Improvement of motor control system in J-PARC linac and RCS

Takahashi, Hiroki; Miura, Akihiko; Sawabe, Yuki; Yoshimoto, Masahiro; Suzuki, Takahiro*; Kawase, Masato*

Proceedings of 9th International Particle Accelerator Conference (IPAC '18) (Internet), p.2180 - 2182, 2018/06

https://doi.org/10.18429/JACoW-IPAC2018-WEPAL015

The stepping motor control system used in the profile monitor and RCS collimator of J-PARC is configured by VME-based. Most of these pieces of control equipment are in use for more than 10 years. Therefore, countermeasures against aging of equipment are necessary. In addition, it is necessary to implement countermeasures against malfunction of the control system, which is thought to be caused by radiation. In 2016, a malfunction occurred in the motor control system of the RCS collimator. Taking this as a starting point, we began developing a motor control system that can ensure equipment safety even if a malfunction occurs. In this paper, we show the inference of the cause of this malfunction and present details of the developed high-safety motor control system.

Present status of J-PARC linac

Oguri, Hidetomo; Hasegawa, Kazuo; Ito, Takashi; Chishiro, Etsuji; Hirano, Koichiro; Morishita, Takatoshi; Shinozaki, Shinichi; Ao, Hiroyuki; Okoshi, Kiyonori; Kondo, Yasuhiro; et al.

Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.389 - 393, 2014/10

http://www.pasj.jp/web_publish/pasj2014/proceedings/PDF/FSP0/FSP021.pdf

no abstracts in English

Beam loss reduction by the beam duct realignment in the J-PARC linac beam transport line

Tamura, Jun; Ao, Hiroyuki; Asano, Hiroyuki; Ikegami, Masanori*; Maruta, Tomofumi; Miura, Akihiko; Morishita, Takatoshi; Oguri, Hidetomo; Ouchi, Nobuo; Sawabe, Yuki*; et al.

Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.377 - 380, 2013/08

http://www.pasj.jp/web_publish/pasj9/proceedings/PDF/WEPS/WEPS013.pdf

In the J-PARC linac, almost all the cavities and magnets have been precisely aligned because the accelerator tunnel has been deformed by the 2011 Tohoku Earthquake. In the beam transport line called MEBT2 and A0BT at the downstream of the drift tube linac, the beam duct has been roughly aligned after the precise alignment of the quadruple doublets. During the first beam operation after the earthquake, remarkable beam loss and residual radiation have been recognized at the MEBT2 and A0BT. As the result of the duct position measurement, the misalignement including over 10 mm shift from the beam axis was found. By conducting the beam duct realignment, the beam loss and the residual radiation were successfully decreased. In this paper, the procedure of the beam duct alignment and the beam loss due to the misalignment are described.

A Remote radiation monitoring system using an autonomous unmanned helicopter for nuclear emergencies

Okuyama, Shinichi; Torii, Tatsuo; Suzuki, Akihiko*; Shibuya, Masanori*; Miyazaki, Nobuyuki*

Journal of Nuclear Science and Technology, 45(Suppl.5), p.414 - 416, 2008/06

https://doi.org/10.1080/00223131.2008.10875877

In case of a nuclear emergency when a large amount of radioactive substances and/or radiation is released from a nuclear facility, emergency radiation monitoring is carried out from the sea and air as well as from the ground adjacent to the facility to evaluate the influence of the radiation on the surrounding environment. As a means of radiation monitoring from the air, aerial monitoring using a manned helicopter is conducted. Although a manned helicopter can monitor a large area during a short time, flight at an altitude of 300 m or lower is prohibited by the Aviation Law in Japan. Therefore, it is difficult for a manned helicopter to measure the radiation profile near the ground and to measure the radiation level in a complicated terrain. In recent years, technologies for autonomous flying of industrial unmanned helicopters have been developed and applied to natural disasters. In expectation of the application of unmanned helicopters to aerial radiation monitoring during a nuclear emergency, we have developed a remote radiation monitoring system and investigated its possibilities.

Study on the cause of the fire and explosion incident at bituminization demonstration facility of PNC Tokai Works

Sato, Yoshihiko; Koyama, Tomozo; Miura, Akihiko; ; ; Shigetome, Yoshiaki

Proceedings of 2nd International Conference on Safewaste 2000, 0 Pages, 2000/10

On march 11,1997, bituminization demonstration facility(BDF) in Tokai Reprocessing Plant (TRP) of power reactor and nuclear fuel development corporation (PNC) made fire and explosion incident. Investigation of the cause of the fire and explosion incident at BDF was carefully conducted. The main cause of the fire is clarified to have been physical heating inside the extruder that provided unusual high temperature of bituminized product at filling. Physical feating is considered to be derived from decrease of feed rate of liquid waste to the extruder. The causes of the explosion are accumulation offlammable gas generated from insufficiently extinguished bituminized product inside the filling room of which the ventilation system was shut doen. The gas was ignited by another ignition of the heated drum.

Simulation of second fire incident in the filling room (R152)

Miura, Akihiko;

JNC TN8410 99-046, 35 Pages, 1999/10

JNC-TN8410-99-046.pdf:7.29MB

Judging from several evidences which are operators' testimony, observation result, and so on, the "Committee for an Investigation into the Fire and Explosion Incident at the BDF of the Reprocessing plant of Tokai Works" concluded another fire incident occurred in the filling room (R152) after the explosion (hereafter called second fire incident). This report explains the simulation result of second fire incident. Calculated air temperature and radiation intensity are used another calculations that indicate the thermal influence from the fire name to the extruder or neighboring drums. About second fire incident, calculated result indicates first fire occurred from the No.30104 drum that was produced in 30B or several drums including No.30104 drum. It is estimated that temperature and thermal runaway reaction was not due to fire of neighboring drum because the drum doesn't receive large influence thermally by radiation from the neighboring fire name. Each result suggests the all burnt 29B and 30B drums were filled at higher temperature than usual.

Experiment using laboratory scale extruder; Fluid behavior in twin-screw extruder

; Miura, Akihiko

JNC TN8410 99-041, 215 Pages, 1999/09

JNC-TN8410-99-041.pdf:12.06MB

All evidences and chemical data suggest non-chemical heating mechanism raised the filling temperature of the bituminized product. But they indicate the filling temperature was higher than before at the incident. We estimated the physical heat mechanism in the extruder. It is well known that the viscous-heating occurs in mixing process in extruders. In order to confirm the behavior of the torque and temperature, some experiment using laboratory scale extruder were performed. The result of the experiment using laboratory scale extruder showed that the phenomena of salt enrichment and salt accumulation were observed and they raised mixture temperature at the decreased feed rate. These phenomena depend on the feed rate. It is considered that they have large contribution to heat transportation and operational torque due to the friction between screw and mixture. In this report, all experiment result are explained.

None

Shigetome, Yoshiaki; ; ; Miura, Akihiko; Sato, Yoshihiko; Koyama, Tomozo

JNC TN8200 99-001, 128 Pages, 1999/07

JNC-TN8200-99-001.pdf:92.69MB

None

None

Miura, Akihiko; ; ; ;

PNC TN8420 98-010, 43 Pages, 1998/04

PNC-TN8420-98-010.pdf:2.01MB

None

Implementation of high temperature structure monitor system using heat resistant fiber Bragg grating sensors

Shimada, Yukihiro; Nishimura, Akihiko; Suzuki, Hirokazu*; Ishibashi, Hisayoshi*; Kawahara, Hirotaka; Ito, Chikara; Aoyama, Takafumi

no journal, , 

We developed the fiber Bragg grating (FBG) sensor system with high temperature tolerance for a deterioration evaluation of passing year and seismic safety in nuclear power plant. We examined the heating tolerance and the load transformation of the reinforced FBG sensor system. As a result, the strengthening FBG sensor was an excellent adhesion performance in the environment of 400 C or less. Additionally, the load transformation examination was executed under the high temperature environment, and it was confirmed that the measurement of the amount of the transformation was possible with strengthening FBG sensor.