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Journal Articles

FRP insulator column for high current accelerator of ITER; International thermonuclear experimental reactor

Inoue, Takashi

Kyoka Purasuchikkusu, 60(7), p.269 - 270, 2014/07

In ITER as a thermonuclear fusion experimental reactor being conducted by an international project, a large bore insulator ring of about 1.8 m in diameter is required for generation of 1 MeV, 40 A ion beam for plasma heating by Neutral Beam Injector. At JAEA, R&D has been carried out for development of such large bore insulator ring made of ceramics, and in parallel, ion beam experiments have been carried out with insulator rings made of FRP. The experiments have troubled with frequent high voltage breakdowns after outgas from FRP. Finding melt epoxy traces at triple junction (interface of vacuum, metal and FRP as dielectric material), local stress at the triple junction has been mitigated by mounting a large metal structure, so called stress ring. As a result, acceleration of 0.98 MeV, 185 A/m $^{2}$ hydrogen negative ion beam has successfully achieved in short pulses, where the requirement by ITER is 1 MeV and 200 A/m $^{2}$ .

Journal Articles

Modification of elastic poly(lactic acid) by radiation-induced crosslinking

Nagasawa, Naotsugu; Tamada, Masao; Kanazawa, Shinichi*; Hayasaki, Toshikatsu*

Purasuchikkusu, 58(11), p.45 - 48, 2007/11

https://ci.nii.ac.jp/naid/40015700058

Poly(lactic acid), PLA was irradiated using electron beams in the presence of triallyl isocyanurate at 5 phr concentration as crosslinking agent. The crosslinked PLA, of which heat resistance was improved, is applied on flexible and elastic materials by addition of plasticizer or immersion in plasticizer. The elastic PLA material has several advantages such as high holding plasticizer, heat resistance at 80 $^{circ}$ C and transparency. It is therefore proven that crosslinking technology is beneficial to expanding application of soften PLA.

Journal Articles

Development of high performance polymer electrolyte fuel cell membrane by -irradiation process

Asano, Masaharu; Chen, J.; Maekawa, Yasunari; Yoshida, Masaru

Purasuchikkusu, 57(5), p.9 - 15, 2006/05

http://ci.nii.ac.jp/naid/40007292695

To development a high chemical stable proton exchange membrane for application in DMFC, four styrene derivative monomers, p-methylstyrene (MeSt), p-tert-butylstyrene (tBuSt), divinylbenzene (DVB) and bis(vinyl phenyl) ethane (BVPE) were graft copolymerized into the poly(ethylene-co-tetrafluoroethylene) (ETFE) film by a radiation graft technique and followed by sulfonation the grafted ETFE film. Ion exchange capacity (IEC), proton conductivity, water uptake, chemical stability and methanol permeability of the proton exchange membrane were determined. The four monomers-grafted membrane with proton conductivity as high as Nafion membrane was several times stabler than the traditional styrene/DVB-grafted membrane, and five times lower methanol permeability compared to Nafion 112 membrane. Therefore, the developed four monomers-grafted membrane was a more promising material for the application in DMFC.

Journal Articles