pages, 2019/06
The Mizunami Underground Research Laboratory (MIU) project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of geological disposal technologies through investigations of the deep geological environment in the crystalline rock (granite) at Mizunami City, Gifu Prefecture, central Japan. On the occasion of the research program and management system revision of the entire JAEA organization in 2014, JAEA identified three remaining important issues on the geoscientific research program based on the latest results of the synthesizing research and development: "Development of countermeasure technologies for reducing groundwater inflow", "Development of modeling technologies for mass transport" and "Development of drift backfilling technologies". The research and development on three remaining important issues have been carrying out on the MIU project. In this report, the current status of the research and development activities and construction in fiscal year 2017 is summarized.
Materials Sciences Research Center
JAEA-Evaluation 2019-005, 121 Pages, 2019/06
Japan Atomic Energy Agency (JAEA) consulted an assessment committee, "Evaluation Committee of Research Activities for Research and Development in Science and Technology using Neutron and Synchrotron Radiation" (Committee) for interim assessment of "Research and Development in Science and Technology using Neutron and Synchrotron Radiation", in accordance with "General Guideline for the Evaluation of Government Research and Development (R&D) Activities" by Cabinet Office, Government of Japan, "Guideline for Evaluation of R&D in Ministry of Education, Culture, Sports, Science and Technology" and "Regulation on Conduct for Evaluation of R&D Activities" by JAEA. In response to the JAEA's request, the Committee assessed the research program and activities on Research and Development in Science and Technology using Neutron and Synchrotron Radiation in Materials Sciences Research Center (MSRC) and Neutron Science Section (NSS) in Materials and Life Science Division (MLSD) of J-PARC Center during the period from April 2015 to December 2018. The Committee evaluated the management, research and development activities based on the explanatory documents prepared by MSRC and NSS and oral presentations with questions-and-answers by the Director General and the Division Heads of the MSRC and the Section Leader of the NSS. This report summarizes the results of the assessment by the Committee with the Committee report attached.
Sector of Fast Reactor and Advanced Reactor Research and Development
JAEA-Evaluation 2019-004, 47 Pages, 2019/06
Japan Atomic Energy Agency (hereafter referred to as "JAEA") consulted with the "Evaluation Committee of Research and Development Activities for Fast Reactor Cycle" (hereinafter referred to as "Committee"), which consists of specialists in the fields of the evaluation subjects of fast reactor cycle technologies, for interim assessment of R&D activities of fast reactor cycle in the 3rd Mid- and Long-Term Plan (from April 2015 to March 2022) in accordance with "General Guideline for the Evaluation of Government Research and Development (R&D) Activities" by Cabinet Office, Government of Japan, "Guideline for Evaluation of R&D in Ministry of Education, Culture, Sports, Science and Technology" and Regulation on Conduct for Evaluation of R&D Activities" by JAEA. In response to the JAEA's request, the Committee assessed the R&D program of fast reactor cycle technologies during the period of four years from April 2015 to March 2018. The Committee evaluated the management and R&D activities based on the explanatory documents and oral presentations by JAEA. The results of the evaluation were compiled in assessment report that was organized including the reasons for evaluation and the opinions and recommendations. This report is issued for the purpose of actively disseminate evaluation information to the people of Japan (based on General Guideline), which lists the members of the Committee and outlines the assessment items and the review process for procedure of the assessment. The assessment report which was issued by the Committee is attached.