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Hamamoto, Shimpei; Iigaki, Kazuhiko; Shimizu, Atsushi; Sawahata, Hiroaki; Kondo, Makoto; Oyama, Sunao; Kawano, Shuichi; Kobayashi, Shoichi; Kawamoto, Taiki; Suzuki, Hisashi; et al.
JAEA-Technology 2006-030, 58 Pages, 2006/03
During normal operation of High Temperature engineering Test Reactor (HTTR) in Japan Atomic Energy Agency (JAEA), the reactivity is controlled by the Control Rods (CRs) system which consists of 32 CRs (16 pairs) and 16 Control Rod Drive Mechanisms (CRDMs). The CR system is located in stand-pipes accompanied by the Reserved Shutdown System (RSS). In the unlikely event that the CRs fail to be inserted, the RSS is provided to insert BC/C pellets into the core. The RSS shall be designed so that the reactor should be held subcriticality from any operation condition by dropping in the pellets. The RSS consists of BC/C pellets, hoppers which contain the pellets, electric plug, driving mechanisms, guide tubes and so on. In accidents when the CRs cannot be inserted, an electric plug is pulled out by a motor and the absorber pellets fall into the core by gravity. A trouble, malfunction of one RSS out of sixteen, occurred during a series of the pre-start up checks of HTTR on February 21, 2005. We investigated the cause of the RSS trouble and took countermeasures to prevent the issue. As the result of investigation, the cause of the trouble was attributed to the following reason: In the motor inside, The Oil of grease of the multiplying gear flowed down from a gap of the oil seal which has been deformed and was mixed with abrasion powder of brake disk. Therefore the adhesive mixture prevented a motor from rotating.
Kosako, Toshiso*; Nakazawa, Masaharu*; Wakabayashi, Hiroaki*; Sekiguchi, Akira*
PNC TJ260 78-06, 97 Pages, 1976/11
He proportional counter was employed to determine the fast and intermediateneutron spectra of wide energy region. The mixed gas (He, Kr) type counterresponse and the spectrum unfolding code were prepared and applied to some neutronfields. The counter response calculation was performed by using the Monte Carlocode,paying regards to dealing of the particle range calculation of the mixed gas.An experiment was carried out by using the van de Graaff accelerator to check theresponse function. The spectrum unfolding code was prepared so that it mayhave the function of automatic evaluation of the higher energy spectum's effectto the pulse hight distribution of the lower energy region. The neutron spectraof the various neutron fields were measured and compared with the calculations suchas the discrete ordinate Sn calculations. It became clear that the techniquedeveloped here can be applied to the practical use in the neutron energy rangefrom about 150 KeV to 5 MeV.
; ; Makino, Akihiro; Murano, Toru*; Wakabayashi, Hiroaki*; Yoshii, Koji*
PNC TN841 77-06, 76 Pages, 1976/03
no abstracts in English
Kawano, Yasunori; Kondoh, Takashi; Ishikawa, Masao; Hatae, Takaki; Hayashi, Toshimitsu; Ono, Takehiro; Ogawa, Hiroaki; Sugie, Tatsuo; Iwamae, Atsushi; Kusama, Yoshinori; et al.
no journal, ,
Progress in ITER diagnostics development in Japan is presented. (1) Micro Fission Chamber: A bending test of the mineral insulated cable has been carried out since its smallest bending radius would be 12 cm in the vacuum vessel. It has been confirmed that no damage has been observed even at the bending radius is small as 10 cm. (2) Thomson Scattering (Edge): It has been confirmed that the prototype YAG laser amplifier satisfies the target performance of ITER requirement. (3) Poloidal Polarimeter: Study of retro-reflectors in the first wall modules and the divertor cassette has been progressed. (4) Impurity Influx Monitor (Divertor): Mechanical designs of mirror box and optical shutter in the divertor cassette have been designed. (5) Upper Port Plug: For the generic design of the upper port plug (UPP), mesh modeling of UPP has been performed for the E-M analysis. Application of HIP (Hot Isostatic Press) method for manufacturing of UPP has been proposed.
Kawano, Yasunori; Kondoh, Takashi; Ishikawa, Masao; Ogawa, Hiroaki; Iwamae, Atsushi; Sugie, Tatsuo; Sato, Kazuyoshi; Hatae, Takaki; Yatsuka, Eiichi; Hayashi, Toshimitsu; et al.
no journal, ,
no abstracts in English
Takeuchi, Masaki; Sugie, Tatsuo; Ogawa, Hiroaki; Kusama, Yoshinori; Ebisawa, Katsuyuki*; Wakabayashi, Kunio*; Nariai, Kyoji*; Tanimoto, Aki*; Kiyohara, Motosuke*
no journal, ,
no abstracts in English