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Kasugai, Yoshimi; Sato, Koichi; Takahashi, Kazutoshi*; Miyamoto, Yukihiro; Kai, Tetsuya; Harada, Masahide; Haga, Katsuhiro; Takada, Hiroshi
JPS Conference Proceedings (Internet), 33, p.011144_1 - 011144_6, 2021/03
A spallation neutron source with a mercury target has been in operation at the Materials and Life Science Experimental Facility of J-PARC since 2008. The target vessel made of stainless steel is required to be exchanged periodically due to radiation damage etc. In this presentation, tritium gas release observed in the first series of exchange work in 2011 and the analytical results will be shown.
Yamamoto, Kazami; Hotchi, Hideaki; Harada, Hiroyuki; Hayashi, Naoki; Kinsho, Michikazu; Saha, P. K.; Tamura, Fumihiko; Yamamoto, Masanobu; Yoshimoto, Masahiro; Nakane, Yoshihiro; et al.
Progress in Nuclear Science and Technology (Internet), 4, p.238 - 242, 2014/04
A 3 GeV rapid cycling synchrotron (RCS) at J-PARC was commissioned in October 2007. Afterwards, the beam intensity was increased through a beam study, and the RCS has continuously provided a proton beam 
100 kW to the neutron target since October 2009. With renewed efforts brought about by beam commissioning, we have reduced losses in the RCS and achieved low-loss operation. We present the history of the operational beam power and the residual dose distributions after operation.
Nakashima, Hiroshi; Miyamoto, Yukihiro
Radioisotopes, 57(4), p.253 - 260, 2008/04
J-PARC (Japan Proton Accelerator Research Complex) is a high energy accelerator facility with the world-top-class high beam intensity. Because J-PARC has high intensity and high energy, from the viewpoint of radiation safety, J-PARC has various problems that should have been examined and overcome at the stage of design and construction. In addition, aiming at smooth and effective operation of the facility, I assumed operation pattern, management and the usage of the facility and designed some building and tunnel settled accelerators as well as some instruments to keep radiation safety. In this paper, I explained, from the various countermeasures, radiation shielding design condition and methods, handling of activated air and water in the instruments and the facility, maintenance of the activated accelerators and targets, and a radiation monitoring system.
Miyamoto, Yukihiro; Sakamaki, Tsuyoshi*; Maekawa, Osamu*; Nakashima, Hiroshi
JAERI-Tech 2004-054, 72 Pages, 2004/08
A standard is provided for the radiation monitor based on LAN (Local Area Network) and PLC (Programmable Logic Controller) technology at the introduction to the Japan Proton Accelerator Research Complex (J-PARC). The monitor consists of radiation measurement equipments and the central monitoring panel. The formers are installed in the radiation field, and the latter is installed in the control room and composed of PLC, which are connected with LAN. Extension of the existing standard and the conformity to the international standard were thought as important in providing the standard. The standard is expected to improve the compatibility, maintenancability and productivity of the components.
Miyamoto, Yukihiro
Hokeikyo Nyusu, (32), p.2 - 3, 2003/10
no abstracts in English
Miyamoto, Yukihiro; Ikeno, Koichi; Akiyama, Shigenori*; Harada, Yasunori
JAERI-Tech 2002-086, 43 Pages, 2002/11
Description is given for the characteristic radiation environment for the High Intensity Proton Accelerator Facility and the design concept of the radiation control system of it. The facility is a large scale accelerator complex consisting of high energy proton accelerators carrying the highest beam intensity in the world and the related experimental facilities and therefore provides various issues relevant to the radiation environment. The present report describes the specifications for the radiation control system for the facility, determined in consideration of these characteristics.
Miyamoto, Yukihiro; ; Harada, Yasunori
JAERI-Tech 98-039, 44 Pages, 1998/09
no abstracts in English
*; Iwashita, Tsuyoshi*; *; *; *; *; *
PNC TJ9164 96-020, 68 Pages, 1996/03
JOYO Simulator(FOSTER) has been operated for operational training and also evaluation of specific operation such as low coolant flow test. On the other hand, it is necessary to utilize FOSTER for characteristics evaluation of various special operation. In 1994, we carried out arrangement of remodeling items fbr MK-III plan and improvement of simulation performance. In this study, we designed program of dynamic model to realize simulator of MK-III plant with high accuracy. We designed program to improve precision of simulation of reactor core and heat balance. We designed software and hardware to improve a responsibility of nuclear instrumentation, and selected specification of hardware. For improvement of scheduling function and training of emergency procedure guidelines. We designed visual display investigated replacement of simulator computer system.
Iwashita, Tsuyoshi*; *; *; *; *
PNC TJ9164 96-001, 69 Pages, 1996/01
JOYO simulator(FOSTER) has been operated for operational training and also evaluation of specific operation such as low coolant flow test. This study was carried out for arrangement of remodeling items for MK-III and for improvement of simulation performance. At first, in order to improve preciseness of simulation of normal operation and abnormal operation by FOSTER, we evaluated simulation results of FOSTER and FBR plant dynamic analysis code MIMIR-N2, selecting typical eight event. We confirmed that Foster has satisfactory simulation excepting behavior of natural circulation condition and low coolant low condition. Also, in order to improve simulation accuracy of control rod reactivity and response of NIS indication, we investigated details for improvement of soft-ware and hardware, and arranged remodeling items for MK-III. For strengthen supervisory function of plant condition, we designed monitoring display for non-measured parameter and emergency condition.
Nakashima, Hiroshi; Shibata, Tokushi; Sawahata, Kei; Miyamoto, Yukihiro; Nakane, Yoshihiro; Masukawa, Fumihiro; Seki, Kazunari; Sato, Koichi; Oguri, Tomomi*; Hirayama, Hideo*; et al.
no journal, ,
Aiming at studies on the latest basic science and the advancing nuclear technology, the J-PARC (Japan Proton Accelerator Research Complex) project is in progress, and the high-energy proton accelerator complex of the world highest intensity is under construction. Because of its very high beam power and its energy as well as the large-scale accelerator complex, we have encountered some difficult radiation problems in the radiation safety design. This paper reviews the radiation safety policy and methods for the design to overcome the problems on the radiation safety and the status of the radiation safety estimation for licensing of J-PARC.
Miyamoto, Yukihiro; Fujimoto, Toshiaki*; Ito, Katsuhito*; Yasutomo, Katsumi*; Kamiya, Eisei*
no journal, ,
no abstracts in English
Miyamoto, Yukihiro
no journal, ,
no abstracts in English
Miyamoto, Yukihiro
no journal, ,
no abstracts in English
Nakazawa, Takashi; Sato, Koichi; Miyamoto, Yukihiro; Nakashima, Hiroshi; Kasugai, Yoshimi; Kai, Tetsuya; Oi, Motoki; Miura, Taichi*; Takahashi, Kazutoshi*
no journal, ,
Radioactive nuclide activated in the mercury target of Materials and Life-Science Experimental Facility of J-PARC, the measurement results of the dose rate around the mercury target and the safety measures for radiation are reported.
Seki, Kazunari; Otsuka, Norikazu; Miyamoto, Yukihiro
no journal, ,
no abstracts in English
Hg in J-PARC Materials & Life Science Experimental FacilitySato, Koichi; Masuyama, Koichi; Tajima, Takahiro; Yoshino, Koji; Seki, Kazunari; Kasugai, Yoshimi; Miyamoto, Yukihiro
no journal, ,
Various kinds of experiments on material and biological science have been carried out using neutrons and muons generated by bombarding the mercury and muon target with high-energy (3 GeV) and high-intense (1MW) protons in the Materials and Life Science Experimental Faculty (MLF) of Japan Proton Accelerator Complex (J-PAPC). It was found that radioactive nuclide of Hg induced in the mercury target during the beam operation was released to the environment via the ventilation system from the stack at specific times during maintenance periods. The weekly-average concentrations of Hg in the stack were 2.4 
10
1.5 10
Bq/cm
, which was much less than the legal limit by a factor of 1/10,000. The release behavior of Hg will be reported in the presentation.
Masuyama, Koichi; Sato, Koichi; Yoshino, Koji; Tajima, Takahiro*; Seki, Kazunari; Kasugai, Yoshimi; Miyamoto, Yukihiro
no journal, ,
The mercury target vessel used in the Materials and Life Science Experimental Facility (MLF) in the Japan Accelerator Research Complex (J-PARC) needs to be replaced periodically. The replacement work, which is conducted in the hot cell, associates with release of radioactive materials produced via spallation reactions between protons and mercury. Therefore we monitored radioactivity of dust and air samples in the hot cell. By the monitoring, we newly found peculiar phenomena on the behavior of radioactive products, which is important for radiation control. In this work, we will show the monitoring data and the new observation.
Kasugai, Yoshimi; Sato, Koichi; Masuyama, Koichi; Seki, Kazunari; Miyamoto, Yukihiro; Kai, Tetsuya; Harada, Masahide; Haga, Katsuhiro; Takada, Hiroshi
no journal, ,
no abstracts in English
Saito, Fumihiro; Masukawa, Fumihiro; Seki, Kazunari; Kasugai, Yoshimi; Miyamoto, Yukihiro
no journal, ,
no abstracts in English
Kasugai, Yoshimi; Sato, Koichi; Takahashi, Kazutoshi*; Miyamoto, Yukihiro; Kai, Tetsuya; Harada, Masahide; Haga, Katsuhiro; Takada, Hiroshi
no journal, ,
A spallation neutron source of mercury has been operated in the Materials and Life Science Experimental Facility of J-PARC. A stainless vessel containing mercury during the operation has been exchanged periodically. During the exchange work, tritium release has been observed. The behavior and an analysis from a viewpoint of tritium absorption and emission from stainless steel are reported.
