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Journal Articles

Measurement of thick target neutron yield at 180$$^{circ}$$ for a mercury target induced by 3-GeV protons

Matsuda, Hiroki; Iwamoto, Hiroki; Meigo, Shinichiro; Takeshita, Hayato*; Maekawa, Fujio

Nuclear Instruments and Methods in Physics Research B, 483, p.33 - 40, 2020/11

A thick target neutron yield for a mercury target at an angle of 180$$^{circ}$$ from the incident beam direction is measured with the time-of-flight method using a 3-GeV proton beam at the Japan Proton Accelerator Research Complex (J-PARC). Comparing the experimental result with a Monte Carlo particle transport simulation by the Particle and Heavy Ion Transport code System (PHITS) shows that there are apparent discrepancies. We find that this trend is consistent with an experimental result of neutron-induced re- action rates obtained using indium and niobium activation foils. Comparing proton-induced neutron-production double-differential cross-sections for a lead target at backward directions between the PHITS calculation and experimental data suggests that the dis- crepancies for our experiments would be linked to the neutron production calculation around 3 GeV by the PHITS spallation model and/or the calculation of nonelastic cross-sections around 3 GeV in the particle transport simulation.

Journal Articles

Measurement of displacement cross-sections of copper and iron for proton with kinetic energies in the range 0.4 - 3 GeV

Matsuda, Hiroki; Meigo, Shinichiro; Iwamoto, Yosuke; Yoshida, Makoto*; Hasegawa, Shoichi; Maekawa, Fujio; Iwamoto, Hiroki; Nakamoto, Tatsushi*; Ishida, Taku*; Makimura, Shunsuke*

Journal of Nuclear Science and Technology, 57(10), p.1141 - 1151, 2020/10

 Times Cited Count:2 Percentile:21.8(Nuclear Science & Technology)

To estimate the structural damages of materials in accelerator facilities, displacement per atom (dpa) is widely employed as a damage index, calculated based on the displacement cross-section obtained using a calculation model. Although dpa is applied as standard, the experimental data of the displacement cross-section for a proton in the energy region above 20 MeV are scarce. Among the calculation models, difference of about factor 8 exist, so that the experimental data of the cross-section are crucial to validate the model. To obtain the displacement cross-section, we conducted experiments at J-PARC. The displacement cross-section of copper and iron was successfully obtained for a proton projectile with the kinetic energies, 0.4 - 3 GeV. The results were compared with those obtained using the widely utilized Norgertt-Robinson-Torrens (NRT) model and the athermal-recombination-corrected (arc) model based on molecular dynamics. It was found that the NRT model overestimates the present displacement cross-section by 3.5 times. The calculation results obtained using with the arc model based on the Nordlund parameter show remarkable agreement with the experimental data. It can be concluded that the arc model must be employed for the dpa calculation for the damage estimation of copper and iron.

Journal Articles

Measurement of nuclide production cross section for lead and bismuth with proton in energy range from 0.4 GeV to 3.0 GeV

Matsuda, Hiroki; Meigo, Shinichiro; Iwamoto, Hiroki; Maekawa, Fujio

EPJ Web of Conferences, 239, p.06004_1 - 06004_4, 2020/09

For the Accelerator-Driven nuclear transmutation System (ADS), nuclide production yield estimation in the lead-bismuth target is important to manage the target. However, experimental data of nuclide production yield by spallation and high-energy fission reactions are scarce. In order to obtain the experimental data, we experimented in J-PARC using $$^{mathrm{nat}}$$Pb and $$^{mathrm{209}}$$Bi samples. The samples were irradiated with protons at various kinematic energy points between 0.4 and 3.0 GeV. After the irradiation, the nuclide production cross section over $$^{mathrm{7}}$$Be to $$^{mathrm{183}}$$Re was obtained by spectroscopic measurement of decay gamma-rays from the samples with HPGe detectors. The present experimental results were compared with the evaluated data (JENDL-HE/2007) and the calculation with the PHITS code and the INCL++ code. The present experiment data showed consistency with other experimental data with better accuracy than other ones. In reactions to produce light nuclides, JENDL and calculation with the PHITS and INCL++ for $$^{mathrm{7}}$$Be production agreed with the data.$$^{mathrm{22}}$$Na production, however, underestimated about 1/10 times. For middle to heavy nuclide productions cases, both calculations agreed with the experiment by a factor of two. JENDL showed lower energy having a maximum value of excitation function maximal value than the experimental data.

Journal Articles

Measurement of displacement cross section of structural materials utilized in the proton accelerator facilities with the kinematic energy above 400 MeV

Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Yosuke; Yoshida, Makoto*; Hasegawa, Shoichi; Maekawa, Fujio; Iwamoto, Hiroki; Nakamoto, Tatsushi*; Ishida, Taku*; Makimura, Shunsuke*

EPJ Web of Conferences, 239, p.06006_1 - 06006_4, 2020/09

R&D of the beam window is crucial in the ADS, which serves as a partition between the accelerator and the target region. Although the displacement per atom (DPA) is used to evaluate the damage on the window, experimental data on the displacement cross section is scarce in the energy region above 20 MeV. We started to measure the displacement cross section for the protons in the energy region between 0.4 to 3 GeV. The displacement cross section can be derived by resistivity change divided by the proton flux and the resistivity change per Frankel pair on cryo-cooled sample to maintain damage. Experiments were conducted at the 3 GeV proton synchrotron at the J-PARC Center, and copper was used as samples. As a result of comparison between the present experiment and the calculation of the NRT model, which is widely used for calculation of the displacement cross section, it was found that the calculation of the NRT model overestimated the experiment by about 3 times.

Journal Articles

Measurement of displacement cross section of structural materials utilized in the proton accelerator facilities with the kinematic energy above 400 MeV

Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Yosuke; Yoshida, Makoto*; Hasegawa, Shoichi; Maekawa, Fujio; Iwamoto, Hiroki; Nakamoto, Tatsushi*; Ishida, Taku*; Makimura, Shunsuke*

JPS Conference Proceedings (Internet), 28, p.061004_1 - 061004_6, 2020/02

no abstracts in English

Journal Articles

Current Status of R&D and PIE Program for ADS Material Development in JAEA

Saito, Shigeru; Okubo, Nariaki; Obayashi, Hironari; Wan, T.; Sugawara, Takanori; Sasa, Toshinobu; Maekawa, Fujio

JPS Conference Proceedings (Internet), 28, p.071003_1 - 071003_6, 2020/02

Japan Atomic Energy Agency (JAEA) proposes transmutation of minor actinides (MA) by accelerator-driven systems (ADS). The ADS designed by JAEA is a system composed by LBE (Lead-Bismuth Eutectic) spallation target and a subcritical core. In the ADS, a beam window (BW) is exposed in complex field of heavy irradiation by proton/neutron and corrosion by flowing LBE. To develop ADS structural materials, it is of critical importance to investigate materials used in such environment. Thus, JAEA plans to construct a proton irradiation facility at the J-PARC to prepare an irradiation database for candidate ADS structural materials and to investigate irradiation effects in flowing LBE environment. In this paper, giving a whole scope of the JAEA ADS development, some results of experimental measurements and the specific program for planed R&D will be presented.

Journal Articles

Beam optics design of the superconducting region of the JAEA ADS

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

Journal of Physics; Conference Series, 1350(1), p.012120_1 - 012120_5, 2019/12

Journal Articles

Electromagnetic design of the low beta cavities for the JAEA ADS

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

Journal of Physics; Conference Series, 1350(1), p.012197_1 - 012197_7, 2019/12

Journal Articles

Design of the elliptical superconducting cavities for the JAEA ADS

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

Journal of Physics; Conference Series, 1350(1), p.012198_1 - 012198_6, 2019/12

Journal Articles

Electromagnetic design of the prototype spoke cavity for the JAEA-ADS linac

Tamura, Jun; Kondo, Yasuhiro; Yee-Rendon, B.; Meigo, Shinichiro; Maekawa, Fujio; Hasegawa, Kazuo; Kako, Eiji*; Umemori, Kensei*; Sakai, Hiroshi*; Konomi, Taro*

Proceedings of 19th International Conference on RF Superconductivity (SRF 2019) (Internet), p.399 - 402, 2019/11

Journal Articles

The Analytical study of inventories and physicochemical configuration of spallation products produced in Lead-Bismuth Eutectic of Accelerator Driven System

Miyahara, Shinya*; Ohdaira, Naoya*; Arita, Yuji*; Maekawa, Fujio; Matsuda, Hiroki; Sasa, Toshinobu; Meigo, Shinichiro

Nuclear Engineering and Design, 352, p.110192_1 - 110192_8, 2019/10

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

Lead-Bismuth Eutectic (LBE) is used as a spallation neutron target and coolant materials of Accelerator Driven System (ADS), and many kinds of elements are produced as spallation products. It is important to evaluate the release and transport behavior of the spallation products in the LBE. The inventories and the physicochemical composition of the spallation products produced in LBE have been investigated for an LBE loop in the ADS Target Test Facility (TEF-T) in J-PARC. The inventories of the spallation products in the LBE were estimated using the PHITS code. The physicochemical composition of the spallation products in the LBE was calculated using the Thermo-Calc code under the conditions of the operation temperatures of LBE from 350$$^{circ}$$C to 500$$^{circ}$$C and the oxygen concentrations in LBE from 10 ppb to 1 ppm. The calculation showed that the 5 elements of Rb, Tl, Tc, Os, Ir, Pt, Au and Hg were soluble in LBE under the all given conditions and any kinds of compound were not formed in LBE. It was suggested that the oxides of Ce, Sr, Zr and Y were stable as CeO$$_{2}$$, SrO, ZrO$$_{2}$$ and Y$$_{2}$$O$$_{3}$$ in the LBE.

Journal Articles

Cavity and optics design of the accelerator for the JAEA-ADS project

Yee-Rendon, B.; Tamura, Jun; Kondo, Yasuhiro; Hasegawa, Kazuo; Maekawa, Fujio; Meigo, Shinichiro; Oguri, Hidetomo

Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.107 - 111, 2019/07

Journal Articles

Shielding

Maekawa, Fujio

Hamon, 28(4), p.208 - 211, 2018/11

Adequate shielding of neutrons and associated $$gamma$$-rays is of importance from viewpoints of the radiation safety of researchers and good experimental data taking by reducing the background. This article introduces basics of neutron shielding, physics and suitable materials for neutron and $$gamma$$-ray shielding, and an example of conceptual shielding design for the 1-MW spallation neutron source of J-PARC MLF.

Journal Articles

Accelerator Driven nuclear transmutation System (ADS)

Maekawa, Fujio

Koenerugi Kasokuki Semina, OHO '18 Jukoyo Tekisuto, 11 Pages, 2018/09

no abstracts in English

Journal Articles

Measurement of displacement cross-section for structural materials in High-Power Proton Accelerator Facility

Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Yosuke; Iwamoto, Hiroki; Hasegawa, Shoichi; Maekawa, Fujio; Yoshida, Makoto*; Ishida, Taku*; Makimura, Shunsuke*; Nakamoto, Tatsushi*

Proceedings of 9th International Particle Accelerator Conference (IPAC '18) (Internet), p.499 - 501, 2018/06

no abstracts in English

Journal Articles

J-PARC Transmutation Experimental Facility Program

Maekawa, Fujio; Transmutation Expeimental Facility Design Team

Plasma and Fusion Research (Internet), 13(Sp.1), p.2505045_1 - 2505045_4, 2018/05

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 promoting development of the P-T technology by using an accelerator driven system (ADS). To facilitate the development, we have a plan to construct the Transmutation Experimental Facility (TEF) as one of experimental facilities of J-PARC (Japan Proton Accelerator Research Complex). TEF consists of two facilities: the ADS Target Test Facility (TEF-T) and the Transmutation Physics Experimental Facility (TEF-P). Recent progress in design and R&D efforts toward construction of J-PARC TEF will be presented.

JAEA Reports

Assessment of lead-bismuth-eutectic leak at ADS Target Test Facility in Transmutation Experimental Facility of J-PARC

Iwamoto, Hiroki; Maekawa, Fujio; Matsuda, Hiroki; Meigo, Shinichiro

JAEA-Technology 2017-029, 39 Pages, 2018/01

JAEA-Technology-2017-029.pdf:2.68MB

Under an assumption that an incident of lead-bismuth eutectic (LBE) leak from an LBE circulation system occurred during a 250-kW beam operation, an estimation of radiation dose at the site boundary for the ADS Target Test Facility (TEF-T) in Transmutation Experimental Facility (TEF) of J-PARC was conducted using various conservative assumptions. As a result, the radiation dose at the site boundary was estimated to be about 660 $$mu$$Sv, which were dominated by mercury, noble gas, and iodine produced as spallation products from the LBE. Even though the incident scenario was made conservatively, it was shown that the estimated total dose was lower than the annual radiation dose due to natural sources, and the TEF-T has sufficient safety margin for the leak of radioactivity.

Journal Articles

J-PARC transmutation experimental facility program and situation of the world

Maekawa, Fujio; Sasa, Toshinobu

Enerugi Rebyu, 37(9), p.15 - 18, 2017/08

Accelerator driven nuclear transmutation systems (ADS) are under development for reducing nuclear waste. The J-PARC Transmutation Experimental Facility program and situation of the world for the ADS development are introduced.

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:10 Percentile:14.9(Nuclear Science & Technology)

JAEA Reports

Measurement of high-energy neutron fluxes and spectra around the J-PARC mercury spallation neutron target using multi-foil activation method

Kasugai, Yoshimi; Harada, Masahide; Kai, Tetsuya; Oi, Motoki; Meigo, Shinichiro; Maekawa, Fujio

JAEA-Data/Code 2015-033, 28 Pages, 2016/03

JAEA-Data-Code-2015-033.pdf:1.78MB

The high-energy neutron fluxes and spectra around the mercury spallation neutron source at MLF of J-PARC were measured by the multi-foil activation method. The threshold energies of neutron reactions utilized in this experiment covered from 0.1 to 50 MeV. The foil irradiation was carried out on the first beam-run of MLF from May 30th to 31th, 2008. After the irradiation, the induced radioactivity of each foil was measured using an HPGe detector, and the neutron-induced reaction-rate distribution around the mercury target was determined. Using these data, the high-energy neutron fluxes and spectra were deduced with unfolding method in which the neutron spectra calculated with PHITS code were used as the initial-guess spectra. By comparison between the initial and the unfolded spectra, it was shown that most of the calculation results, which had been the basis of the neutronics design of the MLF target assembly, were consistent with the experimental data within $$pm$$30%.

304 (Records 1-20 displayed on this page)