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JAEA Reports

Neutronic analysis of beam window and LBE of an Accelerator-Driven System

Nakano, Keita; Iwamoto, Hiroki; Nishihara, Kenji; Meigo, Shinichiro; Sugawara, Takanori; Iwamoto, Yosuke; Takeshita, Hayato*; Maekawa, Fujio

JAEA-Research 2021-018, 41 Pages, 2022/03


Neutronic analysis of beam window of the Accelerator-Driven System (ADS) proposed by Japan Atomic Energy Agency (JAEA) has been conducted using PHITS and DCHAIN-PHITS codes. We investigate gas production of hydrogen and helium isotopes in the beam window, displacement per atom of beam window material, and heat generation in the beam window. In addition, distributions of produced nuclides, heat density, and activity are derived. It was found that at the maximum 12500 appm H production, 1800 appm He production, and damage of 62.1 DPA occurred in the beam window by the ADS operation. On the other hand, the maximum heat generation in the beam window was 374 W/cm$$^3$$. In the analysis of LBE, $$^{206}$$B and $$^{210}$$Po were found to be the dominant nuclides in decay heat and radioactivity. Furthermore, the heat generation in the LBE by the proton beam was maximum around 5 cm downstream of the beam window, which was 945 W/cm$$^3$$.

Journal Articles

A Plan of materials irradiation facility at J-PARC for development of ADS and high-power accelerator facilities

Maekawa, Fujio

JPS Conference Proceedings (Internet), 33, p.011042_1 - 011042_6, 2021/03

Development of beam window (BW) materials is one of crucial issues in development of accelerator driven nuclear transmutation systems (ADS). The BW is exposed to high energy protons and spallation neutrons, and also to corrosive lead-bismuth eutectic (LBE) alloy at high temperature of about 500$$^{circ}$$C. Recently, not only high-power accelerators but also high-power targets are the rate-limiting factor for increasing the power of accelerator facilities in terms of radiation damage and heat removal. To study radiation damage on BW and target materials for high-power accelerator facilities including ADS, we are planning a materials irradiation facility by utilizing the proton beam of 400 MeV and 250 kW provided by the J-PARC's Linac. The target is flowing LBE alloy which is a candidate target and coolant material of ADS. When a steel sample is irradiated in the target for one year, the sample receives radiation damage of about 10 dpa at maximum which is equivalent to the yearly radiation damage of ADS's BW. In the current facility concept, the facility is equipped with a hot-laboratory for efficient post-irradiation examination. The facility will be outlined in this presentation.

Journal Articles

Research and development activities for accelerator-driven system in JAEA

Sugawara, Takanori; Takei, Hayanori; Iwamoto, Hiroki; Oizumi, Akito; Nishihara, Kenji; Tsujimoto, Kazufumi

Progress in Nuclear Energy, 106, p.27 - 33, 2018/07

 Times Cited Count:9 Percentile:81.13(Nuclear Science & Technology)

The Japan Atomic Energy Agency (JAEA) has investigated an accelerator-driven system (ADS) to transmute minor actinides which will be partitioned from the high level waste. There are various inherent issues for the research and development on the ADS. The recent two activities to realize a feasible and reliable ADS concept are introduced in this paper. For the feasibility, the design of a beam window which is a boundary of the accelerator and the subcritical core, is one of the most important issues. To mitigate the design condition of the beam window, namely to reduce the proton beam current, the subcritical core concept with subcriticality adjustment rods were investigated. For the reliability, the beam-trip is the inherent and serious issue for the ADS design because it induces rapid temperature change to coolant and structures in the subcritical core. To improve the beam-trip frequencies, a double-accelerator concept was proposed and its beam-trip frequency was estimated.

Journal Articles

Impact of PHITS spallation models on the neutronics design of an accelerator-driven system

Iwamoto, Hiroki; Nishihara, Kenji; Iwamoto, Yosuke; Hashimoto, Shintaro; Matsuda, Norihiro; Sato, Tatsuhiko; Harada, Masahide; Maekawa, Fujio

Journal of Nuclear Science and Technology, 53(10), p.1585 - 1594, 2016/10

 Times Cited Count:11 Percentile:81.57(Nuclear Science & Technology)

Journal Articles

J-PARC transmutation experimental facility programme

Sasa, Toshinobu; Takei, Hayanori; Saito, Shigeru; Obayashi, Hironari; Nishihara, Kenji; Sugawara, Takanori; Iwamoto, Hiroki; Yamaguchi, Kazushi; Tsujimoto, Kazufumi; Oigawa, Hiroyuki

NEA/CSNI/R(2015)2 (Internet), p.85 - 91, 2015/06

Nuclear transmutation got much interested as an effective option of nuclear waste management. Japan Atomic Energy Agency (JAEA) proposes the transmutation of minor actinides (MA) by accelerator-driven system (ADS) using lead-bismuth alloy (Pb-Bi). To obtain the data for ADS design, JAEA plans to build a Transmutation Experimental Facility (TEF) in the J-PARC project. TEF consists of two buildings, an ADS target test facility (TEF-T) with 400MeV-250kW Pb-Bi target, and a Transmutation Physics Experimental Facility (TEF-P), which set up a fast critical assembly driven by low power proton beam with MA fuel. In TEF-T, irradiation test for materials, and engineering tests for Pb-Bi target operation will be performed. Various research plans such as nuclear data measurements have been proposed and layout of the experimental hall are underway. In the presentation, roadmap to establish the ADS transmutor and latest design activities for TEF construction will be summarized.

Journal Articles

Measurement of LBE flow velocity profile by UDVP

Kikuchi, Kenji; Takeda, Yasushi*; Obayashi, Hiroo*; Tezuka, Masao*; Sato, Hiroshi

Journal of Nuclear Materials, 356(1-3), p.273 - 279, 2006/09

 Times Cited Count:8 Percentile:52.29(Materials Science, Multidisciplinary)

Measurements of LBE flow velocity profile were realized in the spallation target model by the ultrasonic Doppler velocity profile technique. Hitherto, it has not yet been done well because both of poor wetting property of LBE with stainless steels and poor performance of supersonic probes at high temperatures. Measurement was made for a return flow in the target model, which has coaxially arranged annular and tube channels. The electromagnetic pump generates LBE flow and the flow rate was measured by the electromagnetic flow meter. Measurement results show that re-circulation occurred near the surface of beam window, which might affect a heat transfer of target container.

Journal Articles

Critical $$beta$$ analyses with ferromagnetic and plasma rotation effects and wall geometry for a high $$beta$$ steady state tokamak

Kurita, Genichi; Bialek, J.*; Tsuda, Takashi; Azumi, Masafumi*; Ishida, Shinichi; Navratil, G. A.*; Sakurai, Shinji; Tamai, Hiroshi; Matsukawa, Makoto; Ozeki, Takahisa; et al.

Nuclear Fusion, 46(2), p.383 - 390, 2006/02

 Times Cited Count:9 Percentile:33.28(Physics, Fluids & Plasmas)

It is shown that critical beta is decreased by ferromagnetic effect by about 8% for $$mu$$/$$mu$$$$_{0}$$$$sim$$2, $$mu$$ and $$mu$$$$_{0}$$ denoting the permeability of ferromagnetic wall and vacuum, respectively, for tokamak of aspect ratio 3. The existence of the stability window for resistive wall mode opened by both effects of the toroidal plasma rotation and the plasma dissipation, which was not observed for high aspect ratio tokamak, is found for tokamak of aspect ratio 3. The effect of ferromagnetism on them is also investigated. The critical beta analyses of NCT (National Centralized Tokamak) plasma using VALEN code are started with stabilizing plate and vacuum vessel geometry with finite resistivity, and the results for passive effect of stabilizing plate are obtained. The calculations including stabilizing effect of the vacuum-vessel and also active feedback control are also performed for present design of NCT plasma.

Journal Articles

Development of reliable diamond window for EC launcher on fusion reactors

Takahashi, Koji; Illy, S.*; Heidinger, R.*; Kasugai, Atsushi; Minami, Ryutaro; Sakamoto, Keishi; Thumm, M.*; Imai, Tsuyoshi

Fusion Engineering and Design, 74(1-4), p.305 - 310, 2005/11

 Times Cited Count:13 Percentile:68.06(Nuclear Science & Technology)

A new diamond window with the copper-coated edge for an EC launcher is developed. The diamond window is designed to cool its disk edge. Since Cu is coated at the entire edge, ingress of cooling water into a transmission line in case of failure on the edge is negligible. In addition, corrosion of Al blaze between the edge and the Inconel cuffs can be avoided. A 170GHz, RF transmission experiment equivalent to a MW-level transmission was carried out to investigate the capability of the edge cooling. The transmission power and pulse are 55kW and 3sec, respectively. Temperature increase was 45$$^{circ}$$C and alomost became constant. Thermal calculation with tan$$delta$$ of 4.4$$times$$10$$^{-4}$$ and thermal conductivity of 1.9kW/m/K agrees with the experiment. Since tan$$delta$$ of the diamond is much higher than the actual one (tan$$delta$$=2$$times$$10$$^{-5}$$), the temperature increase corresponds to that of 1MW transmission. It concludes that the Cu coating dose not degrade the edge cooling capability and improves the reliability of the diamond window.

Journal Articles

Temperature dependence of the transmission loss in KU-1 and KS-4V quartz glasses for the ITER diagnostic window

Nishitani, Takeo; Sugie, Tatsuo; Morishita, Norio; Yokoo, Noriko*

Fusion Engineering and Design, 74(1-4), p.871 - 874, 2005/11

 Times Cited Count:13 Percentile:68.06(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Design study around beam window of ADS

Oigawa, Hiroyuki; Tsujimoto, Kazufumi; Kikuchi, Kenji; Kurata, Yuji; Sasa, Toshinobu; Umeno, Makoto*; Nishihara, Kenji; Saito, Shigeru; Mizumoto, Motoharu; Takano, Hideki*; et al.

Proceedings of 4th International Workshop on the Utilisation and Reliability of High Power Proton Accelerators, p.325 - 334, 2005/11

The Japan Atomic Energy Research Institute (JAERI) is conducting the research and development (R&D) on the Accelerator-Driven Subcritical System (ADS) for the effective transmutation of minor actinides (MAs). The ADS proposed by JAERI is the 800 MWth, Pb-Bi cooled, tank-type subcritical reactor loaded with (MA+Pu) nitride fuel. The Pb-Bi is also used as the spallation target. In this study, the feasibility of the ADS was discussed with putting the focus on the design around the beam window. The partition wall was placed between the target region and the ductless-type fuel assemblies to keep the good cooling performance for the hot-spot fuel pin. The flow control nozzle was installed to cool the beam window effectively. The thermal-hydraulic analysis showed that the maximum temperature at the outer surface of the beam window could be repressed below 500 $$^{circ}$$C even in the case of the maximum beam power of 30 MW. The stress caused by the external pressure and the temperature distribution of the beam window was also below the allowable limit.

Journal Articles

Research and development program on accelerator driven subcritical system in JAERI

Tsujimoto, Kazufumi; Oigawa, Hiroyuki; Ouchi, Nobuo; Kikuchi, Kenji; Kurata, Yuji; Mizumoto, Motoharu; Sasa, Toshinobu; Nishihara, Kenji; Saito, Shigeru; Umeno, Makoto*; et al.

Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 6 Pages, 2005/10

The Japan Atomic Energy Research Institute (JAERI) has been proceeding with the research and development (R&D) on accelerator-driven subcritical system (ADS). The ADS proposed by JAERI is a lead-bismuth (Pb-Bi) eutectic cooled fast subcritical core with 800 MWth. To realize such an ADS, some technical issues should be studied, developed and demonstrated. JAERI has started a comprehensive R&D program since the fiscal year of 2002 to acquire knowledge and elemental technology that are necessary for the validation of engineering feasibility of the ADS. The first stage of the program had been continued for three years. The program is conducted by JAERI, and many institutes, universities and private companies were involved. Items of R&D are concentrated on three technical areas peculiar to the ADS: (1) superconducting linear accelerator (SC-LINAC), (2) Pb-Bi eutectic as spallation target and core coolant, and (3) subcritical core design and technology. In the present work, the outline and the results in the first stage of the program are reported.

Journal Articles

Effect of proton beam profile on stress in JSNS target vessel

Kogawa, Hiroyuki; Ishikura, Shuichi*; Sato, Hiroshi; Harada, Masahide; Takatama, Shunichi*; Futakawa, Masatoshi; Haga, Katsuhiro; Hino, Ryutaro; Meigo, Shinichiro; Maekawa, Fujio; et al.

Journal of Nuclear Materials, 343(1-3), p.178 - 183, 2005/08

 Times Cited Count:8 Percentile:51.68(Materials Science, Multidisciplinary)

A cross-flow type (CFT) mercury target with flow guide blades, which has been developed for JSNS, can suppress the generation of stagnant flow region especially near the beam window where the peak heat density is generated due to spallation reaction. Then, a flat type beam window has been applied to the CFT target from the viewpoint of suppressing dynamic stress caused by a pressure wave, which has been estimated with a mercury model of the linear equation of state. The recent experimental results obtained by using a proton beam incidents to mercury led that a cutoff pressure model in the equation of state of mercury caused a suitable dynamic stress with experimental results. Dynamic stress analyses were carried out with the cutoff pressure model, in which the negative pressure less than 0.15 MPa was not generated. The generated dynamic stress in the flat beam window became much larger than that in a semi-cylindrical type window. However, the generated stress in the semi-cylindrical type beam window was over the allowable stress of SS316L under the peak heat density of 668 W/cc. In order to decrease the dynamic stress in the semi-cylindrical beam window, the incident proton beam was defocused to decrease the peak heat density down to 218 W/cm$$^{3}$$. As a result, the dynamic stress could be suppressed less than the allowable stress. On the other hand, due to defocus of the proton beam, high heat density was generated on the end of the flow guide blades, which caused high thermal stress exceeding the allowable stress. To decrease the thermal stress, several shapes of the blade ends were studied analytically, which were selected so as not to affect the mercury flow distribution. A simple thin-end blade showed low thermal stress below the allowable stress.

Journal Articles

R&D activities on accelerator-driven transmutation system in JAERI

Oigawa, Hiroyuki; Tsujimoto, Kazufumi; Kikuchi, Kenji; Kurata, Yuji; Sasa, Toshinobu; Umeno, Makoto*; Saito, Shigeru; Nishihara, Kenji; Mizumoto, Motoharu; Takano, Hideki*; et al.

EUR-21227 (CD-ROM), p.483 - 493, 2005/00

JAERI is conducting the study on the dedicated transmutation system using the accelerator driven subcritical system (ADS). A subcritical reactor with the thermal power of 800 MW has been proposed. Many research and development activities including the conceptual design study are under way and planned at JAERI to examine the feasibility of the ADS. In the field of the proton accelerator, a superconducting LINAC is being developed. In the field of the spallation target using lead-bismuth eutectic (LBE), material corrosion, thermal-hydraulics, polonium behavior, and irradiation effect on materials are being studied. Moreover, in the framework of the J-PARC project, JAERI plans to construct the Transmutation Experimental Facility (TEF) to study the feasibility of the ADS using a high-energy proton beam and nuclear fuel and to establish the technology for the LBE spallation target and relevant materials.

Journal Articles

Development of EC launcher components for ITER

Takahashi, Koji; Kobayashi, Noriyuki*; Kasugai, Atsushi; Sakamoto, Keishi

Journal of Physics; Conference Series, 25, p.75 - 83, 2005/00

Recent progress of the development on the ITER equatorial EC launcher components, such as the steering mirrors, its drive system, the waveguide components and the diamond vacuum windows, is reported. Thermmo-mechanical analysis of the recent mirror design shows that maximum temperature increase of 187$$^{circ}$$C at the reflecting surface and maximum stress of 242MPa at the inner surface of the cooling tube are obtained. In the cyclic test of the spiral tube mock-up, the cyclic number of 1.3$$times$$10$$^{6}$$ is succeeded without failure. In the window development, the fabrication of the Cu-coated edge diamond window and the high power transmission test were done. The Cu-coating on the disk edge can avoid water ingress in the launcher (vessel) under the assumption of the crack formation toward edge. Transmission experiment indicative to 1.2MW, was carried out. Temperature increase of 50$$^{circ}$$C agrees with the calculation. It concludes that the Cu-coated window is capable of MW-level transmission and improves its reliability.

JAEA Reports

Report of the 13th IEA Workshop on Radiation Effects in Ceramic Insulators; December 9, 2003, Kyoto (Cooperative research)

Department of Fusion Engineering Research

JAERI-Review 2004-004, 96 Pages, 2004/03


no abstracts in English

Journal Articles

Application of diamond window for infrared laser diagnostics in a tokamak device

Kawano, Yasunori; Chiba, Shinichi; Inoue, Akira*

Review of Scientific Instruments, 75(1), p.279 - 280, 2004/01

 Times Cited Count:11 Percentile:53.04(Instruments & Instrumentation)

It has been successful to apply CVD diamond plate as the vacuum window for infrared CO$$_{2}$$ laser interferometry and polarimetry for electron density measurement in the JT-60U tokamak. In comparison with to use the conventional zinc-selenide windows, the Faraday rotation component at diamond windows was small as negligible. This resulted in the improvement of the Faraday rotation measurement for a tokamak plasma by polarimetry.

Journal Articles

Target station design of 1 MW spallation neutron source at the high intensity proton accelerator facilities J-PARC

Takada, Hiroshi; Maekawa, Fujio; Honmura, Shiro*; Yoshida, Katsuhiko*; Teraoku, Takuji*; Meigo, Shinichiro; Sakai, Akio*; Kasugai, Yoshimi; Kanechika, Shuji*; Otake, Hidenori*; et al.

Proceedings of ICANS-XVI, Volume 3, p.1115 - 1125, 2003/07

no abstracts in English

Journal Articles

Design of beam incident monitor for spallation neutron target of JSNS

Meigo, Shinichiro; Harada, Masahide; Teraoku, Takuji*; Maekawa, Fujio

Proceedings of ICANS-XVI, Volume 3, p.1175 - 1180, 2003/07

It is important to monitor the proton beam for the high intensity pulse spallation target. Especially for the beam halo, which may irradiate the bulk surrounding the target, it is important to be observed to prevent causing heat spot in the shielding bulk. At JSNS, a proton beam monitors are located at front of the target. These monitors are assembled with the proton beam window. Since this scheme increases the radiation on the monitor due to the beam loss at the windows, it may arise heat deposition on the monitor. Therefore, heat deposition is calculated with NMTC/JAM. It is found that the heat deposition for normal operation is less than 0.1 W/cc.

Journal Articles

Structural integrity of beam window of mercury target

Kogawa, Hiroyuki; Ishikura, Shuichi*; Futakawa, Masatoshi; Kaminaga, Masanori; Hino, Ryutaro

Proceedings of 11th International Conference on Nuclear Engineering (ICONE-11) (CD-ROM), 7 Pages, 2003/04

The developments of a MW-class spallation neutron source facility are being carried out under the high-intensity proton accelerator project promoted by JAERI and KEK. A mercury target will be used as a neutron source in the facility. The mercury target vessel made of 316LSS will be subjected to pressure wave generated by rapid thermal expansion of mercury due to a pulsed proton beam injection. The pressure wave will make huge stress on the vessel and will deform the vessel, which would cause cavitation in mercury. To estimate the structural integrity of the mercury target vessel, especially beam window, dynamic stress behaviors due to 1MW-pulsed proton beam injection were analyzed by using FEM code. In the analyses, two types of the target vessels with semi-cylindrical and flat type windows were used as analytical models. As the results, it has been understood that the stress generated in the beam window by the pressure wave could be treated as the secondary stress. Also it was confirmed that the flat type window would be more advantageous from the structural viewpoint than the semi-cylindrical type window.

JAEA Reports

Structual design study of a proton beam window for a 1-MW spallation neutron source

Teraoku, Takuji*; Terada, Atsuhiko*; Maekawa, Fujio; Meigo, Shinichiro; Kaminaga, Masanori; Ishikura, Shuichi*; Hino, Ryutaro

JAERI-Tech 2003-026, 77 Pages, 2003/03


A 1-MW spallation neutron source aiming at materials and life science researches will be constructed under the JAERI-KEK Proton Accelerator Project(J-PARC). The proton beam window functions as a boundary wall between a high vacuum area and a helium atmosphere and it is cooled by light water because high heat-density is generated in the window material by interactions with the proton beam. Then, uniformity of the water flow is requested at the window to suppress a hot-spot that causes excessive thermal stress and cooling water boiling. Also, the window has to be strong enough in its structure for inner stress due to water pressure and thermal stress due to heat generation. In this report, we propose two types of proton beam windows, flat-type and curved-type. We evaluated the strength of structure and thermal hydraulic analysis. As a result, it was found that sufficient heat removal was assured with uniform water flow at the window, and the stress could be maintained below allowable stress values. Accordingly, it was confirmed that the proton beam window designs were feasible.

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