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Sekita, Kenji; Arakaki, Etsushi; Wakabayashi, Hiroshi
JAEA-Technology 2010-036, 42 Pages, 2010/11
JAEA-Technology-2010-036.pdf:2.9MB
The Liquid Nitrogen (LN
) manufacturing facility in HTTR, is a high-pressure gas manufacturing facility. The facility provides LN to cold charcoal trap (CCT) in primary and secondary helium purification systems, impurities gas trap for gas chromatography mass spectrometer in primary and secondary helium sampling systems. The facility has been performed periodical inspection according to the law and rule, and each inspection item satisfied the judgment value. Thus, it was confirmed that the maintenance of LN manufacturing facility was appropriate. In addition, the effective and efficient LN amount to be consumed was clarified on the basis of the monitoring. Results of the liquid level of the storage tank and the consumption of LN as the reactor was operated or stopped, by considering the filling frequency and amount of the filling of LN to the facility by a tank lorry. This report describes method and result of periodical inspection and equipment management.
Yamazaki, Kazunori; Kameyama, Yasuhiko; Inoi, Hiroyuki; Arakaki, Etsushi; Shinozaki, Masayuki; Ota, Yukimaru
JAEA-Testing 2008-002, 52 Pages, 2008/03
JAEA-Testing-2008-002.pdf:15.54MB
The High Temperature Engineering Test Reactor (HTTR) has the Gaseous Radwaste Treatment System (GRTS). This system appropriately collects all potentially radioactive gases discharged from the plant. After the gases are decayed with the Decay tank and decreased with the Filtering system, the gases are discharged into the atmosphere under monitoring. This system is maintained every year for keeping the performance. The maintenance is very important. Furthermore, the maintenance is profitable for designing a new High Temperature Gas cooled Reactor. This report describes the newly developed, maintenance items and improvements of the GRTS.
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
JAEA-Technology-2006-030.pdf:10.69MB
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 B
C/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.