Development of safety design technologies for sodium-cooled fast reactor coupled to thermal energy storage system with sodium-molten salt heat exchanger

Yamano, Hidemasa; Kurisaka, Kenichi; Takano, Kazuya; Kikuchi, Shin; Kondo, Toshiki; Umeda, Ryota; Shirakura, Shota*; Hayashi, Masaaki*

Proceedings of 8th International Conference on New Energy and Future Energy Systems (NEFES 2023) (Internet), p.27 - 34, 2023/00

https://doi.org/10.3233/ATDE231072

This project studies investigation on safety design guideline and risk assessment technology for sodium-cooled fast reactor with the molten-salt heat storage system, development of evaluation method for heat transferring performance between sodium and molten-salt and improvement of the performance, and evaluation of chemical reaction characteristic between sodium and molten-salt and improvement of its safety. The project overview is presented in this report.

Determination of site occupancy of boron in 6H-SiC by multiple-wavelength neutron holography

Hayashi, Koichi*; Lederer, M.*; Fukumoto, Yohei*; Goto, Masashi*; Yamamoto, Yuta*; Happo, Naohisa*; Harada, Masahide; Inamura, Yasuhiro; Oikawa, Kenichi; Oyama, Kenji*; et al.

Applied Physics Letters, 120(13), p.132101_1 - 132101_6, 2022/03

https://doi.org/10.1063/5.0080895

Behavior of Sm in the boron cage of Sm-doped B ( =Yb, La) observed by multiple-wavelength neutron holography

Uechi, Shoichi*; Oyama, Kenji*; Fukumoto, Yohei*; Kanazawa, Yuki*; Happo, Naohisa*; Harada, Masahide; Inamura, Yasuhiro; Oikawa, Kenichi; Matsuhra, Wataru*; Iga, Fumitoshi*; et al.

Physical Review B, 102(5), p.054104_1 - 054104_10, 2020/08

https://doi.org/10.1103/PhysRevB.102.054104

Comparison between Monte Carlo simulation and measurement with a 3D polymer gel dosimeter for dose distributions in biological samples

Furuta, Takuya; Maeyama, Takuya*; Ishikawa, Kenichi*; Fukunishi, Nobuhisa*; Fukasaku, Kazuaki*; Takagi, Shu*; Noda, Shigeho*; Himeno, Ryutaro*; Hayashi, Shinichiro*

Physics in Medicine & Biology, 60(16), p.6531 - 6546, 2015/08

https://doi.org/10.1088/0031-9155/60/16/6531

Low reproducibility of dose distribution in inhomogeneous regions such as soft matter near bones is known with the simple dose analysis currently adopted in treatment planning of particle cancer therapy. Therefore a treatment planning system based on Monte Carlo simulation having better accuracy is highly desired. In order to assess the simulation accuracy of a Monte Carlo simulation code in situations closely related to medical application, we performed a comparison of dose distribution in a biological sample obtained by experiment and that by simulation. In particular, we irradiate a carbon beam on a biological sample composed of fresh chicken meat and bones, with a PAGAT gel dosimeter placed behind it, and compare the complex dose distribution in the gel dosimeter created by the beam passing through the inhomogeneous sample. Monte Carlo simulation using PHITS code was conducted by reconstructing the biological sample from its computed tomography images. The simulation accurately reproduced the experimental distal edge structure of the dose distribution with an accuracy under about 2 mm.

Beam position monitor system of J-PARC RCS

Hayashi, Naoki; Kawase, Masato; Hatakeyama, Shuichiro; Hiroki, Seiji; Saeki, Riuji; Takahashi, Hiroki; Teruyama, Yuzo*; Toyokawa, Ryoji*; Arakawa, Dai*; Hiramatsu, Shigenori*; et al.

Nuclear Instruments and Methods in Physics Research A, 677, p.94 - 106, 2012/06

https://doi.org/10.1016/j.nima.2012.02.013

A beam position monitor (BPM) system at J-PARC RCS is described. The J-PARC RCS is a rapid-cycling proton synchrotron and its designed beam power is 1 MW. A diameter of the BPM detector is larger than 250 mm, however the system has to measure the beam position very accurately. The system should work not only for the high intensity but also for lower intensity. There are 54 BPM around the ring and most of them are placed inside steering magnets because of quite limited space. The BPM detector is an electro static type and it has four electrodes, and a pair of electrode gives a good linear response with diagonal cut shape to detect the charge center precisely. The signal processing unit, which is equipped with 14-bit 40 MSPS ADC and 600 MHz DSP, has been developed. They are controlled via shared memory space and EPICS. It is capable to record full 25 Hz pulse data for averaged mode and it could also store whole waveform data for further analysis, like turn-by-turn position calculation.

Upgrade of the transport monitoring system of nuclear materials

Uchida, Shinichi; Yuasa, Wataru; Hayashi, Akihiko; Inose, Shoichi; Ouchi, Yuichiro; Asakawa, Kenichi*; Uchikoshi, Yuta*

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-32-Kai Nenji Taikai Rombunshu (Internet), 7 Pages, 2011/11

JAEA has developed a TMS which can monitor the movement of nuclear material convoys to make safe and proper transport of nuclear materials. The TMS mainly consists of the location information monitoring system to monitor the location of the convoys and the visual information monitoring system to survey around the convoys. The TMS can send information in real-time to the TCC located at the shipper site. The JAEA has operated the TMS for ground transportation of MOX fuels since 2005, and the JAEA solved visual control problems that were observed during the operational experience and upgraded the system by adding the automatic communication control system, etc. In the case of emergency during transport, the TMS can send much more detailed visual information of the accident site to the TCC, which is useful for planning and executing an effective response. This paper reports the overview of the upgraded TMS and its effectiveness.

Online monitoring of the H0 dump beam current during user operation of J-PARC RCS

Hatakeyama, Shuichiro; Saha, P. K.; Yoshimoto, Masahiro; Yamamoto, Kazami; Hayashi, Naoki; Sato, Kenichiro*

Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.1013 - 1015, 2010/08

http://www.pasj.jp/web_publish/pasj7/proceedings/P_5PM/P_EH_5PM/THPS076.pdf

In J-PARC (Japan Proton Accelerator Research Complex), the negative hydrogen ions (H) accelerated by LINAC are converted to protons (H) by the Charge Stripping Foil before injecting into RCS (Rapid Cycling Synchrotron). About 99.7% of H are stripped it's two electrons by the 1st foil. The rest of H0 and H are converted to H by 2nd and 3rd foils and abandoned into H0 dump. Monitoring of the fraction of beam current into the H0 dump gives useful information for the stable beam supply during accelerator user's operation. This report describes the method of online monitoring to estimate the beam current of the H0 dump line.

Shot-by-shot beam position monitor system for beam transport line from RCS to MR in J-PARC

Tejima, Masaki*; Arakawa, Dai*; Hashimoto, Yoshinori*; Sato, Kenichiro*; Toyama, Takeshi*; Yamamoto, Noboru*; Hayashi, Naoki; Hanamura, Kotoku*

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.978 - 980, 2010/05

http://accelconf.web.cern.ch/AccelConf/IPAC10/papers/mope011.pdf

To maintain the beam orbit of beam transport line from RCS to MR in J-PARC (3-50BT), 14 beam position monitors (BPMs) were installed. Their signals gathered in the local control building (D01) have been measured by using 14 digitizing oscilloscopes. The data acquisition system have a performance of shot-by-shot measurement.

Estimation of secondary electron effect in the J-PARC Rapid cycling synchrotron after first study

Yamamoto, Kazami; Kamiya, Junichiro; Ogiwara, Norio; Kinsho, Michikazu; Hayashi, Naoki; Saeki, Riuji; Sato, Kenichiro*; Toyama, Takeshi*

Applied Surface Science, 256(4), p.958 - 961, 2009/11

https://doi.org/10.1016/j.apsusc.2009.05.137

The Japan Proton Accelerator Research Complex (J-PARC) project is a joint project of Japan Atomic Energy Agency (JAEA) and High Energy Accelerator Research Organization (KEK). The accelerator complex of J-PARC consists of a 181 MeV Linac, a 3 GeV Rapid-Cycling Synchrotron (RCS) and a 50 GeV Main Ring (MR). The RCS ring is designed to support 1 MW of beam and to deliver a 3 GeV pulsed proton beam to the spallation neutron target and the MR at a repetition rate of 25 Hz. Since the RCS finally accelerates very high intensity beam, the secondary electron cloud may affect the accelerator performance. The electron cloud effect in RCS was evaluated by simulations, but the secondary electron emission yield (SEY) of the chamber surface and beam loss point, lost proton number were assumed. In this Study we measured the SEY from the samples which was dealt with similar process of an actual chamber surface. We estimate the practical influence of the secondary electron cloud during beam operation.

New synthesis method of advanced lithium titanate with LiTiO additives for ITER-TBM

Hoshino, Tsuyoshi; Kato, Kenichi*; Natori, Yuri*; Nakamura, Mutsumi*; Sasaki, Kazuya*; Hayashi, Kimio; Terai, Takayuki*; Tatenuma, Katsuyoshi*

Fusion Engineering and Design, 84(2-6), p.956 - 959, 2009/06

https://doi.org/10.1016/j.fusengdes.2008.12.049

LiTiO is one of the most promising candidates among the proposed solid breeder materials for fusion reactors. Addition of H to inert sweep gas has been proposed for enhancing the release of bred tritium from breeder material. However, the mass of LiTiO was found to decrease with time in the hydrogen atmosphere. This mass change indicates that the oxygen content of the sample decreased, suggesting the change from Ti to Ti. In order to control the mass change at the time of high temperature use, the development of lithium titanate which has LiTiO additive is expected to be effective.