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JAEA Reports

Estimation of oxygen consumption amount in LBE-cooled accelerator-driven system

Sugawara, Takanori; Komatsu, Atsushi

JAEA-Research 2020-016, 44 Pages, 2021/01

JAEA-Research-2020-016.pdf:2.94MB

It is required to control the oxygen concentration in lead-bismuth eutectic (LBE) to prevent the corrosion of structures in LBE-cooled nuclear system. This study estimated the oxygen consumption amount in the LBE-cooled accelerator-driven system (ADS). We used the evaluation formula for the oxide layer thickness, which were derived by various experiments, to estimate the oxygen consumption amount. It was found that the maximum oxide layer thicknesses for the fuel assembly and the beam window were about 35 [$$mu$$m] and 20 [$$mu$$m], respectively. Based on these results, the oxygen consumption amount for the ADS plant was estimated as 30 [kg] during one cycle (one year). Through this study, it was indicated that an oxygen supply device which could supply 3-4 [g/h] oxygen in the normal operation, 150 [g/h] in the peak and about 30 [kg] during one cycle was necessary.

Journal Articles

Neutronics design for molten salt accelerator-driven system as TRU burner

Sugawara, Takanori

Annals of Nuclear Energy, 149, p.107818_1 - 107818_7, 2020/12

 Times Cited Count:0

Treatment of surplus plutonium has been one of the most important issues in the utilization of nuclear power in Japan. This study investigates a molten salt accelerator-driven system (ADS) to transmute transuranic (TRU) nuclides to address the issue. MARDS (Molten salt Accelerator Driven System) concept employs lead chloride (PbCl$$_2$$) as a fuel salt to achieve a hard spectrum. Since the fuel salt is used as a spallation target, a dedicated spallation target is not required in this concept. Furthermore, a beam window which is a boundary between an accelerator and subcritical core is designed to avoid touching the fuel salt. It mitigates the difficulties of the beam design for ADS. Neutronics calculation for the MARDS concept was performed for a condition of 400 MW thermal power with 800 MeV proton beam. The calculation results showed that the proton beam current was about 7 mA and about 4400 kg plutonium could be transmuted during 40-year operation.

Journal Articles

Error studies for the JAEA-ADS linac

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

Proceedings of 17th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.33 - 37, 2020/09

Japan Atomic Energy Agency (JAEA)- Accelerator Driven System (ADS) linac consists of a CW proton accelerator with a beam current of 20 mA driven with the energy of 1.5 GeV. Most of the beam acceleration is achieved by using superconducting cavities to obtain high acceleration efficiency at CW mode. The main superconducting linac is composed of five families of cavities (Half Wave resonators, Spokes resonators, and Elliptical cavities) with theirs respectively magnets. Due to the large beam power in the linac of 30 MW and the high reliability required for the ADS project, a robust beam optic designed is necessary to have a stable beam operation and control the beam loss power. The JAEA-ADS linac is composed of several sections and components; thus, the misalignment of these elements together with field errors enhance the beam loss rate and compromises the safety of the linac. To this end, an error linac campaign was launched to estimate the error tolerance of the components and implement a correction scheme to reduce the beam loss power around the linac.

Journal Articles

Two-parameter model for optimizing target beam distribution with an octupole magnet

Meigo, Shinichiro; Oi, Motoki; Fujimori, Hiroshi*

Physical Review Accelerators and Beams (Internet), 23(6), p.062802_1 - 062802_24, 2020/06

 Times Cited Count:0 Percentile:100(Physics, Nuclear)

As hadron accelerators for such as the ADS and spallation neutron source achieve increasing beam power, damage to targets is becoming increasingly severe. To mitigate this damage, nonlinear beam optics based on octupole magnets is attractive. Nonlinear optics can decrease the beam-focusing hazard due to failure of the rastering magnet. As a side effect of nonlinear optics, the beam size is known to expand drastically compared with linear optics. Nonlinear effects have been studied via a simplified filament model that ignores beam-divergence spread at the octupole magnet. In this study, a new generalized model is proposed for application to an octupole magnet, regardless of the filament-model approximation. It is found that the transverse distribution obtained by beam tracking can be specified by the introduction of only two parameters, namely the normalized octupole strength of $$K^{*}_8$$ and the $$cot phi$$ of the phase advance. To achieve the two antagonistic requirements of reduction of the beam-peak density and minimization of the beam loss, the transverse distribution is surveyed for a large range of beam position. It is found that a bell-shaped distribution with $$K^{*}_8 sim$$ 1 and $$cot phi sim$$ 3 can satisfy requirements. This result is applied to beam transport in the spallation neutron source at J-PARC. The calculation result given by the present model shows good agreement with the experimental data, and the peak current density is reduced by 50% compared with the linear-optics case.

Journal Articles

Direct quantitation of $$^{135}$$Cs in spent Cs adsorbent used for the decontamination of radiocesium-containing water by laser ablation inductively coupled plasma mass spectrometry

Asai, Shiho*; Ohata, Masaki*; Hanzawa, Yukiko; Horita, Takuma; Yomogida, Takumi; Kitatsuji, Yoshihiro

Analytical Chemistry, 92(4), p.3276 - 3284, 2020/02

 Times Cited Count:2 Percentile:33.83(Chemistry, Analytical)

The long-term safety assessment of spent Cs adsorbents produced during the decontamination of radiocesium-containing water at the Fukushima Daiichi nuclear power plant requires one to estimate their $$^{135}$$Cs content prior to final disposal. $$^{135}$$Cs is usually quantified by inductively coupled plasma mass spectrometry (ICP-MS), which necessitates the elution of Cs from Cs adsorbents. However, this approach suffers from the high radiation dose from $$^{137}$$Cs. To address this challenge, we herein employed laser ablation ICP-MS for direct quantitation of $$^{135}$$Cs in Cs adsorbents and used a model Cs adsorbent prepared by immersion of a commercially available Cs adsorbent into radiocesium-containing liquid waste to verify the developed technique. The use of the $$^{135}$$Cs/$$^{137}$$Cs ratio and $$^{137}$$Cs radioactivity obtained by gamma spectrometry achieved simple and precise quantitation of $$^{135}$$Cs and the resulting $$^{135}$$Cs activity of 0.36 Bq agreed well with that in the original radiocesium-containing liquid waste.

Journal Articles

Characterization of mechanical strain induced by lead-bismuth eutectic (LBE) freezing in stainless steel cup

Ohdaira, Naoya*; Saito, Shigeru

Heliyon (Internet), 6(2), p.e03429_1 - e03429_8, 2020/02

Lead-bismuth eutectic (LBE) is a candidate liquid metal coolant for a fast reactor, especially accelerator driven system (ADS). Freeze sealed valve is a candidate design to be possible to add passive safety to the reactor. On the other hand, since LBE is known that it causes expansion after its solidification, quantitative evaluation of the stress to the pipe produced by the LBE expansion should be considered. Many researchers produced related data for the expansion, however, evaluations of the strain by LBE expansion was barely reported. Therefore, the strain measurement using a stainless steel cup and the stress evaluation was performed together with visual observation using an optical microscopy. The results indicated keeping above room temperature (RT) was a significantly effective way to reduce the strain to the pipe.

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

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

Investigations of accelerator reliability and decay heat removal for accelerator-driven system

Sugawara, Takanori; Takei, Hayanori; Tsujimoto, Kazufumi

Annals of Nuclear Energy, 125, p.242 - 248, 2019/03

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

To realize the feasible accelerator-driven system (ADS) concept, the investigations for the reliable accelerator and conceptual plant design considering safety issues were performed. As the reliable accelerator concept, the double-accelerator concept was proposed to reduce the beam-trip frequency. The estimated beam-trip frequency with the double-accelerator concept using the J-PARC LINAC operation data showed that the beam-trip frequency was significantly improved with the comparison of the single accelerator result. The basic investigation of the primary reactor auxiliary coolant system (PRACS) was performed for the safety design of the LBE cooled ADS. The concept which the PRACS heat exchanger was integrated to the steam generator was proposed and the transient analysis in the loss of heat sink accident was carried out. The result presented that the decay heat removal was appropriate when the operation of the PRACS succeeded.

Journal Articles

Numerical study on the potential of cavitation damage in a lead-bismuth eutectic spallation target

Wan, T.; Naoe, Takashi; Kogawa, Hiroyuki; Futakawa, Masatoshi; Obayashi, Hironari; Sasa, Toshinobu

Materials, 12(4), p.681_1 - 681_15, 2019/02

 Times Cited Count:0 Percentile:100(Materials Science, Multidisciplinary)

Journal Articles

Online chemical adsorption studies of Hg, Tl, and Pb on SiO$$_{2}$$ and Au surfaces in preparation for chemical investigations on Cn, Nh, and Fl at TASCA

Lens, L.*; Yakushev, A.*; D$"u$llmann, Ch. E.*; Asai, Masato; Ballof, J.*; Block, M.*; David, H. M.*; Despotopulos, J.*; Di Nitto, A.*; Eberhardt, K.*; et al.

Radiochimica Acta, 106(12), p.949 - 962, 2018/12

 Times Cited Count:1 Percentile:75.54(Chemistry, Inorganic & Nuclear)

Online gas-solid adsorption studies with single atom quantities of Hg, Tl, and Pb on SiO$$_{2}$$ and Au surfaces were carried out using short-lived radioisotopes with half-lives in the range of 4-49 s. This is a model study to measure adsorption enthalpies of superheavy elements Cn, Nh, and Fl. The short-lived isotopes were produced and separated by the gas-filled recoil separator TASCA at GSI. The products were stopped in He gas, and flushed into gas chromatography columns made of Si detectors whose surfaces were covered by SiO$$_{2}$$ or Au. The short-lived Tl and Pb were successfully measured by the Si detectors with the SiO$$_{2}$$ surface at room temperature. On the other hand, the Hg did not adsorb on the SiO$$_{2}$$ surface, but adsorbed on the Au surface. The results demonstrated that the adsorption properties of short-lived Hg, Tl, and Pb could be studied with this setup, and that this method is applicable to the experiment for Cn, Nh, and Fl.

Journal Articles

Influence of gamma-ray irradiation on mechanical property of YSZ for oxygen sensors in ADS

Okubo, Nariaki; Okuno, Yasuki; Kitamura, Akane; Taguchi, Tomitsugu*

Nuclear Instruments and Methods in Physics Research B, 435, p.198 - 202, 2018/11

 Times Cited Count:0 Percentile:100(Instruments & Instrumentation)

Accelerator driven system (ADS) adopts the lead-bismuth eutectic (LBE) as both coolant and spallation target. The oxygen concentration control is one of the most important technical developments. Estimation of durability under gamma-ray irradiation for the oxygen sensor is necessary for the integrity evaluation of ADS components. The Zirconia added by Yttria (YSZ) is the main element in oxygen sensor. Effect of gamma-ray irradiation on the mechanical property and structural change for three types of YSZ with 3, 6, 8 mol% Yttria was evaluated by using 4 points bend test, XRD, SEM and Raman spectroscope. The gamma-ray irradiations were conducted at 1 and 2 kGy/h, which corresponded to the LBE activity after 1 year ADS operation. In the cases of 8Y and 6Y, degradation of strength was not measured and the fracture surface did not change the morphology. In the case of 3Y, however, the strength did not change but phase transformation from tetragonal to monoclinic crystal structure was observed in XRD results, depending on the irradiation dose. This implies that the gamma-ray irradiation causes the phase transformation in 3Y-YSZ.

Journal Articles

Characteristics of TPDN/SiO$$_{2}$$-P adsorbent for MA(III) recovery

Kofuji, Hirohide; Watanabe, So; Takeuchi, Masayuki; Suzuki, Hideya; Matsumura, Tatsuro; Shiwaku, Hideaki; Yaita, Tsuyoshi

Progress in Nuclear Science and Technology (Internet), 5, p.61 - 65, 2018/11

Journal Articles

Analytical studies of three-dimensional evaluation of radionuclide distribution in zeolite wastes through gamma scanning of adsorption vessels

Matsumura, Taichi; Nagaishi, Ryuji; Katakura, Junichi*; Suzuki, Masahide*

Nuclear Science and Engineering, 192(1), p.70 - 79, 2018/10

 Times Cited Count:1 Percentile:75.54(Nuclear Science & Technology)

The gamma-scanning of SDS (submerged demineralizer system) vessel used as a typical vessel for decontamination of radioactive water at Three Mile Island Unit 2 (TMI-2) accident was simulated in the axial and radial directions of real and cylindrical-shaped vessels by using a Monte Carlo calculation code (PHITS) on the basis of the geometrical and compositional information of vessel and gamma-scanning available in the previous reports at the accident. In the axial simulation, the true distribution of radioactive $$^{137}$$Cs in the zeolite packed bed of vessel was successfully evaluated when a correction function derived from a virtual constant distribution of $$^{137}$$Cs was applied to the reported gamma-scanning profile. In the radial simulation, the virtual disk-formed and shell-formed sources of $$^{137}$$Cs displaced in the packed bed were clearly observed from the top and bottom views of vessel. This new radial gamma-scanning indicates that the radial localization of $$^{137}$$Cs could be well observed by measuring gamma-ray from the top view of vessel during storage. We further examined the radial gamma-scanning from the side view whether the radial localization of $$^{137}$$Cs can be confirmed in the normally existing gamma-scanning room or not.

JAEA Reports

Measurement experiment of oxygen concentration in liquid lead-bismuth eutectic; Basic Tests and estimation of gamma-ray irradiation effect

Sugawara, Takanori; Kita, Satoshi*; Yoshimoto, Hidemitsu*; Okubo, Nariaki

JAEA-Technology 2018-008, 26 Pages, 2018/09

JAEA-Technology-2018-008.pdf:10.35MB

The oxygen sensors to measure the oxygen concentration in liquid LBE (lead-bismuth eutectic) were fabricated and tested for future use in LBE-cooled ADS (accelerator-driven system) or LBE test loops. The following tests were performed; estimation of catalyst application range, freeze seal structure and estimation of gamma-ray irradiation effect. For the estimation of the catalyst application range, it was confirmed that the measurement accuracy became worse in low LBE temperature as the application range became small. For the freeze seal structure, we realized the structure to prevent the LBE leakage with 0.5 MPa pressure condition. For the estimation of gamma-ray irradiation effect, the ex-situ test was carried out and it was observed that there was little effect by 4 MGy gamma-ray irradiation.

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

251 (Records 1-20 displayed on this page)