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Seki, Kotaro; Sasaki, Takayuki*; Akimoto, Yuji*; Tokunaga, Takahito; Tanaka, Kiwamu; Haraga, Tomoko; Ueno, Takashi; Ishimori, Kenichiro; Hoshi, Akiko; Kameo, Yutaka
JAEA-Technology 2016-013, 37 Pages, 2016/07
JAEA-Technology-2016-013.pdf:2.09MB
In this study, based on the simple and rapid analytical method established from the wastes from research facilities, we created analytical schemes which is applicable to rubble and plants collected at Fukushima Daiichi, then transported to Nuclear Science Research Institute of JAEA. We examined the applicability, and confirmed quantifiability of radioactivity concentration with high recovery rate without being affected by fission products such as 
Sr and 
Cs.
Seno, Yasuhiro*; Noguchi, Akira*; Nakayama, Masashi; Sugita, Yutaka; Suto, Shunkichi; Tanai, Kenji; Fujita, Tomoo; Sato, Haruo*
JAEA-Technology 2016-011, 20 Pages, 2016/07
JAEA-Technology-2016-011.pdf:7.56MB
Cementitious materials are expected to be used for the construction of an underground repository for the geological disposal of radioactive wastes. Ordinary Portland Cement(OPC) would conventionally be used in the fields of civil engineering and architecture, however, OPC has the potential to generate a highly alkaline plume (pH
12.5), which will likely degrade the performance of other barriers in the repository such as the bentonite buffer and/or host rock. Low alkaline cementitious materials are therefore being developed that will mitigate the generation of a highly alkaline plume. JAEA has developed a High-volume Fly ash Silica fume Cement (HFSC) as a candidate low alkaline cementitious material. The workability of the HFSC shotcrete was confirmed by conducting In-situ full scale construction tests in the Horonobe underground research laboratory. This report summarizes the results of immersion tests to assess the long-term pH behavior of hardened HFSC cement pastes made with mix designs that are expected to be able to be used in the construction of an underground repository in Japan.
emission reduction goal in 2050Kamiji, Yu; Suzuki, Koichi*; Yan, X.
JAEA-Technology 2016-010, 24 Pages, 2016/07
JAEA-Technology-2016-010.pdf:1.05MB
Japanese government has set the goal of reducing CO emission by 26% in 2030 below the 2013 level, in longer term, by 80% below the 1990 level. To achieve the goals, various measures should be taken. The GTHTR300, a commercial High Temperature Gas-cooled Reactor (HTGR) design being developed by JAEA offers spectrum of heat applications by using its high temperature heat up to 950
C. The potential contribution of CO emission reduction by HTGR is estimated considering domestic and overseas deployment of the GTHTR300. The best estimate for domestic CO reduction is 2.07
10
ton- CO/yr and that from oversea is 2.2510 ton- CO/yr. The sum of these is about 47% of 9.1310 ton- CO/yr which is CO reduction target in 2050, for which deployment of 52 plants in Japan and 113 plants abroad, with each plant containing four 600 MWt reactor units, is required.
Shirai, Nobutoshi; Miura, Yasushi; Tachibana, Ikuya; Omori, Satoru; Wake, Junichi; Fukuda, Kazuhito; Nakano, Takafumi; Nagasato, Yoshihiko
JAEA-Technology 2016-007, 951 Pages, 2016/07
JAEA-Technology-2016-007-01.pdf:11.93MBJAEA-Technology-2016-007-02.pdf:4.7MB
The periodic safety review of TRP is to confirm the safety activities and get effective additional measures the facility safety and its reliability. We implemented 4 items; for (1) evaluation of safety activity implementation, we confirmed we are adequately expanding its safety activities by the necessary documents and schemes. For (2) evaluation of status of safety activities reflecting the latest technical knowledges, we confirmed we reflect latest knowledges for improvement of safety and reliability. For (3) technical evaluation about aging degradation, we can keep the safety of the facilities important to safety and the sea discharge line, under assumption of the present maintenance, because of "focuses for aging degradation". For (4) planning measures about a 10-years-plan that the operator shall implement to keep the facility condition, by the technical evaluation, we found no additional safety plans into maintenance strategies.
Research Team for Fission Product Behavior
JAEA-Review 2016-012, 17 Pages, 2016/07
JAEA-Review-2016-012.pdf:1.46MB
The severe accident (SA) of Fukushima Daiichi Nuclear Power Station (1F) has given rise to enlarged research needs for the improvement of the source term assessment. Fission Product (FP) related researches, however, have not been widely conducted in Japan for many years, thus a framework for such research is not so robust. The Collaborative Laboratories for Advanced Decommissioning Science (CLADS) workshop held in November 2015 was an important opportunity to gain the state of art knowledge on FP and to start discussion between worldwide experts on innovative solution for 1F issues. This report describes the outcomes of FP session conducted in the CLADS workshop. It was pointed out during the workshop that further analyses were needed to properly understand the phenomena that occurred in 1F. The establishment of a Japanese FP platform is here proposed to respond to 1F issues effectively as a means to coordinate the national research efforts and increase communication between worldwide stakeholders. The FPs studies conducted in this frame will provide important information for the decommissioning of 1F, and will be also of great help for the international community to progress the knowledge on FPs behavior. Finally their outcomes could contribute in establishing improved SA management measures.
Hidaka, Akihide; Nakano, Yoshihiro; Watanabe, Yoko; Arai, Nobuyoshi; Sawada, Makoto; Kanaizuka, Seiichi*; Katogi, Aki; Shimada, Mayuka*; Ishikawa, Tomomi*; Ebine, Masako*; et al.
JAEA-Review 2016-011, 208 Pages, 2016/07
JAEA-Review-2016-011-01.pdf:33.85MBJAEA-Review-2016-011-02.pdf:27.68MB
JAEA has been conducting the Instructor Training Program (ITP) since 1996 under the auspices of MEXT to contribute to human resource development in currently 11 Asian countries in the field of radiation utilization for seeking peaceful use of nuclear energy. ITP consists of Instructor Training Course (ITC), Follow-up Training Course (FTC) and Nuclear Technology Seminars. In the ITP, trainings or seminars relating to technology for nuclear utilization are held in Japan by inviting nuclear related people from Asian countries to Japan and after that, the past trainees are supported during FTC by dispatching Japanese specialists to Asian countries. News Letter is also prepared to provide the broad range of information obtained through the trainings for local people near NPPs in Japan. The present report describes the activities of FY2014 ITP and future challenges for improving ITP more effectively.
Hanamuro, Takahiro
JAEA-Review 2016-010, 22 Pages, 2016/07
JAEA-Review-2016-010.pdf:2.98MB
As part of the research and development program on 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, according to the Horonobe URL Project, "Near-field performance study", "Demonstration of repository design option", and "Verification of crustal-movement buffering capacity of sedimentary rocks" are the top priority issues, and schedule for finishing the project and backfill plan will be decides by the end of 2019 Fiscal Year. The Horonobe URL Project is planned to extend over a period of about 20 years. This report summarizes the investigation program for the 2016 fiscal year (2016/2017).
Saito, Hiroshi
JAEA-Review 2016-009, 80 Pages, 2016/07
JAEA-Review-2016-009.pdf:8.28MB
Environmental remediation has been conducted in closed Ningyo-toge Uranium Mine, after decades of mine-related activities. During the remediation, whole procedure, priority, necessary investigations and specific methods have been examined, and issues are clarified which should be solved in the future. For that, it has been recommended that opinions are exchanged among specialists in related fields overseas, and information and their experience are referred. As part of the activities, Ningyo-toge Environmental Engineering Center has been involved continuously in IAEA ENVIRONET, multinational network for environmental remediation. Also, bonds are tightened among participants and IAEA by exchanging opinions and sharing the issues. In parallel, literature survey has been conducted to supplement the information obtained through ENVIRONET and to clarify additionally-required information and targeted sites. The expected information are obtained from the site-visits and now being organized.
Sakai, Toshihiro; Nohara, Tsuyoshi; Ishibashi, Masayuki
JAEA-Research 2016-009, 27 Pages, 2016/07
JAEA-Research-2016-009.pdf:4.05MB
In the Phase II, the geophysical and geological surveys, and the borehole investigation of the research galleries were carried out and the results obtained were used to validate and update the geological model. Through these surveys and analysis work, we confirmed the geological properties and the distribution of model components and evaluated the accuracy of these research methods. This report presents the geological model updated based on the information of the distributions of lithofacies and geological structures at a depth 500m research galleries, and besides, the validity of the geological model of the site scale developed in the Phase I is confirmed by comparing with the updated model.
Takaya, Shigeru; Chikazawa, Yoshitaka; Hayashida, Kiichi; Tagawa, Akihiro; Kubo, Shigenobu; Yamashita, Atsushi
JAEA-Research 2016-006, 66 Pages, 2016/07
JAEA-Research-2016-006.pdf:3.4MB
A maintenance management required to nuclear power reactors at the R&D stage was discussed. It is the most important to ensure safety of nuclear power plants by taking account of characteristics of nuclear power reactors at the R&D stage. In addition, it is needed to establish a system of maintenance management technologies suitable for reactor types. In this report, objectives of maintenance management of nuclear power reactors at the R&D stage was clarified. Next, requirements and consideration for maintenance management was discussed according to the objectives. "Codes for maintenance management of nuclear power plants" and "Guides for maintenance management of nuclear power plants" were refereed in the discussion. Then, a draft of codes for maintenance management of nuclear power plants at the R&D stage were newly proposed. Finally, an example that the draft codes were applied to components containing sodium, typical components of sodium-cooled fast reactor, was presented.
Takeda, Takeshi
JAEA-Data/Code 2016-004, 59 Pages, 2016/07
JAEA-Data-Code-2016-004.pdf:3.34MB
The TR-LF-07 test simulated a loss-of-feedwater transient in a PWR. A SI signal was generated when steam generator (SG) secondary-side collapsed liquid level decreased to 3 m. Primary depressurization was initiated by fully opening a power-operated relief valve (PORV) of pressurizer (PZR) 30 min after the SI signal. High pressure injection (HPI) system was started in loop with PZR 12 s after the SI signal, while it was initiated in loop without PZR when the primary pressure decreased to 10.7 MPa. The primary and SG secondary pressures were kept almost constant because of cycle opening of the PZR PORV and SG relief valves. The PZR liquid level began to drop steeply following the PORV full opening, which caused liquid level formation at the hot leg. The primary pressure became lower than the SG secondary pressure, which resulted in the actuation of accumulator (ACC) system in both loops. The primary feed-and-bleed operation was effective to core cooling because of no core uncovery.
Sakurai, Akitaka; Aoyagi, Kazuhei
JAEA-Data/Code 2016-003, 84 Pages, 2016/07
JAEA-Data-Code-2016-003.pdf:6.42MB
JAEA-Data-Code-2016-003-appendix(DVD-ROM).zip:184.29MB
The Horonobe Underground Research Laboratory (URL) Project has being pursued by Japan Atomic Energy Agency (JAEA) to enhance the reliability of relevant disposal technologies through investigations of the deep geological environment within the host sedimentary formations at Horonobe, northern Hokkaido. The URL project consists of two major research areas, "Geoscientific Research" and "R&D on Geological Disposal Technologies", and proceeds in three overlapping phases, "Phase I: Surface-based investigations", "Phase II: Investigations during tunnel excavation" and "Phase III: Investigations in the underground facilities", over a period of around 20 years. The Phase I geoscientific research was carried out from March 2001 to March 2006 in parallel with design and execution scheme on URL facilities. In addition, identifying key issues that need to be addressed in the Phase II/III investigations was planned. At the beginning of the Phase II investigations, investigation reports related to measurement plan and observational construction program on shaft and drift excavation were published. The observational construction program summarizes the followings from the results of the Phase I investigations: measurements for safety and reasonable constructions, enhancement of shaft design and construction technologies and evaluation of appropriateness for the deep geological environment model estimated before shaft excavation. Currently, Phase III investigation related to geological disposal in underground facilities has been conducting. Also, measurement for consideration of long-term stability of the tunnel has been continued. This report summarizes the measurements data acquired at the West Shaft in 2014 fiscal year for the purpose of the basic data for carrying out the Observational Construction Program.
Yokoi, Shinobu*; Kamishima, Yoshio*; Sadahiro, Daisuke*; Takaya, Shigeru
JAEA-Data/Code 2016-002, 38 Pages, 2016/07
JAEA-Data-Code-2016-002.pdf:1.51MB
Many efforts have been made to implement the System Based Code concept aiming at optimizing margins dispersed in existing codes and standards. Failure probability calculated based on statistical information such as a type of probability distribution, mean (or median) and variance (or standard deviation) for random variables is expected to be a promising quantitative index for margin optimization. Statistical information on material strength, which is also required to calculate the failure probability, has been already reported in JAEA-Data/Code 2015-002 "Structural Properties of Material Strength for Reliability Evaluation of Components of Fast Reactors -Austenitic Stainless Steels-" whereas others have not been identified yet. This report provides methodologies and basic ideas to determine statistical parameters of other random variables, especially variable loads, necessary for reliability evaluation.
Ouchi, Satoshi; Kurumada, Osamu; Kamiishi, Eigo; Sato, Masayuki; Ikekame, Yoshinori; Wada, Shigeru
JAEA-Technology 2016-015, 42 Pages, 2016/06
JAEA-Technology-2016-015.pdf:3.53MB
The purpose of the control rod drive mechanism seating position detector for JRR-3 is one of a method for confirming the shutdown condition of the reactor. The detector has been utilizing more than 25 years with maintenance regularly. However, it is occurred some trouble recently. Moreover, the detector has already been end of manufacture, and even in the successor detector, it unsuitable for the control rod drive mechanism of JRR-3 was confirmed. Therefore, it was necessary to select the adequate detector to the control rod drive mechanism of JRR-3. Accordingly, we built a test device with the aim of verify several detectors for integrity and function. At the time of the test for performance confirmation, it was occurred unexpected problems. Nevertheless, we devise improvement of the problems and took measures. Thus we were able to collect adequate detector for JRR-3 and replace to enhanced detector. This paper reports the Enhanced of Control rod drive mechanism seat position detector.
Sato, Hiroyuki; Nakagawa, Shigeaki; Ohashi, Hirofumi
JAEA-Technology 2016-014, 64 Pages, 2016/06
JAEA-Technology-2016-014.pdf:4.21MB
In this study, we investigate a deterministic approach to select design basis events utilizing information obtained from probabilistic approach. In addition, selections of design basis events are conducted for commercial HTGR designed by JAEA. As a result, an approach for selecting design basis event considering multiple failures of safety systems is established which has not been considered as design basis in the safety guideline for existing nuclear facility. Furthermore, selection of design basis events for commercial HTGR has completed.
Amano, Yuki; Watanabe, Koji; Masaki, Tomoo; Tashiro, Shinsuke; Abe, Hitoshi
JAEA-Technology 2016-012, 21 Pages, 2016/06
JAEA-Technology-2016-012.pdf:1.81MB
To contribute to safety evaluation of fire accident in fuel reprocessing plants, solvent extraction behavior of ruthenium, which could form volatile species, was investigated. Distribution ratios of ruthenium at fire accident conditions were obtained by extraction experiments with several solvent composition at different temperature as parameters. In order to investigate release behavior of ruthenium and europium at fire accident, release ratios of ruthenium and europium were also obtained by solvent combustion experiments.
Fukaya, Yuji; Tokuhara, Kazumi; Nishihara, Tetsuo
JAEA-Research 2016-008, 52 Pages, 2016/06
JAEA-Research-2016-008.pdf:2.18MB
To investigate the xenon stability quantitatively, a study on stability criterion of xenon oscillation based on an analysis solution for HTGR design had been performed. Randall developed the stability criterion method of xenon oscillation based on an analysis solution. And, that have been employed for a LWR design. On the other hand, HTGR is also planted to design new type of reactors, such as Pu fueled reactor, and it is necessary to confirm the xenon stability of those new types of reactors. Then, we developed the criterion method based on the Randall's method termed D-XESC/A, and high xenon stability of HTGR and feasibility for Pu fueled reactor is confirmed by comparing with xenon stability of other types of reactors.
Ozaki, Yusuke; Matsui, Hiroya; Kuwabara, Kazumichi; Tada, Hiroyuki*; Sakurai, Hideyuki*; Kumasaka, Hiroo*; Goke, Mitsuo*; Kobayashi, Shinji*
JAEA-Research 2016-007, 125 Pages, 2016/06
JAEA-Research-2016-007.pdf:34.66MB
In Mizunami Underground Research Laboratory (MIU), the stress analysis of fractured rock have been performed with crack tensor model. In MIU, a reflooding test is performed at 500m stage. In this study, stress analysis of rock during submerging process of the tunnel is performed by using crack tensor model. The deformation of the rock under different water levels in the tunnel is simulated. The stress condition by high pressure due to inflow of groundwater into tunnel is also estimated. These simulation are performed under assumption that groundwater does not permeate into rock for the estimation of maximum pressure acting on the rock. The stress analysis with consideration of permeation of groundwater into rock is also conducted for the estimation of stress condition after the diffusion of water pressure in tunnel. The results of these analyses lead the conclusion that the pressure of the rock reaches the groundwater pressure near the face of tunnel when the tunnel is submerged.