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Takei, Hayanori
Journal of Nuclear Science and Technology, 14 Pages, 2023/00
Times Cited Count：0 Percentile：0.18(Nuclear Science & Technology)In the proton linear accelerator (linac), the proton beam is unexpectedly interrupted due to the electrical discharge originating from the radio frequency, failure of the device/equipment, or other factors. Do these beam trips occur randomly? Conventionally, it has been implicitly assumed that beam trips occur randomly. In this study, we investigated whether beam trips in the linac of the Japan Proton Accelerator Research Complex (J-PARC) occur randomly to estimate the beam trip frequency in a superconducting proton linac for an accelerator-driven nuclear transmutation system. First, the J-PARC linac was classified into five subsystems. Then, the reliability function for the operation time in each subsystem was obtained using the Kaplan--Meier estimation, a reliability engineering methods. Using this reliability function, the randomness of beam trips was examined. Analysis of five-year operational data for five subsystems of the J-PARC linac showed that beam trips occurred randomly in some subsystems. However, beam trips did not occur randomly in many subsystems of the proton linac, including the ion source and the acceleration cavity, the primary subsystems of the proton linac.
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.
Maekawa, Fujio
Purazuma, Kaku Yugo Gakkai-Shi, 98(5), p.201 - 205, 2022/05
The nuclear transmutation technology is a powerful solution to the "nuclear waste" problem that accompanies nuclear power generation. The Accelerator Driven System (ADS), which combines a high-intensity accelerator and a subcritical core, is a promising tool for nuclear transmutation. In this paper, we will explain the significance and principle of nuclear transmutation by ADS, design examples of ADS, partitioning and transmutation technology and its effects, required performance of high-intensity accelerators, overseas trends, etc.
Maekawa, Fujio; Takei, Hayanori
Purazuma, Kaku Yugo Gakkai-Shi, 98(5), p.206 - 210, 2022/05
In developing an accelerator-driven nuclear transmutation system (ADS), it is necessary to solve technical issues related to proton beams, such as the development of materials that can withstand high-intensity proton beams and the characterization of subcritical cores driven by proton beams. Therefore, at the high-intensity proton accelerator facility J-PARC, a transmutation experimental facility that actually conducts various tests using a high-intensity proton beam is being planned. This paper introduces the outline and future direction of the transmutation experimental facility.
Sasa, Toshinobu
Purazuma, Kaku Yugo Gakkai-Shi, 98(5), p.211 - 215, 2022/05
Lead-bismuth eutectic (LBE) alloy is promising as a spallation target for next-generation reactor coolants and accelerator drive systems (ADS) due to its nuclear and chemical properties. LBE is a heavy metal, and it has good properties both as a spallation target and as a coolant for nuclear transmutation systems of long-lived radioactive nuclei. On the other hand, to improve compatibility with structural materials is one of the major issues in its utilization. The latest research results such as high-temperature operation of LBE and oxygen concentration control to ensure corrosion resistance with the aim of early commercialization of nuclear conversion technology by ADS is introduced.
Nakano, Keita; Matsuda, Hiroki*; Meigo, Shinichiro; Iwamoto, Hiroki; Takeshita, Hayato*; Maekawa, Fujio
JAEA-Research 2021-014, 25 Pages, 2022/03
JAEA-Research-2021-014.pdf:2.1MB
For the development of accelerator-driven transmutation system (ADS), measurement of nuclide production cross-sections in proton-induced reactions on 
Be, C, 
Al, 
Sc, and V have been performed. The measured data are compared with the calculations by the latest nuclear reaction models and with the nuclear data library to investigate the reproducibilities.
Ueta, Shohei; Sasaki, Koei; Arita, Yuji*
Nihon Genshiryoku Gakkai-Shi ATOMO
, 63(8), p.615 - 620, 2021/08
no abstracts in English
CsShibahara, Yuji*; Nakamura, Shoji; Uehara, Akihiro*; Fujii, Toshiyuki*; Fukutani, Satoshi*; Kimura, Atsushi; Iwamoto, Osamu
Journal of Radioanalytical and Nuclear Chemistry, 325(1), p.155 - 165, 2020/07
Times Cited Count：8 Percentile：71.58(Chemistry, Analytical)The measurements of isotopic ratios of Cs samples by thermal ionization mass spectrometry were performed for the analysis of their samples used to evaluate nuclear data obtained for Cs. To obtain a high intensity and stable ion beam, the effects of additive agents on the ionization of Cs were examined. The effect of silicotungstic acid on the ionization of Cs was the largest among the additive agents studied in the present study, while the silicotungstic acid also showed the largest isobaric interference of polyatomic ions. It was demonstrated that as small as 2
10
g of a Cs sample was sufficient to achieve the analytical precision required to measure the Cs/
Cs ratio in the case where an additive agent of TaO/glucose was employed. After examining of the analytical conditions, such as the interference effect due to Ba, the measurements of the isotopic ratios of two Cs samples used in our study using TIMS were conducted, and it was discussed how much the ratios contributed to evaluation of the neutron capture cross-section of Cs.
Nakamura, Shoji; Shibahara, Yuji*; Kimura, Atsushi; Iwamoto, Osamu; Uehara, Akihiro*; Fujii, Toshiyuki*
Journal of Nuclear Science and Technology, 57(4), p.388 - 400, 2020/04
Times Cited Count：3 Percentile：31.89(Nuclear Science & Technology)The thermal-neutron capture cross-section (
) and resonance integral(I
) were measured for the Cs(n,
)
Cs reaction by an activation method and mass spectrometry. We used Cs contained as an impurity in a normally available Cs standard solution. An isotope ratio of Cs and Cs in a standard Cs solution was measured by mass spectrometry to quantify Cs. The analyzed Cs samples were irradiated at the hydraulic conveyer of the research reactor in Institute for Integral Radiation and Nuclear Science, Kyoto University. Wires of Co/Al and Au/Al alloys were used as neutron monitors to measure thermal-neutron fluxes and epi-thermal Westcott's indices at an irradiation position. A gadolinium filter was used to measure the , and a value of 0.133 eV was taken as the cut-off energy. Gamma-ray spectroscopy was used to measure induced activities of Cs, Cs and monitor wires. On the basis of Westcott's convention, the and I values were derived as 8.57
0.25 barn, and 45.33.2 barn, respectively. The obtained in the present study agreed within the limits of uncertainties with the past reported value of 8.30.3 barn.
Ohgama, Kazuya; Ota, Hirokazu*; Oki, Shigeo; Iizuka, Masatoshi*
Proceedings of 2019 International Congress on Advances in Nuclear Power Plants (ICAPP 2019) (Internet), 9 Pages, 2019/05
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.
Maekawa, Fujio
Koenerugi Kasokuki Semina, OHO '18 Jukoyo Tekisuto, 11 Pages, 2018/09
no abstracts in English
Eguchi, Yuta; Sugawara, Takanori; Nishihara, Kenji; Tazawa, Yujiro; Tsujimoto, Kazufumi
Proceedings of 26th International Conference on Nuclear Engineering (ICONE-26) (Internet), 8 Pages, 2018/07
In order to investigate the basic neutronics characteristics of the accelerator-driven subcritical system (ADS), JAEA has a plan to construct a new critical assembly in the J-PARC project, Transmutation Physics Experimental Facility (TEF-P). This study aims to evaluate the natural cooling characteristics of TEF-P core which has large decay heat by minor actinide (MA) fuel, and to achieve a design that does not damage the core and the fuels during the failure of the core cooling system. In the evaluation of the TEF-P core temperature, empty rectangular lattice tube outer of the core has a significant effect on the heat transfer characteristics. The experiments by using the mockup device were performed to validate the heat transfer coefficient and experimental results were obtained. By using the obtained experimental results, the three-dimensional heat transfer analysis of TEF-P core were performed, and the maximum core temperature was obtained, 294
C. This result shows TEF-P core temperature would be less than 327C that the design criterion of temperature.
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.
Partitioning and Transmutation Technology Division, Nuclear Science and Engineering Center
JAEA-Technology 2017-033, 383 Pages, 2018/02
JAEA-Technology-2017-033.pdf:28.16MB
JAEA is pursuing research and development (R&D) on volume reduction and mitigation of degree of harmfulness of high-level radioactive waste. Construction of Transmutation Experimental Facility (TEF) is under planning as one of the second phase facilities in the Japan Proton Accelerator Complex (J-PARC) program to promote R&D on the transmutation technology with using accelerator driven systems (ADS). The TEF consists of two facilities: ADS Target Test Facility (TEF-T) and Transmutation Physics Experimental Facility (TEF-P). Development of spallation target technology and study on target materials are to be conducted in TEF-T with impinging a high intensity proton beam on a liquid lead-bismuth eutectic target. Whereas in TEF-P, by introducing a proton beam to minor actinide loaded cores, reactor physical properties of the cores are to be studied, and operation experiences of ADS are to be acquired. This report summarizes results of safety design for establishment permit of one of two TEF facilities, TEF-P.
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 
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.
Sugawara, Takanori; Katano, Ryota; Tsujimoto, Kazufumi
Annals of Nuclear Energy, 111, p.449 - 459, 2018/01
Times Cited Count：13 Percentile：79.66(Nuclear Science & Technology)This study aims to review the ADS design based on the outcome for the last dozen years and to investigate the impact of impurities in the transmutation cycle on the ADS neutronics design. The impact of impurities in the transmutation cycle is investigated for the reviewed reference design. For the uranium from the partitioning, the accompaniment of 20 wt.% U against the Pu weight is acceptable although the MA transmutation amount will be decreased slightly. For the rare earth (RE) from the partitioning, the accompaniment of 5 wt.% RE against the MA weight is allowable. In the reprocessing, the decontamination factor, DF=10 for RE is enough from the viewpoint of the neutronics design. The impact of the fuel composition accuracy is also investigated. The uncertainty of the ZrN ratio against the MA fuel should be less than 0.2% to minimize a surplus proton beam current due to the uncertainty.
Hayashi, Hirokazu; Sato, Takumi; Shibata, Hiroki; Tsubata, Yasuhiro
NEA/NSC/R(2017)3, p.427 - 432, 2017/11
Transmutation of long-lived radioactive nuclides including minor actinides (MA: Np, Am, Cm) has been studied in Japan Atomic Energy Agency (JAEA). Pb-Bi cooled sub-critical accelerator-driven system (ADS) is regarded as one of the powerful tools for transmutation of MA under the double strata fuel cycle concept. Uranium-free MA-Pu nitride fuel was chosen as the first candidate for MA transmutation. Reprocessing of spent ADS fuel and reusing MA recovered from the spent ADS fuels is necessary to improve the transmutation ratio. A pyrochemical process has been proposed as the first candidate for reprocessing of the spent nitride fuel for MA transmutation, because this technique has some advantages over aqueous process, such as the resistance to radiation damage, which is an important issue for the fuels containing large amounts of highly radioactive MA, and feasibility for recovering expensive N-15 in the spent fuels to be reused. This paper overviews the current status of the technology development, including our recent study. Development of the anode suitable for electro-refining of nitride fuels and that of the apparatus for renitridation of the metals recovered in Cd cathode for 100g-Cd scale cold tests are main topics. Evaluation of the batch sizes of each process, which is necessary for estimating the scale of the engineering-apparatus, with considering the decay heat of MA and FP, will also be introduced.
Iwamoto, Hiroki; Meigo, Shinichiro
EPJ Web of Conferences, 153, p.01016_1 - 01016_9, 2017/09
Times Cited Count：2 Percentile：78.04(Nuclear Science & Technology)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.
