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Journal Articles

Development and validation of analysis code for spallation products behavior in LBE coolant system of ADS comparing with the distribution data in MEGAPIE spallation target

Miyahara, Shinya*; Arita, Yuji*; Nakano, Keita; Maekawa, Fujio; Sasa, Toshinobu; Obayashi, Hironari; Takei, Hayanori

Nuclear Engineering and Design, 403, p.112147_1 - 112147_17, 2023/03

It is important to evaluate the inventories and the release and transport behavior of the spallation products (SPs) in the Lead-Bismuth Eutectic (LBE) coolant system of Accelerator Driven System (ADS) for the safety studies of the radiological hazard both in the cases of normal operation and accident. University of Fukui and JAEA have been developing the computer analysis code TRAIL (Transport of RAdionuclides In Liquid metal systems) which predicts the time dependent behavior of SPs within the LBE coolant system of ADS for the wide range of operational events. The source term of both radioactive and stable SPs in the LBE coolant is given as input and the radioactive decay chain model for the radioactive SPs is implemented in the code to evaluate the effect of precursors on the SPs mobility. This paper presents the recent advancement status of the code development and the validation results comparing with the distribution data of volatile SPs in MEGAPIE spallation target.

Journal Articles

Numerical reproduction of the seasonal variation in dissolved uranium in Lake Biwa

Saito, Tatsuo; Yamazawa, Hiromi*; Mochizuki, Akihito

Journal of Environmental Radioactivity, 255, p.107035_1 - 107035_14, 2022/12

 Times Cited Count:0 Percentile:0(Environmental Sciences)

The seasonal variation of dissolved U (DU) in Lake Biwa was reproduced by the following model and parameter research. The introduced models are the water-DU mass balance, and the ion exchange between UO$$_{2}$$$$^{2+}$$ and H$$^{+}$$ on the lakeshore soil. The optimized parameters were the CEC of the lakeshore, TU as the sum of DU and AU (soil adsorbed U), kads and kdes as the first order reaction rate coefficients during rapid soil adsorption and desorption of U, respectively. Tabulated by the chemical equilibria constituting DU and analyzed the contribution of each chemical species, it is shown that the seasonal variation of DU is caused by the seasonal variation of pH. A correction to the ion-exchange equilibrium to shift to first order rate reaction only when the daily AU ratio increased above kads or decreased below kdes, improved the reproducibility of DU measurements and reproduced the delay of the DU peak from the pH peak.

Journal Articles

A Plan of Proton Irradiation Facility at J-PARC and possibilities of application to nuclear data research

Maekawa, Fujio

JAEA-Conf 2022-001, p.7 - 13, 2022/11

The partitioning and transmutation (P-T) technology has promising potential for volume reduction and mitigation of degree of harmfulness of high-level radioactive waste. JAEA is developing the P-T technology combined with accelerator driven systems (ADS). One of critical issues affecting the feasibility of ADS is the proton beam window (PBW) which functions as a boundary between the accelerator and the sub-critical reactor core. The PBW is damaged by a high-intensity proton beam and spallation neutrons produced in the target, and also by flowing high-temperature liquid lead bismuth eutectic alloy which is corrosive to steel materials. To study the materials damage under the ADS environment, J-PARC is proposing a plan of proton irradiation facility which equips with a liquid lead-bismuth spallation target bombarded by a 400 MeV - 250 kW proton beam. The facility is also open for versatile purposes such as soft error testing of semi-conductor devises, RI production, materials irradiation for fission and fusion reactors, and so on. Application to nuclear data research with using the proton beam and spallation neutrons is also one of such versatile purposes, and we welcome unique ideas from the nuclear data community.

Journal Articles

Beam physics design of a 30-MW beam transport to the target for an accelerator-driven subcritical system

Yee-Rendon, B.; Meigo, Shinichiro; Kondo, Yasuhiro; Tamura, Jun; Nakano, Keita; Maekawa, Fujio; Iwamoto, Hiroki; Sugawara, Takanori; Nishihara, Kenji

Journal of Instrumentation (Internet), 17(10), p.P10005_1 - P10005_21, 2022/10

 Times Cited Count:0 Percentile:0(Instruments & Instrumentation)

To reduce the hazard of minor actinides in nuclear waste, JAEA proposed an accelerator-driven subcritical system (JAEA-ADS). The JAEA-ADS drives a subcritical reactor 800-MWth by 30-MW proton linac delivering the beam to the spallation neutron target inside the reactor. The beam transport to the target (BTT) is required for high-beam power stability and low peak density to ensure the integrity of the beam window. Additionally, the design should have compatible with the reactor design for the maintenance and replacement of the fuel and the beam window. A robust-compact BTT design was developed through massive multiparticle simulations. The beam optics was optimized to guarantee beam window feasibility requirements by providing a low peak density of less than 0.3 $$mu$$A/mm$$^2$$. Beam stability was evaluated and improved by simultaneously applying the linac's input beam and element errors. The input beam errors to the reactor were based on the beam degradation obtained by implementing fast fault compensation in the linac. Those results show that the BTT fulfills the requirements for JAEA-ADS.

Journal Articles

Overview of ADS projects in the world

Yee-Rendon, B.

Proceedings of 31st International Linear Accelerator Conference (LINAC 2022) (Internet), p.310 - 313, 2022/10

Accelerator-driven subcritical systems (ADS) offer an advantageous option for the transmutation of nuclear waste. ADS employs high-intensity proton linear accelerators (linacs) to produce spallation neutrons for a subcritical reactor. Besides the challenges of any megawatt proton machine, ADS accelerator must operate with stringent reliability to avoid thermal stress in the reactor structures. Thus, ADS linacs have adopted a reliability-oriented design to satisfy the operation requirements. This work provides a review and the present status of the ADS linacs in the world.

Journal Articles

Measurement of nuclide production cross sections for proton-induced reactions on $$^{rm nat}$$Ni and $$^{rm nat}$$Zr at 0.4, 1.3, 2.2, and 3.0 GeV

Takeshita, Hayato*; Meigo, Shinichiro; Matsuda, Hiroki*; Iwamoto, Hiroki; Nakano, Keita; Watanabe, Yukinobu*; Maekawa, Fujio

Nuclear Instruments and Methods in Physics Research B, 527, p.17 - 27, 2022/09

 Times Cited Count:0 Percentile:0.02(Instruments & Instrumentation)

To improve accuracy of nuclear design of accelerator driven nuclear transmutation systems and so on, nuclide production cross sections on Ni and Zr were measured for GeV energy protons. The measured results were compared with PHITS calculations, JENDL/HE-2007 and so on.

Journal Articles

On the adsorption and reactivity of element 114, flerovium

Yakushev, A.*; Lens, L.*; D$"u$llmann, Ch. E.*; Khuyagbaatar, J.*; J$"a$ger, E.*; Krier, J.*; Runke, J.*; Albers, H. M.*; Asai, Masato; Block, M.*; et al.

Frontiers in Chemistry (Internet), 10, p.976635_1 - 976635_11, 2022/08

 Times Cited Count:1 Percentile:0(Chemistry, Multidisciplinary)

Flerovium (Fl, element 114) is the heaviest element chemically studied so far. The first chemical experiment on Fl suggested that Fl is a noble-gas-like element, while the second studies suggested that Fl has a volatile-metal-like character. To obtain more reliable conclusion, we performed further experimental studies on Fl adsorption behavior on Si oxide and gold surfaces. The present results suggest that Fl is highly volatile and less reactive than the volatile metal, Hg, but has higher reactivity than the noble gas, Rn.

Journal Articles

Beam dynamics studies for fast beam trip recovery of the Japan Atomic Energy Agency accelerator-driven subcritical system

Yee-Rendon, B.; Kondo, Yasuhiro; Tamura, Jun; Nakano, Keita; Maekawa, Fujio; Meigo, Shinichiro

Physical Review Accelerators and Beams (Internet), 25(8), p.080101_1 - 080101_17, 2022/08

 Times Cited Count:1 Percentile:71.19(Physics, Nuclear)

High reliability and availability are primary goals for the operation of particle accelerators, especially for accelerator-driven subcritical systems (ADS). ADSs employ high-power beams for the transmutation of minor actinide; as a result, the amount and the radiotoxicity of the nuclear waste are considerably reduced. To this end, the Japan Atomic Energy Agency is designing a 30-MW continuous wave (cw) super-conducting proton linear accelerator (linac) that supplies neutrons to an 800-MW subcritical reactor by a spallation process. The major challenge for an ADS linac is the strict control of the beam trip duration and its frequency to avoid thermal stress in the subcritical reactor structures. The maximum allowed beam trips for failures longer than a few seconds are estimated to be far below the rate achieved in current accelerators. Thus, we implemented a combination of hot standby and local compensation that enables a fast beam recovery. This work comprehensively investigated the tolerance of our linac lattice for the local compensations for failures in superconducting cavities and magnets. This scheme includes simultaneous compensation of multiple cavities in independent and same cryomodules that significantly enhance the reliability of the linac. The returned schemes present acceptable beam performance to guarantee the integrity of the linac and the beam transport to the target; moreover, they satisfy the beam stability in the beam window. In addition, the readjusted elements are subjected to moderate stress to ensure a sustainable operation. This manuscript reports the beam dynamics results toward fulfilling the high reliability demanded by an ADS linac.

Journal Articles

Status of the JAEA-ADS superconducting linac design

Yee-Rendon, B.; Kondo, Yasuhiro; Tamura, Jun; Meigo, Shinichiro; Maekawa, Fujio

Proceedings of 64th ICFA Advanced Beam Dynamics Workshop on High Intensity and High Brightness Hadron Beams (ICFA-HB2021) (Internet), p.30 - 34, 2022/04

The Japan Atomic Energy Agency (JAEA) is working in the research and development of an Accelerator Driven Subcritical System (ADS) for the transmutation of nuclear waste. To this end, JAEA is designing a 30-MW CW proton linear accelerator (linac) with a beam current of 20 mA. The JAEA-ADS linac starts with a Normal Conducting (NC) up to an energy of 2.5 MeV. Then, five Superconducting (SC) sections accelerate the beam up to 1.5 GeV. The biggest challenge for this ADS linac is the stringent reliability required to avoid thermal stress in the subcritical reactor, which is higher than the achieved in present accelerators. For this purpose, the linac pursues a strong-stable design that ensures the operation with low beam loss and fault-tolerance capabilities to continue operating in case of failure. This work presents the beam dynamics results toward achieving high reliability for the JAEA-ADS linac.

JAEA Reports

Development of mock-up test loop (IMMORTAL) for LBE spallation target

Obayashi, Hironari; Yamaki, Kenichi*; Yoshimoto, Hidemitsu*; Kita, Satoshi*; Wan, T.*; Sasa, Toshinobu

JAEA-Technology 2021-035, 66 Pages, 2022/03

JAEA-Technology-2021-035.pdf:4.26MB

Construction of Transmutation Experimental Facility (TEF) is under planning in Japan Proton Accelerator Research Complex (J-PARC) program to promote R&Ds on realization of transmutation technology by an accelerator driven system (ADS). As a facility of TEF, ADS Target Test Facility (TEF-T) will provide a spallation target to study target technology and perform post irradiation examination (PIE) of candidate materials of ADS. In ADS, lead-bismuth eutectic (LBE) alloy is used as a spallation target material and a core coolant. As is well known, LBE has corrosive to structural materials hence each component of the target system should provide compatibility with LBE. In addition, instrumentations for LBE are restricted by the target operation condition such as high temperature and irradiation environment. The devices for LBE have been developed individually to achieve the LBE target system. "Integrated Multi-functional MOckup for TEF-T Real-scale TArget Loop, IMMORTAL" was fabricated as a mock-up test loop of the target for the purpose of the integration testing of individually developed devices. This report describes an overview of IMMORTAL and the design of the installed devices.

JAEA Reports

Development of high temperature LBE corrosion test loop "OLLOCHI"

Saito, Shigeru; Wan, T.*; Okubo, Nariaki; Kita, Satoshi*; Obayashi, Hironari; Sasa, Toshinobu

JAEA-Technology 2021-034, 94 Pages, 2022/03

JAEA-Technology-2021-034.pdf:5.91MB

Lead-bismuth eutectic alloy (LBE) is a major candidate for a spallation target material and core coolant of an accelerator driven system (ADS) which has been developed in the Japan Atomic Energy Agency (JAEA) to transmute high-level radioactive wastes. A proton irradiation facility to build a material irradiation database for future ADS development is under considering in the J-PARC. To realize both the ADS and the above-mentioned facility, there are many issues on operational safety of LBE to be solved. Especially, corrosion data for the major materials such as T91 (Modified 9Cr-1Mo steel) and SS316L at the temperature range between 400 and 550 $$^{circ}$$C under the conditions of flowing LBE with a controlled oxygen are not sufficient to design the ADS and the facility. JAEA developed a new large-scale corrosion test loop named "OLLOCHI (Oxygen-controlled LBE LOop for Corrosion tests in HIgh-temperature)" aiming to perform the compatibility tests between the LBE and the steels, as well as to develop the LBE operation technology. OLLOCHI has a function to automatically control the oxygen concentration in LBE. The maximum temperature at the regions of high-temperature and low-temperature of the OLLOCHI are 550 $$^{circ}$$C and 450 $$^{circ}$$C respectively to cover the ADS designed condition. As a result of 2,000 hours operation, it was demonstrated that the OLLOCHI showed the designed performance. In this report, outline of the OLLOCHI, details of the components, results of characteristic tests, and the future experimental plan are described.

Journal Articles

Nuclide production cross section of $$^{nat}$$Lu target irradiated with 0.4-, 1.3-, 2.2-, and 3.0-GeV protons

Takeshita, Hayato; Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Hiroki; Nakano, Keita; Watanabe, Yukinobu*; Maekawa, Fujio

JAEA-Conf 2021-001, p.207 - 212, 2022/03

Prediction of nuclide production of spallation products by high-energy proton injection plays a fundamental and important role in shielding design of high-intensity proton accelerator facilities such as accelerator driven nuclear transmutation system (ADS). Since the prediction accuracy of the nuclear reaction models used in the production quantity prediction simulation is insufficient, it is necessary to improve the nuclear reaction models. We have measured nuclide production cross sections for various target materials with the aim of acquiring experimental data and improving nuclear reaction models. In this study, 1.3-, 2.2- and 3.0-GeV proton beams were irradiated to $$^{nat}$$Lu target, and nuclide production cross-section data were acquired by the activation method. The measured data were compared with several nuclear reaction models used in Monte Carlo particle transport calculation codes to grasp the current prediction accuracy and to study how the nuclear reaction model could be improved.

Journal Articles

CFD analysis of natural circulation in LBE-cooled accelerator-driven system

Sugawara, Takanori; Watanabe, Nao; Ono, Ayako; Nishihara, Kenji; Ichihara, Kyoko*; Hanzawa, Kohei*

Proceedings of 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) (Internet), 10 Pages, 2022/03

Japan Atomic Energy Agency (JAEA) has investigated an accelerator-driven system (ADS) to transmute minor actinides (MAs) included in high level wastes discharged from nuclear power plants. The ADS is a lead-bismuth cooled tank-type reactor with 800 MW thermal power. It is supposed that the ADS is safer than conventional critical reactors because it is operated in a subcritical state. The previous study performed the transient analyses for the typical ADS accidents such as unprotected loss of flow or beam overpower. It was shown that all calculation cases except loss of heat sink (LOHS) satisfied the no-damage criteria. To avoid the damage by LOHS, the ADS equips Direct Reactor Auxiliary Cooling System (DRACS) to remove the decay heat. The most important points of a DRACS operation are its reliability and to ensure the flowrate in a natural circulation state. This study aims to perform the CFD analysis of the natural circulation to clarify the flowrate in the ADS reactor vessel.

JAEA Reports

Development of environmental mitigation technology with novel water purification agents (Contract research); FY2020 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Shinshu University*

JAEA-Review 2021-051, 81 Pages, 2022/01

JAEA-Review-2021-051.pdf:4.03MB

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 FY2020. 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 FY2020, this report summarizes the research results of the "Development of environmental mitigation technology with novel water purification agents" conducted in FY2020. The present study aims to develop a reusable adsorbent for strontium ions through joint research between Japan and the United Kingdom, and to reduce the amount of used adsorbent generated through the decontamination process. The basic strategy of this research is to produce adsorbents and examine their Sr adsorption performance at Shinshu University. The structural analyses of the adsorbents are conducted by the Institute for Molecular Science (IMS) and the UK teams. The adsorption data and structural information are theoretically analyzed at Tohoku University with data science, leading to a new synthetic guid

Journal Articles

Design and beam dynamic studies of a 30-MW superconducting linac for an accelerator-driven subcritical system

Yee-Rendon, B.; Kondo, Yasuhiro; Maekawa, Fujio; Meigo, Shinichiro; Tamura, Jun

Physical Review Accelerators and Beams (Internet), 24(12), p.120101_1 - 120101_17, 2021/12

 Times Cited Count:2 Percentile:55.26(Physics, Nuclear)

The Japan Atomic Energy Agency (JAEA) is working on the research and development of a 30-MW continuous wave (CW) proton linear accelerator (linac) for the JAEA accelerator-driven subcritical system (ADS) proposal. The linac will accelerate a 20 mA proton beam to 1.5 GeV, using mainly superconducting cavities. The main challenge for an ADS accelerator is the high reliability required to prevent thermal stress in the subcritical reactor; thus, we pursue a robust lattice to achieve stable operation. To this end, the beam optics design reduces the emittance growth and the beam halo through the superconducting part of the linac. First, we simulated an ideal machine without any errors to establish the operation conditions of the beam. Second, we applied element errors and input beam errors to estimate the tolerance of the linac design. Finally, we implemented a correction scheme to increase the lattice tolerance by reducing the beam centroid offset on the transverse plane. Massive multiparticle simulations and a cumulative statistic of 1$$times$$10$$^{8}$$ macroparticles have shown that the JAEA-ADS linac can operate with less than 1 W/m beam losses in error scenarios.

JAEA Reports

Re-examinations of MA fuel composition for accelerator-driven system and its heat removal

Sugawara, Takanori; Moriguchi, Daisuke*; Ban, Yasutoshi; Tsubata, Yasuhiro; Takano, Masahide; Nishihara, Kenji

JAEA-Research 2021-008, 63 Pages, 2021/10

JAEA-Research-2021-008.pdf:4.43MB

This study aims to perform the neutronics calculations for accelerator-driven system (ADS) with a new fuel composition based on the SELECT process developed by Japan Atomic Energy Agency because the previous studies had used the ideal MA (minor actinide) fuel composition without uranium and rare earth elements. Through the neutronics calculations, it is shown that two calculation cases, with/without neptunium, satisfy the design criteria. Although the new fuel composition includes uranium and rare earth elements, the ADS core with the new fuel composition is feasible and consistent with the partitioning and transmutation (P&T) cycle. Based on the new fuel composition, the heat removal during fuel powder storage and fuel assembly assembling is evaluated. For the fuel powder storage, it is found that a cylindrical tube container with a length of 500 [mm] and a diameter of 11 - 21 [mm] should be stored under water. For the fuel assembly assembling, CFD analysis indicates that the cladding tube temperature would satisfy the criterion if the inlet velocity of air is larger than 0.5 [m/s]. Through these studies, the new fuel composition which is consistent with the P&T cycle is obtained and the heat removal with the latest conditions is investigated. It is also shown that the new fuel composition can be practically handled with respect to heat generation, which is one of the most difficult points in handling MA fuel.

Journal Articles

Fast fault recovery scenarios for the JAEA-ADS linac

Yee-Rendon, B.; Tamura, Jun; Kondo, Yasuhiro; Nakano, Keita; Takei, Hayanori; Maekawa, Fujio; Meigo, Shinichiro

Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.61 - 65, 2021/10

Japan Atomic Energy Agency (JAEA) is designing a 30 MW CW superconducting proton linac as a major component for the accelerator-driven subcritical system (ADS) project. The main challenge of the linac operation is the high reliability required to suppress thermal stress in the subcritical reactor. To this end, we implemented fault compensation schemes to enable a fast beam recovery; consequently, reducing the beam trip duration. This work presents strategies to increase the fault-tolerance capacity of the JAEA-ADS linac.

Journal Articles

Durability of secondary electron emission for high-intensity beam on SiC wire

Meigo, Shinichiro; Nakano, Keita; Okubo, Nariaki; Yuyama, Takahiro*; Ishii, Yasuyuki*

Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.296 - 301, 2021/10

no abstracts in English

Journal Articles

Effect of irradiation on corrosion behavior of 316L steel in lead-bismuth eutectic with different oxygen concentrations

Okubo, Nariaki; Fujimura, Yuki; Tomobe, Masakatsu*

Quantum Beam Science (Internet), 5(3), p.27_1 - 27_9, 2021/09

In an accelerator driven system (ADS), the beam window material of the spallation neutron target is heavily irradiated under severe conditions. Displacement damage and corrosion occur simultaneously because of high-energy neutron and/or proton irradiation in the lead-bismuth flow. The materials used in ADSs need to be compatible with the liquid metal, which is lead-bismuth eutectic (LBE), to prevent issues such as liquid metal embrittlement (LME) and liquid metal corrosion (LMC). In this study, the LMC behavior after ion irradiation of 316L austenitic steel is considered for self-ion irradiations followed by the corrosion tests. The 316L specimens were irradiated by 10.5 MeV-Fe$$^{3+}$$ ions at temperature of 450$$^{circ}$$C up to 50 displacement per atom (dpa). After the corrosion test at 450$$^{circ}$$C in LBE with low oxygen concentration, the surface of the non-irradiated area was not oxidized but corrosive morphology with pits, whereas the irradiated area was covered by an iron/chromium oxide layer. The surface of the irradiated area was covered by the duplex layers of iron and iron/chromium oxides in the case of higher oxygen concentration in LBE. It is suggested that irradiation can advance oxide layer formation because of enhanced Fe diffusion caused by the residual vacancies in 316L steel.

Journal Articles

Design of the MEBT for the JAEA-ADS Project

Yee-Rendon, B.; Kondo, Yasuhiro; Maekawa, Fujio; Meigo, Shinichiro; Tamura, Jun

Proceedings of 12th International Particle Accelerator Conference (IPAC 21) (Internet), p.790 - 792, 2021/08

The Medium Energy Beam Transport (MEBT) will transport a CW proton beam with a current of 20 mA and energy of 2.5 MeV from the exit of the normal conducting Radiofrequency Quadrupole (RFQ) to the superconducting Half-Wave resonator (HWR) section. The MEBT must provide a good matching between the RFQ and HWR, effective control of the emittance growth and the halo formation, enough space for all the beam diagnostics devices, among others. This work reports the first lattice design and the beam dynamics studies for the MEBT of the JAEA-ADS.

295 (Records 1-20 displayed on this page)