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Journal Articles

Feasibility study on reprocessing of HTGR spent fuel by existing PUREX plant and technology

Fukaya, Yuji; Goto, Minoru; Ohashi, Hirofumi

Annals of Nuclear Energy, 181, p.109534_1 - 109534_10, 2023/02

Feasibility of reprocessing of High Temperature Gas-cooled Reactor (HTGR) spent fuel by existing Plutonium Uranium Redox EXtraction (PUREX) plant and technology has been investigated. The spent fuel dissolved solution includes approximately 3 times amount of uranium-235 and 1.5 times amount of protonium because of the 3 times higher burnup compared with that of Light Water Reactor (LWR). Then, the heavy metal of the spent fuel is planned to be diluted to 3.1 times by depleted uranium to satisfy the limitation of Rokkasho Reprocessing Plant (RRP) plant. In the present study, recoverability of uranium and plutonium with the dilution is confirmed by a simulation with a reprocessing process calculation code. Moreover, the case without the dilution from the economic perspective is investigated. As a result, the feasibility is confirmed without the dilution, and it is expected that the reprocessed amount is reduced to 1/3 compared with a diluted case even though the facility should be optimized from the perspective of mass flow and criticality.

Journal Articles

Study on evaluation method of kernel migration of TRISO fuel for High Temperature Gas-cooled Reactor

Fukaya, Yuji; Okita, Shoichiro; Sasaki, Koei; Ueta, Shohei; Goto, Minoru; Ohashi, Hirofumi; Yan, X.

Nuclear Engineering and Design, 399, p.112033_1 - 112033_9, 2022/12

Kernel migration of TRi-structural ISOtropic (TRISO) fuel for High Temperature Gas-cooled Reactor (HTGR) has been analyzed to investigate the potential dominating effects. Kernel migration is a major fuel failure mode and dominant to determine the lifetime of the fuel for High Temperature engineering Test Reactor (HTTR). However, this study shows that the result and reliability depend on the evaluation method. The evaluation method used in this study takes into account of actual distribution of Coated Fuel Particles (CFPs) and the resulting heterogeneous fuel temperature calculation with such distribution. The result shows that the Kernel Migration Rate (KMR) is predicted to be about 10% less compared with the most conservative evaluation.

JAEA Reports

Assessment report on research and development activities in post-evaluation of third medium-/long-term plan and in pre-evaluation of the fourth medium-/long-term plan on "Research and Development on High Temperature Gas-cooled Reactor and Related Heat Application Technology"

Shinohara, Masanori; Sumita, Junya; Shibata, Taiju; Hirata, Masaru

JAEA-Evaluation 2022-006, 198 Pages, 2022/11

Japan Atomic Energy Agency (JAEA) received a post-evaluation of the third medium-/long-term plan (from FY2015 to FY2021) and pre-evaluation of the fourth medium-/long-term plan (from FY2022 to FY2028) from 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 evaluation subjects of HTGR and related heat application technologies. As a result, for the post-evaluation of the third medium-/ long-term plan, two of the ten technical committee members concluded a score of "S", seven members concluded "A" and one member concluded "B". The comprehensive evaluation concluded a score of "A". On the other hand, one of the two humanities and social sciences members concluded a score of "B", one members concluded "C". The comprehensive evaluation concluded a score of "B". For the pre-evaluation of the fourth medium-/long-term plan, although there were some items that several evaluation committee members rated as "needs improvement," the majority of the committee members judged the plan to be appropriate. This report describes the members of the Evaluation Committee, assessment items, assessment results and JAEA's measures following the assessment.

Journal Articles

Evaluation of power distribution calculation of the very high temperature reactor critical assembly (VHTRC) with Monte Carlo MVP3 code

Simanullang, I. L.*; Nakagawa, Naoki*; Ho, H. Q.; Nagasumi, Satoru; Ishitsuka, Etsuo; Iigaki, Kazuhiko; Fujimoto, Nozomu*

Annals of Nuclear Energy, 177, p.109314_1 - 109314_8, 2022/11

Journal Articles

Present status of JAEA's R&D toward HTGR deployment

Shibata, Taiju; Nishihara, Tetsuo; Kubo, Shinji; Sato, Hiroyuki; Sakaba, Nariaki; Kunitomi, Kazuhiko

Nuclear Engineering and Design, 398, p.111964_1 - 111964_4, 2022/11

 Times Cited Count:0

Japan Atomic Energy Agency (JAEA) has been promoting the research and development (R&D) of High Temperature Gas-cooled Reactor (HTGR). R&D on reactor technologies is carried out by using High Temperature engineering Test Reactor (HTTR). The HTTR was resumed without significant reinforcements in 2021. On January 2022, a safety demonstration test under the OECD/NEA LOFC project was carried out. JAEA is promoting R&D on a carbon-free hydrogen production by thermochemical water splitting Iodine-Sulfur process (IS process). JAEA conducts design study for various HTGR systems toward commercialization. A new test program about demonstration of hydrogen production by the HTTR was launched. Steam methane reforming hydrogen production system was selected for the first demonstration by 2030.

JAEA Reports

Operation, test, research and development of the High Temperature Engineering Test Reactor (HTTR) (FY2020)

Department of HTTR

JAEA-Review 2022-018, 90 Pages, 2022/09

JAEA-Review-2022-018.pdf:2.85MB

The High Temperature Engineering Test Reactor (HTTR) is the first High Temperature Gas-cooled Reactor (HTGR) constructed in Japan at the Oarai Research and Development Institute of the Japan Atomic Energy Agency with 30MW in thermal power and 950$$^{circ}$$C of maximum outlet coolant temperature. The purpose of the HTTR is establishment of basic HTGR technologies, demonstration of HTGR safety characteristics and so on. The HTTR has had a lot of experience of HTGRs' operation and maintenance throughout rated power operations, safety demonstration tests, long-term high temperature operations and demonstration tests relevant to HTGRs' R&Ds. In the fiscal year 2020, we continued to make effort to restart of the HTTR that stopped since the 2011 off the Pacific coast of Tohoku Earthquake. On 3rd June 2020, we obtained permission to the New Regulatory Requirements which make great progress toward the restart of the HTTR. This report summarizes the activities carried out in the fiscal year 2020, which were the situation of the New Regulatory Requirements screening of the HTTR, the operation and maintenance of the HTTR, R&Ds relevant to commercial-scale HTGRs, the international cooperation on HTGRs and so on.

Journal Articles

Calculation of shutdown gamma distribution in the high temperature engineering test reactor

Ho, H. Q.; Ishii, Toshiaki; Nagasumi, Satoru; Ono, Masato; Shimazaki, Yosuke; Ishitsuka, Etsuo; Goto, Minoru; Simanullang, I. L.*; Fujimoto, Nozomu*; Iigaki, Kazuhiko

Nuclear Engineering and Design, 396, p.111913_1 - 111913_9, 2022/09

JAEA Reports

Document collection of the Special Committee on HTTR Heat Application Test

Aoki, Takeshi; Shimizu, Atsushi; Iigaki, Kazuhiko; Okita, Shoichiro; Hasegawa, Takeshi; Mizuta, Naoki; Sato, Hiroyuki; Sakaba, Nariaki

JAEA-Review 2022-016, 193 Pages, 2022/08

JAEA-Review-2022-016.pdf:42.06MB

Aiming to realize a massive, cost-effective and carbon-free hydrogen production technology utilizing a high temperature gas cooled reactor (HTGR), Japan Atomic Energy Agency (JAEA) is planning a HTTR heat application test producing hydrogen with High Temperature Engineering Test Reactor (HTTR) achieved 950$$^{circ}$$C of the highest reactor outlet coolant temperature in the world. In the HTTR heat application test, it is required to establish its safety design realizing highly safe connection of a HTGR and a hydrogen production plant by the Nuclear Regulation Authority to obtain the permission of changes to reactor installation. However, installation of a system connecting the hydrogen production plant and a nuclear reactor, and its safety design has not been conducted so far in conventional nuclear power plant including HTTR in the world. A special committee on the HTTR heat application test, established under the HTGR Research and Development Center, considered a safety design philosophy for the HTTR heat application test based on an authorized safety design of HTTR in terms of conformity to the New Regulatory Requirements taking into account new considerable events as a result of the plant modification and connection of the hydrogen production plant. This report provides materials of the special committee such as technical reports, comments provided from committee members, response from JAEA for the comments and minutes of the committee.

Journal Articles

Study on the effect of long-term high temperature irradiation on TRISO fuel

Shaimerdenov, A.*; Gizatulin, S.*; Dyussambayev, D.*; Askerbekov, S.*; Ueta, Shohei; Aihara, Jun; Shibata, Taiju; Sakaba, Nariaki

Nuclear Engineering and Technology, 54(8), p.2792 - 2800, 2022/08

 Times Cited Count:0 Percentile:0.02(Nuclear Science & Technology)

Journal Articles

Transient thermal-hydraulic analysis for thermal load fluctuation test using HTTR

Aoki, Takeshi; Sato, Hiroyuki

Proceedings of 29th International Conference on Nuclear Engineering (ICONE 29) (Internet), 6 Pages, 2022/08

High temperature gas-cooled reactor (HTGR) has a potential to produce competitive and large amount of carbon-free hydrogen. It is required to establish the control method and system for the HTGR hydrogen production system to maintain its normal operation against the abnormality in the hydrogen production facility through performance evaluations of the control system by transient thermal-hydraulic analysis. In the present study, the reactor response against the disturbance in the reactor inlet coolant temperature was revealed in the HTGR hydrogen production system. The analytical results showed that the reactor outlet coolant control system enabled to control the variation of the reactor outlet coolant temperature was less than 4$$^{circ}$$C against 30$$^{circ}$$C of large disturbance in the reactor inlet coolant temperature and to maintain its normal operation in the HTGR hydrogen production system. Thus, the effectiveness of the control method was confirmed.

JAEA Reports

Calculation of nuclear core parameters for HTTR; Report of summer holiday practical training 2021

Isogawa, Hiroki*; Naoi, Motomasa*; Yamasaki, Seiji*; Ho, H. Q.; Katayama, Kazunari*; Matsuura, Hideaki*; Fujimoto, Nozomu*; Ishitsuka, Etsuo

JAEA-Technology 2022-015, 18 Pages, 2022/07

JAEA-Technology-2022-015.pdf:1.37MB

As a summer holiday practical training 2021, the impact of 10 years long-term shutdown on critical control rod position of the HTTR and the delayed neutron fraction ($$beta$$$$_{rm eff}$$) of the VHTRC-1 core were investigated using Monte-Carlo MVP code. As a result, a long-term shutdown of 10 years caused the critical control rods of the HTTR to withdraw about 4.0$$pm$$0.8 cm compared to 3.9 cm in the experiment. The change in critical control rods position of the HTTR is due to the change of some fission products such as $$^{241}$$Pu, $$^{241}$$Am, $$^{147}$$Pm, $$^{147}$$Sm, $$^{155}$$Gd. Regarding the $$beta$$$$_{rm eff}$$ calculation of the VHTRC-1 core, the $$beta$$$$_{rm eff}$$ value is underestimate of about 10% in comparison with the experiment value.

JAEA Reports

Safety design philosophy of HTTR Heat Application Test Facility

Aoki, Takeshi; Shimizu, Atsushi; Iigaki, Kazuhiko; Okita, Shoichiro; Hasegawa, Takeshi; Mizuta, Naoki; Sato, Hiroyuki; Sakaba, Nariaki

JAEA-Technology 2022-011, 60 Pages, 2022/07

JAEA-Technology-2022-011.pdf:2.08MB

Japan Atomic Energy Agency is planning a High Temperature Engineering Test Reactor (HTTR) heat application test producing hydrogen with the HTTR which achieved the highest reactor outlet coolant temperature of 950$$^{circ}$$C in the world to realize a massive, cost-effective and carbon-free hydrogen production technology utilizing a high temperature gas cooled reactor (HTGR). In the HTTR heat application test, it is required to establish its safety design for coupling a hydrogen production plant to HTGR through the licensing by the Nuclear Regulation Authority (NRA). A draft of a safety design philosophy for the HTTR heat application test facility was considered taking into account postulated events due to the plant modification and coupling of the hydrogen production plant based on the HTTR safety design which was authorized through the safety review of the NRA against New Regulatory Requirements. The safety design philosophy was examined to apply proven conventional chemical plant standards to the hydrogen production plant for ensuring public safety against disasters caused by high pressure gases. This report presents a result of a consideration on safety design philosophies regarding the reasonability and condition to apply the High Pressure Gas Safety Act for the hydrogen production plant, safety classifications, seismic design classification, identification of important safety system.

Journal Articles

Reactor physics experiment in a graphite moderation system for HTGR, 3

Fukaya, Yuji; Okita, Shoichiro; Kanda, Shun*; Goto, Masaki*; Nakajima, Kunihiro*; Sakon, Atsushi*; Sano, Tadafumi*; Hashimoto, Kengo*; Takahashi, Yoshiyuki*; Unesaki, Hironobu*

KURNS Progress Report 2021, P. 101, 2022/07

The Japan Atomic Energy Agency (JAEA) started the Research and Development (R&D) to improve nuclear prediction techniques for High Temperature Gas-cooled Reactors (HTGRs) in 2018. The objectives are to intro-duce the generalized bias factor method to avoid full mock-up experiment for the first commercial HTGR and to improve neutron instrumentation system by virtue of the particular characteristics due to a graphite moderation system. For this end, we composed B7/4"G2/8"p8EU(3)+3/8"p38EU in the B-rack of Kyoto University Critical Assembly (KUCA) in 2021.

Journal Articles

Development of proton exchange membranes for HI concentration in thermochemical water-splitting IS process

Tanaka, Nobuyuki

Maku, 47(4), p.197 - 201, 2022/07

A thermochemical water-splitting iodine-sulfur process enables us to provide the Carbon-free hydrogen (H$$_{2}$$) at high-efficiency levels, and it uses high-temperature heat sources, including high-temperature gas-cooled reactors, solar heat, and more. The cation exchange membranes (CEMs) for the HI mediated electro electrodialysis (EED) were developed using a radiation grafted polymerization method in order to improve the process efficiency of the IS process. High proton (H$$^{+}$$) conductivity and selectivity are required for the performance of CEMs to reduce the consumption energy for EED. The H$$^{+}$$ conductivity of the radiation grafted CEMs were successfully improved by controlling the grafting amount, comparing with that of Nafion. Moreover, the H$$^{+}$$ selectivity and water transport of the developed CEMs was improved by introducing the crosslinker. Currently, the further improvement of the membrane performance is underway by using the ion-track grafting technic.

JAEA Reports

Assessment report on research and development activities in FY2020 activity and in prospective evaluation of third mid-to long-term plan "Research and development on high temperature gas-cooled reactor and related heat application technology"

Shinohara, Masanori; Sumita, Junya; Shibata, Taiju; Hirata, Masaru

JAEA-Evaluation 2022-001, 104 Pages, 2022/06

JAEA-Evaluation-2022-001.pdf:28.15MB

Japan Atomic Energy Agency received the annual evaluation of FY2020, the research plan of FY2021 and the prospective evaluation of the third mid- to long-term plan (from FY2015 to FY2021) from 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 evaluation subjects of HTGR and related heat application technology. As a result, for the annual evaluation of FY2020, one of the ten technical committee members concluded a score of "S", eight members concluded "A" and one member concluded "B". The comprehensive evaluation was concluded a score of "A". On the other hand, two humanities and social sciences committee members concluded "B". For the prospective evaluation of the third mid- to long-term plan, one of the ten technical committee members concluded a score of "S", eight members concluded "A" and one member concluded "B". The comprehensive evaluation was concluded a score of "A". On the other hand, two humanities and social sciences committee members concluded "B". This report describes the members of the Evaluation Committee, assessment items, assessment results and JAEA's measures following the assessment.

JAEA Reports

FORNAX-A1.0 for calculation of fission product release amount from fuel rods of pin-in-block-type high temperature gas-cooled reactors

Aihara, Jun

JAEA-Data/Code 2022-003, 77 Pages, 2022/06

JAEA-Data-Code-2022-003.pdf:1.62MB

FORNAX-A1.0 is a calculation code for amount of fission product (FP) released from fuel rods of pin-in-type high temperature gas-cooled reactors (HTGRs). FORNAX-A1.0 is based on Fick's laws of diffusion and can calculate FP release amount from fuel rod under normal operation and accidents without failure (including oxidation) of graphite sleeves and fuel compacts and without melting of fuel kernel, for example, stopping fission and increase in temperature and/or failure fraction of coated fuel particles. This report is for explanation of outline, basic formulae and numerical analysis method of FORNAX-A1.0 code.

Journal Articles

Re-evaluation of electricity generation cost of HTGR

Fukaya, Yuji; Ohashi, Hirofumi; Sato, Hiroyuki; Goto, Minoru; Kunitomi, Kazuhiko

Nihon Genshiryoku Gakkai Wabun Rombunshi, 21(2), p.116 - 126, 2022/06

An improvement electricity generation cost evaluation method for High Temperature Gas-cooled Reactors (HTGRs) has been performed. Japan Atomic Energy Agency (JAEA) had completed the commercial HTGR concept named Gas Turbine High Temperature Reactor (GTHTR300) and the electricity generation cost evaluation method approximately a decade ago. The cost evaluation was developed based on the method of Federation of Electric Power Companies (FEPC). The FEPC method was drastically revised after the Fukushima Daiichi nuclear disaster. Moreover, the escalation of material and labor cost for the decade should be consider to evaluate the latest cost. Therefore, we revised the cost evaluation method for GTHTR300 and the cost was compared with that of Light Water Reactor (LWR). As a result, it was found that the electricity generation cost of HTGR of 7.9 yen/kWh is cheaper than that of LWR of 11.7 yen/kWh by approximately 30% at the capacity factor of 70%.

Journal Articles

Preliminary experiment in a graphite-moderated core to avoid full mock-up experiment for the future first commercial HTGR

Okita, Shoichiro; Fukaya, Yuji; Sakon, Atsushi*; Sano, Tadafumi*; Takahashi, Yoshiyuki*; Unesaki, Hironobu*

Proceedings of International Conference on Physics of Reactors 2022 (PHYSOR 2022) (Internet), 9 Pages, 2022/05

Journal Articles

Computed tomography neutron detector system to observe power distribution in a core with long neutron flight path

Fukaya, Yuji; Okita, Shoichiro; Nakagawa, Shigeaki; Goto, Minoru; Ohashi, Hirofumi

Annals of Nuclear Energy, 168, p.108911_1 - 108911_7, 2022/04

 Times Cited Count:0 Percentile:0.02(Nuclear Science & Technology)

A power distribution monitoring system by using a moving detector for a core with a long neutron flight path has been proposed. High Temperature Gas-cooled Reactor (HTGR) and Fast Reactor (FR) has a long neutron flight path and the neutrons reach to detector far from fuel assembly in the center of the core unlike Light Water Reactor (LWR). By using the feature, power distribution can be observed with a few detectors by moving the detector and computed tomography technology similar to X-ray Computed Tomography (CT). For a small-sized core, the power distribution can be evaluated only by an ex-core neutron detector. For a large-sized core with inner detectors, the power distribution can be observed with a small number of in-core detectors even if the deployment is limited due to material integrity conditions such as temperature environment. The feasibility is numerically confirmed by simulations of the HTGR core and its detector response. It is expected to observe the power distribution in the core of HTGR and FR, which is difficult continuously to deploy in-core detectors because of high temperature and/or high irradiation damage.

Journal Articles

Spark plasma sintering of SiC/graphite functionally graded materials

Watanabe, Masashi; Yokoyama, Keisuke; Imai, Yoshiyuki; Ueta, Shohei; Yan, X.

Ceramics International, 48(6), p.8706 - 8708, 2022/03

 Times Cited Count:2 Percentile:88.97(Materials Science, Ceramics)

Previous studies have used various methods for sintering of SiC, carbon, and SiC/carbon functionally graded materials (FGM). However, no experimental studies on SiC/graphite FGM manufacturing using the spark plasma sintering (SPS) method have been reported. In this study, a SiC/graphite FGM specimen has been fabricated using SPS. The interface between the adjacent layers of the sintered specimen exhibits no apparent defects such as gaps or delaminations. The SiC and graphite phases in the specimen show no substantial change before and after sintering.

1831 (Records 1-20 displayed on this page)