JOPSS - Search Results

Journal Articles

Progress of target system operation at the pulsed spallation neutron source in J-PARC

Takada, Hiroshi; Naoe, Takashi; Kai, Tetsuya; Kogawa, Hiroyuki; Haga, Katsuhiro

Proceedings of 12th International Topical Meeting on Nuclear Applications of Accelerators (AccApp '15), p.297 - 304, 2016/00

In J-PARC, we have continuously been making efforts to operate a mercury target of a pulsed spallation neutron source with rated power of 1-MW. One of technical progresses is to mitigate cavitation damages at the target vessel front induced by the 3-GeV proton beam injection at 25 Hz. We have improved the performance of a gas micro-bubbles injection into the mercury target, resulting that no significant cavitation damages was observed on the inner surface of target vessel after operation for 2050 MWh with the 300-kW proton beam. Another progress is to suppress the release of gaseous radioactive isotopes, especially tritium, during the target vessel replacement. We have introduced a procedure to evacuate the target system by an off-gas processing apparatus when it is opened during the replacement operation, achieving to suppress the tritium release through the stack. For example, the amount of released tritium was 12.5 GBq, only 5.4% of the estimated amount, after the 2050 MWh operation. After these progresses, the operating beam power for the pulsed spallation neutron source was ramped up to 500-kW in April, 2015.

JAEA Reports

J-PARC materials and life science facility experimental apparatus installation manual, 1

Neutron Facility Group

JAERI-Tech 2004-059, 106 Pages, 2004/10

JAERI-Tech-2004-059.pdf:6.82MB

The Materials and Life Science Facility is being constructed as one of main facilities in the JAERI-KEK High-Intensity Proton Accelerator Project (J-PARC). Various experimental apparatuses will be installed in 1st and 2nd Experimental Halls in the facility building. Neutron and muon beams provided by the facility are to be utilized for experimental research. This manual provides facility-side information that is needed for designing and installing experimental apparatuses, and summarizes specifications of junction points between the facility-side and user-side as of June, 2004.

Journal Articles

New trial of teaching material for education; The World near the light speed and virtual reality, Star bow

Ueshima, Yutaka

Dai-8-Kai Bijuarizeshon, Kanfarensu Rombunshu (CD-ROM), 12 Pages, 2002/10

The theory of special relativity found by Einstein is famous. It is one of the most important theories for our research on interactions between ultra-intense lasers and matters. The Name of the theory is well-known, although the understanding of that world is quite difficult. Therefore, we developed software to experience the special relativistic world with OPENGL Scene Graph. The software has not only normal display mode but also a projection mode of a simple virtual reality apparatus using polarizing filters. With the software, the relativistic distortion of a visual field and the Doppler effect near light speed can be expressed. It is difficult for a teacher to teach these relativistic effects with graphs and formulae. This software and simple virtual reality apparatus have already been used in the Ishikawa-e-Science2002, JAERI-Kyoto-Science Camp2002 and a lot of visitor tours in JAERI(Kizu). A lot of people were interested in these relativistic effects after the demonstration.

JAEA Reports

Inspection of heat transfer tubes after mock-up tests of minituarized apparatus for the acid recovery evaporator (Contract research)

Hamada, Shozo; Fukaya, Kiyoshi*; Kato, Chiaki; Yanagihara, Takao; Doi, Masamitsu*; Kiuchi, Kiyoshi

JAERI-Tech 2001-063, 49 Pages, 2001/10

JAERI-Tech-2001-063.pdf:13.39MB

The demonstration test for the acid recovery evaporator and the dissolver used in the major equipment of Rokkasho Reprocessing Plant (RRP), has been carried out. The mock-up miniature equipment has been employed to it. This test had been performed from April in 1998. The total time of demonstration test using the mock-up equipment is about two and half years, which corresponds to about 20,000 hours. After that, four of the seven heat transfer tubes used in the evaporator were drawn out and the corrosion level and the mechanical properties were evaluated for one of them. As a result, intergranular corrosion was recognized in the inner surface of the heat transfer tube and the corrosion depth at the grain boundary was statistically shown to be about one grain from the inner surface. Further, no change in mechanical properties was observed and growth of intergranular cracks in the inner surface of the specimen was found after flattering test.

JAEA Reports