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Zr + d reaction cross sections measured at 28 MeV/nucleonChillery, T.*; Hwang, J.*; Dozono, Masanori*; Imai, Nobuaki*; Michimasa, Shinichiro*; Sumikama, Toshiyuki*; Chiga, Nobuyuki*; Ota, Shinsuke*; Nakayama, Shinsuke; 49 of others*
Progress of Theoretical and Experimental Physics (Internet), 2023(12), p.121D01_1 - 121D01_11, 2023/12
Times Cited Count：0 Percentile：0.01(Physics, Multidisciplinary)The deuteron is a loosely bound system which can easily break up into its constituent proton and neutron whilst in the presence of Coulomb and nuclear fields. Previous experimental studies have shown that this breakup process has a significant impact on residual nucleus production from deuteron bombardment in the high energy range of 50 - 210 MeV/nucleon. However, there remains a lack of cross-section data at energies below 50 MeV/nucleon. The current study determined Zr + d reaction cross sections under inverse kinematics at approximately 28 MeV/nucleon using the BigRIPS separator, OEDO beamline, and SHARAQ spectrometer. Cross sections from this research were compared with previous measurements and theoretical calculations. The experimental results show a large enhancement of the production cross sections of residual nuclei, especially those produced from a small number of particle emissions, compared to the proton-induced reaction data at similar bombarding energy. The DEURACS calculation, which quantitatively takes deuteron-breakup effects into account, reproduces the data well. As a long-lived fission product, Zr remains a challenge for nuclear waste disposal and treatment. This study's low-energy data may assist future consideration of nuclear-waste treatment facilities, where Zr + d may feasibly transmute the waste into short-lived/stable nuclei.
Hayashi, Hirokazu; Tsubata, Yasuhiro; Sato, Takumi
Nihon Genshiryoku Gakkai Wabun Rombunshi (Internet), 22(3), p.97 - 107, 2023/08
The Japan Atomic Energy Agency has chosen nitride fuel as the first candidate for the transmutation of long-lived minor actinides (MA) using accelerator-driven systems (ADS). The pyrochemical method has been considered for reprocessing spent MA nitride fuels, because their decay heat should be very large for aqueous reprocessing. This study was conducted to investigate the effect of decay heat on the pyrochemical reprocessing of MA nitride fuels. On the basis of the estimated decay heats and the temperature limits of the materials that are to be handled in pyrochemical reprocessing, quantities adequate for handling in argon gas atmosphere were evaluated. From these considerations, we proposed that an electrorefiner with a diameter of 26 cm comprising 12 cadmium (Cd) cathodes with a diameter of 4 cm is suitable. On the basis of the size of the electrorefiner, the number necessary to reprocess spent MA fuels from 1 ADS in 200 days was evaluated to be 25. Furthermore, the amount of Cd-actinides (An) alloy to produce An nitrides by the nitridation-distillation combined reaction process was proposed to be about one-quarter that of Cd-An cathode material. The evaluated sizes and required numbers of equipment support the feasibility of pyrochemical reprocessing for MA nitride fuels.
Saito, Shigeru; Yamaguchi, Kazushi*; Yoshimoto, Hidemitsu*; Obayashi, Hironari; Sasa, Toshinobu
JAEA-Technology 2022-032, 51 Pages, 2023/03
JAEA-Technology-2022-032.pdf:4.51MB
In the Accelerator Driven System (ADS) being studied by the Japan Atomic Energy Agency (JAEA) for transmutation of long-lived radioactive waste, lead-bismuth eutectic alloy (LBE) is used as a spallation target and subcritical core coolant. A proton irradiation facility in J-PARC is considered to prepare a material irradiation database for ADS development. The proton irradiation facility is equipped with an LBE loop, which enables material irradiation tests in spallation environment under flowing LBE condition. The slow leakage of LBE is one of critical issue to use LBE safety. The slow leakage is caused by the biting slag and/or other materials at valve seal of drain valve. To solve this problem, JAEA examined the application of freeze-seal valve (FSV), which seal the piping by freezing LBE in specific position. Water-cooled and air-cooled freeze-seal valve test modules were fabricated, installed in the test section of the existing test stand for LBE technology development, and tested to confirm their operation and performance. As a result of the tests, it was confirmed that the water-cooled FSV test module worked well along to the design values. This report describes the outline and details of the test stand for LBE technology and each FSV test module, as well as the results of operation and performance verification tests.
Maekawa, Fujio
Ryoshi Bimu Kagaku No Kiso To Oyo; NSA/Commentaries, No.27, p.15 - 25, 2023/03
The nuclear transmutation technology that is one of the most beneficial industrial applications of quantum beams to humankind is explained.
(M = Gd, Np) by the reaction of MN with Pd and chlorination of MPd using cadmium chlorideHayashi, Hirokazu; Shibata, Hiroki; Sato, Takumi; Otobe, Haruyoshi
Journal of Radioanalytical and Nuclear Chemistry, 332(2), p.503 - 510, 2023/02
Times Cited Count：0 Percentile：0.01(Chemistry, Analytical)The formation of MPd (M = Gd, Np) by the reaction of MN with Pd at 1323 K in Ar gas flow was observed. Cubic AuCu
-type GdPd
(
= 0.4081 
0.0001 nm) and NpPd ( = 0.4081 0.0001 nm) were identified, respectively. The product obtained from the reaction of NpN with Pd contained additional phases including the hexagonal TiNi-type NpPd. Chlorination of the MPd (M = Gd, Np) samples was accomplished by the solid-state reaction using cadmium chloride at 673 K in a dynamic vacuum. Pd-rich solid solution phase saturated with Cd and an intermetallic compound PdCd were obtained as by-products of MCl formation.
Nakayama, Shinsuke; Furutachi, Naoya; Iwamoto, Osamu; Watanabe, Yukinobu*
NEA/NSC/R(2020)4 (Internet), p.345 - 349, 2022/10
Long-lived fission products (LLFPs) generated in nuclear reactors are strongly desired to be converted to stable or short-lived nuclides. Recently, it has been considered to transmute LLFPs by spallation reactions with high energy particles, and some experimental studies revealed that spallation reaction cross-sections induced by deuteron are larger than proton-induced ones. These results suggest the possibility that nuclear transmutation of LLFPs using deuteron beams is more efficient than one using proton beams. On the other hand, we have been developing a code system dedicated for deuteron-induced reactions, called DEURACS. DEURACS has been originally developed to contribute to the design of deuteron accelerator neutron sources. In the present study, we apply DEURACS to calculation of deuteron-induced spallation reactions on LLFPs. Through comparison with measured data, the applicability of DEURACS will be discussed.
Ohgama, Kazuya; Hara, Toshiharu*; Ota, Hirokazu*; Naganuma, Masayuki; Oki, Shigeo; Iizuka, Masatoshi*
Journal of Nuclear Science and Technology, 59(6), p.735 - 747, 2022/06
Times Cited Count：1 Percentile：31.61(Nuclear Science & Technology)Takei, Hayanori
Isotope News, (779), p.11 - 15, 2022/02
The Japan Atomic Energy Agency (JAEA) has designed a Transmutation Physics Experimental Facility (TEF-P) as an experimental facility in the Japan Proton Accelerator Research Complex (J-PARC). The TEF-P is a critical assembly driven by a low-power proton beam, a maximum of 10 W, which is extracted from a high-power beam source, such as 250 kW of 400 MeV proton beam of the J-PARC Linac. To extract such a low-power proton beam from the high-power proton beam, we developed a laser charge exchange (LCE) device and employed its technique, which is one of the non-contact beam extraction techniques. For the proof of performance of the LCE device to the TEF-P, a low-power proton beam was extracted using a negative-hydrogen Linac having an energy of 3 MeV, and a bright laser. This paper summarizes the experimental results.
Fukaya, Yuji; Ueta, Shohei; Yamamoto, Tomohiko; Chikazawa, Yoshitaka; Yan, X.
Nuclear Technology, 208(2), p.335 - 346, 2022/02
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)When the total volume control on toxicity for nuclear waste management is applied, it becomes a limiting factor for the permittable total operation capacity of nuclear reactors. An alternative conceptual scenario to achieve the control is proposed that aims at toxicity reduction through Partitioning and Transmutation (P&T). Specifically, the electricity generation capacity could be inversely increased up with transmutation of 
Sr-
Cs. Simultaneously, the cooling time before disposal is reduced to 50 years from the 300 years required by the existing scenarios such as (Accelerator Driven System (ADS). Finally, the scenario is also found feasible in terms of energy balance and cost by the neutron source of Li(d,xn) reaction with the deuteron accelerator for transmutation.
Murakami, Tsuyoshi*; Hayashi, Hirokazu
Journal of Nuclear Materials, 558, p.153330_1 - 153330_7, 2022/01
Times Cited Count：0 Percentile：0.01(Materials Science, Multidisciplinary)Excess amounts of dissolution agents, CdCl
and ZrCl
, are required to dissolve transuranium (TRU: Pu and minor actinides) nitrides into LiCl-KCl melts at the chemical dissolution step, which is the first step in the reprocessing of used nitride fuels. We propose an electrochemical process where the remaining Zr and Cd are recovered from the melts to be recycled as dissolution agents for the chemical dissolution step, leaving TRU in the melts. Since the initial concentration ratio of CdCl/ZrCl remaining in the melts would depend on the condition of the chemical dissolution step and would vary during the proposed electrochemical recovery process, electrochemical behaviors of Zr and Cd were investigated in LiCl-KCl melts with various concentration ratios of CdCl/ZrCl at 723 K to confirm the basic feasibility of the proposed process. Potentiostatic electrolysis was performed using a liquid Cd cathode at -1.05 V (vs. Ag/AgCl), which was a more positive potential than the redox potentials of TRU on the liquid Cd electrode. The obtained results showed that the current efficiency for recovering Zr and Cd from the melts was as high as 100% regardless of the CdCl/ZrCl concentration ratio in the melts.
Ogata, Takanari*; Takano, Masahide
Nihon Genshiryoku Gakkai-Shi ATOMO
, 63(7), p.541 - 546, 2021/07
This is a commentary on metallic fuels for fast reactors and nitride fuels for minor actinide transmutation in accelerator driven system, as the 4th article of serial lecture on Journal of the Atomic Energy Society of Japan; Concepts and basic designs of various nuclear fuels.
Takei, Hayanori; Tsutsumi, Kazuyoshi*; Meigo, Shinichiro
Journal of Nuclear Science and Technology, 58(5), p.588 - 603, 2021/05
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)The Japan Atomic Energy Agency (JAEA) has designed a Transmutation Physics Experimental Facility (TEF-P) as an experimental facility in the Japan Proton Accelerator Research Complex (J-PARC). The TEF-P is a critical assembly driven by a low-power proton beam, a maximum of 10 W, which is extracted from a high-power beam source, such as 250 kW of 400 MeV proton beam of the J-PARC Linac. To extract such a low-power proton beam from the high-power proton beam, we developed a laser charge exchange (LCE) device and employed its technique, which is one of the non-contact beam extraction techniques. For the proof of performance of the LCE device to the TEF-P, a low-power proton beam was extracted using a negative-hydrogen (H
) Linac having an energy of 3 MeV, and a bright continuous laser. Proton beam with the power of 0.57 mW was successfully extracted with a laser stripping efficiency of 
. These experimental values are in good agreement with the estimated ones.
Iwasa, Toma; Takano, Masahide
JAEA-Technology 2020-024, 29 Pages, 2021/03
JAEA-Technology-2020-024.pdf:2.33MB
Partitioning and transmutation of minor actinides (MA) is an important issue to reduce volume and radio-toxicity of high-level radioactive wastes. In Nuclear Science Research Institute, we have been carrying out R&D on MA-bearing nitride fuel for accelerator driven system. In the actual nitride fuel fabrication process, a special nitrogen gas highly enriched with 
N is required to avoid 
C production from N by (n,p) reaction in the fuel. For the economical use of such expensive gas, we need a nitrogen circulation refining system that can remove carbon monoxide (CO) evolved by carbothermic nitridation of oxides and can use the nitrogen gas in the closed system without loss. To develop the system, at first we listed up the performance requirements, and then designed and assembled a prototype system for laboratory-scale demonstration. The system consists of CO removal unit and circulation unit that can automatically keep the system pressure and the gas flow rate constant. As a result of demonstration on the nitridation of oxide, both units completely satisfy the requirements. We confirmed that the concept can be applied to the actual fuel fabrication with further additional function such as automatic hydrogen feed for the control of decarburization.
N isotopic enrichment plant and its cost for nitride fuel fabrication (Contract research)Takano, Masahide
JAEA-Review 2020-080, 24 Pages, 2021/03
JAEA-Review-2020-080.pdf:1.71MB
Nitride is one of the potential fuel forms for minor actinide transmutation by the accelerator driven system. However, to avoid the C production from N by (n, p) reaction in the fuel, the special N
gas highly enriched with N is needed for the fuel fabrication. To realize the availability of such gas has been an important issue. In this report, the degree of N enrichment and gas amount required for the fuel fabrication are shown first, and then among the existing isotopic enrichment methods, N cryogenic distillation is found to be a promising method from the viewpoint of constructing a huge scale plant because of its non-hazardous feature. Some commercial plants for 
O enrichment based on the similar method have already been operated in Japan. Its technology and components can be applied to the N enrichment plant. Assuming the supply of N gas from a cryogenic distillation plant, a series of enrichment simulation is performed to evaluate the plant size as functions of targeted degree of enrichment and annual production. By using the simulation results, the basic specifications for plant components and equipment are designed. As a result, a huge plant for annual production of 1000 kg N gas with 99% enrichment is found to be technically feasible. The N gas production cost is also evaluated to be approximately 1/30 of the current distribution price. This survey shows the availability of N gas required for the nitride fuel fabrication in both technical and economic aspects.
Nakayama, Shinsuke; Iwamoto, Osamu; Watanabe, Yukinobu*
EPJ Web of Conferences, 239, p.03014_1 - 03014_4, 2020/09
Times Cited Count：2 Percentile：86.93(Nuclear Science & Technology)Intensive neutron sources using deuteron accelerators have been proposed for various applications such as irradiation test for fusion reactor materials and production of radioisotopes for medical use. In addition, transmutation system using deuteron-induced spallation reactions has been recently proposed for LLFPs. Accurate and comprehensive deuteron nuclear data are indispensable in the design study of such facilities. Under the above situations, we have been developing a code system dedicated for deuteron-induced reactions, which is called DEURACS. In the present work, calculations using DEURACS are compared with available experimental data up to 200 MeV such as DDXs for emission of neutron or light charged particles. We also analyze isotopic production cross sections of residual nuclei. Validation of the present modelling in DEURACS is discussed through comparison with the experimental data.
Nakamura, Satoshi; Kimura, Takahiro; Ban, Yasutoshi; Tsubata, Yasuhiro; Matsumura, Tatsuro
JAEA-Technology 2020-009, 22 Pages, 2020/08
JAEA-Technology-2020-009.pdf:2.92MB
Partitioning and transmutation technology division is planning to measure fission rate ratios that contribute to validate nuclear data of minor actinides (MA). For this purpose, MA sources for fission chambers were prepared using electrodeposition method. The radioactivity of each MA source was quantified, and its uncertainty was evaluated. Seven types of MA sources with different radioactivity were prepared using four nuclides of 
Np, 
Am, 
Am, and 
Cm. A Cm source solution of which radioactivity was quantified by isotope dilution method was used to prepare working standard sources of Cm. The radioactivities were quantified as 1461 Bq, 2179 Bq, and 2938 Bq for Np sources, 1.428 MBq for Am source, 370.5 kBq and 89.57 kBq for Am sources, and 2.327 MBq for Cm source with, the uncertainty of 0.35% (1
). This report summarizes the method for preparation and quantification of MA sources, and uncertainty evaluation.
Takei, Hayanori; Hirano, Koichiro; Meigo, Shinichiro; Tsutsumi, Kazuyoshi*
Proceedings of 8th International Beam Instrumentation Conference (IBIC 2019) (Internet), p.595 - 599, 2020/06
Japan Proton Accelerator Research Complex (J-PARC) has a plan to build the Transmutation Physics Experimental Facility (TEF-P), in which a 400-MeV proton beam will be delivered from negative hydrogen (H) accelerated by the linac. Since the TEF-P requires a stable proton beam with a power of less than 10 W, a steady and meticulous beam extraction method is required to extract a small amount of the proton beam from the high power beam using 250 kW. To fulfill this requirement, we have developed beam extraction based on the Laser Charge Exchange (LCE) method. For the demonstration present beam extraction technique, an experiment was conducted using H beam accelerated by the 3-MeV linac at RFQ test-stand in J-PARC. As a result of the experiment with continuous wave (CW) of the Laser, a charge-exchanged long-pulsed H
beam with a power of about 0.70 W equivalent was successfully obtained under the TEF-P beam condition.
Wang, H.*; Otsu, Hideaki*; Chiga, Nobuyuki*; Kawase, Shoichiro*; Takeuchi, Satoshi*; Sumikama, Toshiyuki*; Koyama, Shumpei*; Sakurai, Hiroyoshi*; Watanabe, Yukinobu*; Nakayama, Shinsuke; et al.
Communications Physics (Internet), 2(1), p.78_1 - 78_6, 2019/07
Times Cited Count：8 Percentile：56.2(Physics, Multidisciplinary)Searching for effective pathways for the production of proton- and neutron-rich isotopes through an optimal combination of reaction mechanism and energy is one of the main driving forces behind experimental and theoretical nuclear reaction studies as well as for practical applications in nuclear transmutation of radioactive waste. We report on a study on incomplete fusion induced by deuteron, which contains one proton and one neutron with a weak binding energy and is easily broken up. This reaction study was achieved by measuring directly the cross sections for both proton and deuteron for 
Pd at 50 MeV/u via inverse kinematics technique. The results provide direct experimental evidence for the onset of a cross-section enhancement at high energy, indicating the potential of incomplete fusion induced by loosely-bound nuclei for creating proton-rich isotopes and nuclear transmutation of radioactive waste.
Nishihara, Kenji
ImPACT Fujita Puroguramu Kokai Seika Hokokukai "Kaku Henkan Niyoru Koreberu Hoshasei Haikibutsu No Ohaba Na Teigen, Shigenka" Seika Hokokusho, Shiryoshu, p.28 - 31, 2019/03
In this project, long-lived fission products (LLFP) contained in conventional high-level radioactive wastes are separated and their life is reduced, and elements that can be used as resources are separated. By shortening the life of LLFP, it has been shown that it may be possible to dispose in intermediate depth of several tens of meters, meeting safety requirements, instead of geological disposal. In addition, for reassuring recycling of usable elements, possible exposure pathways were evaluated to estimate the safe concentration level of radioactivity.
Nishihara, Kenji
ImPACT Fujita Puroguramu Kokai Seika Hokokukai "Kaku Henkan Niyoru Koreberu Hoshasei Haikibutsu No Ohaba Na Teigen, Shigenka" Seika Hokokusho, Shiryoshu, p.130 - 133, 2019/03
High level radioactive waste contains elements with various characteristics. It is possible to reduce the load on the disposal site by separating them according to those characteristics and appropriately dealing with them. In this project, we are working to shorten the life span of long-lived fission products (LLFP). When this technology is realized, high-level radioactive wastes will become new radioactive wastes with low radioactivity. As a result of investigation of disposal concept of new radioactive waste, it turned out that intermediate-depth disposal currently considered for low level radioactive waste may be suitable. Intermediate-depth disposal is a method of small-scale disposal in shallow locations as compared to geological disposal for conventional high-level radioactive waste. We conducted a safety assessment when this disposal is applied to new radioactive wastes, and found that it is possible to safely dispose of for the four LLFPs addressed by this project.
