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Journal Articles

Improved bunching and longitudinal emittance control in an RFQ

Jameson, R. A.*; Yee-Rendon, B.

Journal of Instrumentation (Internet), 17(12), p.P12011_1 - P12011_11, 2022/12

 Times Cited Count:0

A new application of vane modulation variation in a Radio Frequency Quadrupole (RFQ) cell has been applied that significantly improves beam bunching and longitudinal emittance control to achieve lower longitudinal rms emittance at the RFQ output. This procedure occurs in the individual cells, is independent of the overall design, and therefore is general, affording an extra parameter for beam manipulation. It can be applied besides the usual goals of vane modulation variation, e.g., to achieve higher acceleration efficiency. Examples of the cumulative effects on the overall design are provided to point out further exploration avenues for the designer.

Journal Articles

A Plan of Proton Irradiation Facility at J-PARC and possibilities of application to nuclear data research

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.

Journal Articles

Measurement of 107-MeV proton-induced double-differential neutron yields for iron for research and development of accelerator-driven systems

Iwamoto, Hiroki; Nakano, Keita; Meigo, Shinichiro; Satoh, Daiki; Iwamoto, Yosuke; Ishi, Yoshihiro*; Uesugi, Tomonori*; Kuriyama, Yasutoshi*; Yashima, Hiroshi*; Nishio, Katsuhisa; et al.

JAEA-Conf 2022-001, p.129 - 133, 2022/11

For accurate prediction of neutronic characteristics for accelerator-driven systems (ADS) and a source term of spallation neutrons for reactor physics experiments for the ADS at Kyoto University Critical Assembly (KUCA), we have launched an experimental program to measure nuclear data on ADS using the Fixed Field Alternating Gradient (FFAG) accelerator at Kyoto University. As part of this program, the proton-induced double-differential thick-target neutron-yields (TTNYs) and cross-sections (DDXs) for iron have been measured with the time-of-flight (TOF) method. For each measurement, the target was installed in a vacuum chamber on the beamline and bombarded with 107-MeV proton beams accelerated from the FFAG accelerator. Neutrons produced from the targets were detected with stacked, small-sized neutron detectors composed of the NE213 liquid organic scintillators and photomultiplier tubes, which were connected to a multi-channel digitizer mounted with a field-programmable gate array (FPGA), for several angles from the incident beam direction. The TOF spectra were obtained from the detected signals and the FFAG kicker magnet's logic signals, where gamma-ray events were eliminated by pulse shape discrimination applying the gate integration method to the FPGA. Finally, the TTNYs and DDXs were obtained from the TOF spectra by relativistic kinematics.

Journal Articles

Beam physics design of a 30-MW beam transport to the target for an accelerator-driven subcritical system

Yee-Rendon, B.; Meigo, Shinichiro; Kondo, Yasuhiro; Tamura, Jun; Nakano, Keita; Maekawa, Fujio; Iwamoto, Hiroki; Sugawara, Takanori; Nishihara, Kenji

Journal of Instrumentation (Internet), 17(10), p.P10005_1 - P10005_21, 2022/10

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

To reduce the hazard of minor actinides in nuclear waste, JAEA proposed an accelerator-driven subcritical system (JAEA-ADS). The JAEA-ADS drives a subcritical reactor 800-MWth by 30-MW proton linac delivering the beam to the spallation neutron target inside the reactor. The beam transport to the target (BTT) is required for high-beam power stability and low peak density to ensure the integrity of the beam window. Additionally, the design should have compatible with the reactor design for the maintenance and replacement of the fuel and the beam window. A robust-compact BTT design was developed through massive multiparticle simulations. The beam optics was optimized to guarantee beam window feasibility requirements by providing a low peak density of less than 0.3 $$mu$$A/mm$$^2$$. Beam stability was evaluated and improved by simultaneously applying the linac's input beam and element errors. The input beam errors to the reactor were based on the beam degradation obtained by implementing fast fault compensation in the linac. Those results show that the BTT fulfills the requirements for JAEA-ADS.

Journal Articles

Sensitivity coefficient evaluation of an accelerator-driven system using ROM-Lasso method

Katano, Ryota; Yamamoto, Akio*; Endo, Tomohiro*

Nuclear Science and Engineering, 196(10), p.1194 - 1208, 2022/10

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

In this study, we propose the ROM-Lasso method that enables efficient evaluation of sensitivity coefficients of neutronics parameters to cross-sections. In the proposed method, a vector of sensitivity coefficients is expanded by subspace bases, so-called Active Subspace (AS) based on the idea of Reduced Order Modeling (ROM). Then, the expansion coefficients are evaluated by the Lasso linear regression between cross-sections and neutronics parameters obtained by the random sampling. The proposed method can be applied in the case where the adjoint method is difficult to be applied since the proposed method uses only forward calculations. In addition, AS is an effective subspace that can expand the vector of sensitivity coefficients with the lower number of dimension. Thus, the number of unknows is reduced from the original number of input parameters and the calculation cost is dramatically improved compared to the Lasso regression without AS. In this paper, we conducted ADS burnup calculations as a verification. We have shown how AS bases are obtained and the applicability of the proposed method.

Journal Articles

Overview of ADS projects in the world

Yee-Rendon, B.

Proceedings of 31st International Linear Accelerator Conference (LINAC 2022) (Internet), p.310 - 313, 2022/10

Accelerator-driven subcritical systems (ADS) offer an advantageous option for the transmutation of nuclear waste. ADS employs high-intensity proton linear accelerators (linacs) to produce spallation neutrons for a subcritical reactor. Besides the challenges of any megawatt proton machine, ADS accelerator must operate with stringent reliability to avoid thermal stress in the reactor structures. Thus, ADS linacs have adopted a reliability-oriented design to satisfy the operation requirements. This work provides a review and the present status of the ADS linacs in the world.

Journal Articles

Development of a miniature electromagnet probe for the measurement of local velocity in heavy liquid metals

Ariyoshi, Gen; Obayashi, Hironari; Sasa, Toshinobu

Journal of Nuclear Science and Technology, 59(9), p.1071 - 1088, 2022/09

 Times Cited Count:1 Percentile:71.47(Nuclear Science & Technology)

Electromagnetic induction method is one of the effective techniques for local velocity measurement in heavy liquid metals. Ricou and Vives' probe and Von Weissenfluh's probe are famous instrumentations using a permanent magnet. However, sensitivity and measurement volume of the probes show unexpected variation since demagnetization of the magnet is occurred by temperature increase up to the Curie temperature. In this study, electromagnetic probe incorporating a miniature electromagnet was newly developed to overcome such unexpected variation. The diameter and the length of the sensor was 6 mm and 155 mm, respectively. The sensitivity and the measurement volume of the probe were assessed by measurement of local velocity of flowing mercury in a square channel. To clarify the validity for the measured velocity profiles, numerical velocity profiles were calculated and compared with experiment. And the validity for the measured velocity profiles were confirmed by calculated result.

Journal Articles

Beam dynamics studies for fast beam trip recovery of the Japan Atomic Energy Agency accelerator-driven subcritical system

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

Physical Review Accelerators and Beams (Internet), 25(8), p.080101_1 - 080101_17, 2022/08

 Times Cited Count:1 Percentile:67.14(Physics, Nuclear)

High reliability and availability are primary goals for the operation of particle accelerators, especially for accelerator-driven subcritical systems (ADS). ADSs employ high-power beams for the transmutation of minor actinide; as a result, the amount and the radiotoxicity of the nuclear waste are considerably reduced. To this end, the Japan Atomic Energy Agency is designing a 30-MW continuous wave (cw) super-conducting proton linear accelerator (linac) that supplies neutrons to an 800-MW subcritical reactor by a spallation process. The major challenge for an ADS linac is the strict control of the beam trip duration and its frequency to avoid thermal stress in the subcritical reactor structures. The maximum allowed beam trips for failures longer than a few seconds are estimated to be far below the rate achieved in current accelerators. Thus, we implemented a combination of hot standby and local compensation that enables a fast beam recovery. This work comprehensively investigated the tolerance of our linac lattice for the local compensations for failures in superconducting cavities and magnets. This scheme includes simultaneous compensation of multiple cavities in independent and same cryomodules that significantly enhance the reliability of the linac. The returned schemes present acceptable beam performance to guarantee the integrity of the linac and the beam transport to the target; moreover, they satisfy the beam stability in the beam window. In addition, the readjusted elements are subjected to moderate stress to ensure a sustainable operation. This manuscript reports the beam dynamics results toward fulfilling the high reliability demanded by an ADS linac.

Journal Articles

Novel $$^{90}$$Sr analysis of environmental samples by ion-laser interaction mass spectrometry

Honda, Maki; Martschini, M.*; Marchhart, O.*; Priller, A.*; Steier, P.*; Golser, R.*; Sato, Tetsuya; Tsukada, Kazuaki; Sakaguchi, Aya*

Analytical Methods, 14(28), p.2732 - 2738, 2022/07

 Times Cited Count:1 Percentile:67.54(Chemistry, Analytical)

The sensitive $$^{90}$$Sr analysis with accelerator mass spectrometry (AMS) was developed for the advances of environmental radiology. One advantage of AMS is the ability to analyze various environmental samples with $$^{90}$$Sr/$$^{88}$$Sr atomic ratios of 10$$^{-14}$$ in a simple chemical separation. Three different IAEA samples with known $$^{90}$$Sr concentrations (moss-soil, animal bone, Syrian soil: 1 g each) were analyzed to assess the validity of the chemical separation and the AMS measurement. The $$^{90}$$Sr measurements were conducted on the AMS system combined with the Ion Laser InterAction MasSpectrometry (ILIAMS) setup at the University of Vienna, which has excellent isobaric separation performance. The isobaric interference of $$^{90}$$Zr in the $$^{90}$$Sr AMS was first removed by chemical separation. The separation factor of Zr in two-step column chromatography with Sr resin and anion exchange resin was 10$$^{6}$$. The $$^{90}$$Zr remaining in the sample was removed by ILIAMS effectively. This simple chemical separation achieved a limit of detection $$<$$ 0.1 mBq in the $$^{90}$$Sr AMS, which is lower than typical $$beta$$-ray detection. The agreement between AMS measurements and nominal values for the $$^{90}$$Sr concentrations of IAEA samples indicated that the new highly-sensitive $$^{90}$$Sr analysis in the environmental samples with AMS is reliable even for high matrix samples of soil and bone.

Journal Articles

R&D on Accelerator Driven Nuclear Transmutation System (ADS) at J-PARC, 1; Accelerator Driven Nuclear Transmutation System (ADS)

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.

Journal Articles

R&D on Accelerator Driven Nuclear Transmutation System (ADS) at J-PARC, 2; Transmutation Experimental Facility at J-PARC

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.

Journal Articles

R&D on Accelerator Driven Nuclear Transmutation System (ADS) at J-PARC, 3; Lead-bismuth target technology

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.

Journal Articles

R&D on Accelerator Driven Nuclear Transmutation System (ADS) at J-PARC, 4; Proton beam technology and neutronics

Meigo, Shinichiro; Nakano, Keita; Iwamoto, Hiroki

Purazuma, Kaku Yugo Gakkai-Shi, 98(5), p.216 - 221, 2022/05

For the realization of accelerator-driven transmutation systems (ADS) and the construction of the ADS target test facility (TEF-T) at J-PARC, it is necessary to study the proton beam handling technology and neutronics for protons in the GeV energy region. Accordingly, the Nuclear Transmutation Division of J-PARC has studied these issues with using J-PARC's accelerator facilities, and so on. This paper introduces these topics.

Journal Articles

R&D on Accelerator Driven Nuclear Transmutation System (ADS) at J-PARC, 5; Research and developments of a superconducting linac for ADS

Kondo, Yasuhiro; Takei, Hayanori; Yee-Rendon, B.; Tamura, Jun

Purazuma, Kaku Yugo Gakkai-Shi, 98(5), p.222 - 226, 2022/05

A superconducting accelerating cavity is indispensable to realize a driver linac that meets the requirements of ADS. The low-energy section of the accelerators, which is normal conducting one, was redesigned to reflect the recent progress in the development of superconducting accelerator cavities. In addition, we are developing a prototype cavity for the spoke-type cavity that has not been developed well. This section reports on the latest research and development of ADS linacs at the Japan Atomic Energy Agency.

Journal Articles

Estimated isotopic compositions of Yb in enriched $$^{176}$$Yb for producing $$^{177}$$Lu with high radionuclide purity by $$^{176}$$Yb($$d,x$$)$$^{177}$$Lu

Nagai, Yasuki*; Kawabata, Masako*; Hashimoto, Shintaro; Tsukada, Kazuaki; Hashimoto, Kazuyuki*; Motoishi, Shoji*; Saeki, Hideya*; Motomura, Arata*; Minato, Futoshi; Ito, Masatoshi*

Journal of the Physical Society of Japan, 91(4), p.044201_1 - 044201_10, 2022/04

 Times Cited Count:0 Percentile:0(Physics, Multidisciplinary)

Recently, $$^{177}$$Lu is considered as one of the most important medical RIs for treating neuroendocrine tumors. A plan to produce $$^{177}$$Lu with high purity by using enriched $$^{176}$$Yb samples with irradiation of deuteron beams in accelerators has been discussed. However, since the other Yb isotopes contained in the Yb sample interacts with deuterons, Lu isotopes other than $$^{177}$$Lu are produced as impurities. Since the purity of $$^{177}$$Lu is important for medical use, a method to evaluate the impurity of Lu has been required. In this study, we proposed a new method to estimate production yields of each Lu isotopes in Yb samples with arbitrary isotopic compositions by using excitation functions of Yb($$d,x$$)Lu reactions and the particle transport calculation code PHITS. The method plays an important role in discussing the isotopic composition of enriched samples to produce high-purity $$^{177}$$Lu using accelerators.

JAEA Reports

Development of mock-up test loop (IMMORTAL) for LBE spallation target

Obayashi, Hironari; Yamaki, Kenichi*; Yoshimoto, Hidemitsu*; Kita, Satoshi*; Wan, T.*; Sasa, Toshinobu

JAEA-Technology 2021-035, 66 Pages, 2022/03

JAEA-Technology-2021-035.pdf:4.26MB

Construction of Transmutation Experimental Facility (TEF) is under planning in Japan Proton Accelerator Research Complex (J-PARC) program to promote R&Ds on realization of transmutation technology by an accelerator driven system (ADS). As a facility of TEF, ADS Target Test Facility (TEF-T) will provide a spallation target to study target technology and perform post irradiation examination (PIE) of candidate materials of ADS. In ADS, lead-bismuth eutectic (LBE) alloy is used as a spallation target material and a core coolant. As is well known, LBE has corrosive to structural materials hence each component of the target system should provide compatibility with LBE. In addition, instrumentations for LBE are restricted by the target operation condition such as high temperature and irradiation environment. The devices for LBE have been developed individually to achieve the LBE target system. "Integrated Multi-functional MOckup for TEF-T Real-scale TArget Loop, IMMORTAL" was fabricated as a mock-up test loop of the target for the purpose of the integration testing of individually developed devices. This report describes an overview of IMMORTAL and the design of the installed devices.

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

JAEA-Research-2021-018.pdf:2.93MB

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, $$^{206}$$Bi 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$$^3$$.

JAEA Reports

Measurement of nuclide production cross-sections in high-energy proton-induced spallation reactions at J-PARC

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 $$^9$$Be, C, $$^{27}$$Al, $$^{45}$$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.

Journal Articles

Developing accelerator mass spectrometry capabilities for anthropogenic radionuclide analysis to extend the set of oceanographic tracers

Hain, K.*; Martschini, M.*; G$"u$lce, F.*; Honda, Maki; Lachner, J.*; Kern, M.*; Pitters, J.*; Quinto, F.*; Sakaguchi, Aya*; Steier, P.*; et al.

Frontiers in Marine Science (Internet), 9, p.837515_1 - 837515_17, 2022/03

 Times Cited Count:6 Percentile:98.89(Environmental Sciences)

Recent major advances in accelerator mass spectrometry (AMS) at the Vienna Environmental Research Accelerator (VERA) regarding detection efficiency and isobar suppression have opened possibilities for the analysis of additional long-lived radionuclides at ultra-low environmental concentrations. These radionuclides, including $$^{233}$$U, $$^{135}$$Cs, $$^{99}$$Tc and $$^{90}$$Sr, will become important for oceanographic tracer application due to their generally conservative behavior in ocean water. In particular, the isotope ratios $$^{233}$$U/$$^{236}$$U and $$^{137}$$Cs/$$^{135}$$Cs have proven to be powerful fingerprints for emission source identification as they are not affected by elemental fractionation. Improved detection efficiencies allowed us to analyze all major long-lived actinides, i.e. $$^{236}$$U, $$^{237}$$Np, $$^{239, 240}$$Pu, $$^{241}$$Am as well as the very rare $$^{233}$$U, in the same 10 L water samples of an exemplary depth profile from the northwest Pacific Ocean. Especially for $$^{90}$$Sr analysis, our new approach has already been validated for selected reference materials (e.g. IAEA-A-12) and is ready for application in oceanographic studies. We estimate that a sample volume of only (1-3) L ocean water is sufficient for $$^{90}$$Sr as well as $$^{135}$$Cs analysis, respectively.

Journal Articles

Subcriticality determination methodology during fuel loading of accelerator-driven system

Katano, Ryota

Journal of Nuclear Science and Technology, 59(3), p.368 - 381, 2022/03

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

We propose a subcriticality determination methodology to be applied during fuel loading of an accelerator-driven system (ADS). In this methodology, subcriticality is determined via the area ratio method (via the proton accelerator) in the first step and by the neutron source multiplication method (through the spontaneous fission neutrons of minor actinides) in subsequent steps; then, the number of fuel assemblies to be loaded in the next step is predicted. We performed a numerical simulation of the proposed methodology, and the estimated subcriticalities agreed well with those obtained by eigenvalue calculations. We also conducted an uncertainty assessment of the proposed methodology and deduced a value of 1000 pcm for the $$k_{eff}$$ uncertainty. The proposed methodology can be a candidate for practical subcriticality monitoring for ADS.

367 (Records 1-20 displayed on this page)