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Shimizu, Atsushi; Furusawa, Takayuki; Homma, Fumitaka; Inoi, Hiroyuki; Umeda, Masayuki; Kondo, Masaaki; Isozaki, Minoru; Fujimoto, Nozomu; Iyoku, Tatsuo
Journal of Nuclear Science and Technology, 51(11-12), p.1444 - 1451, 2014/11
Times Cited Count：1 Percentile：8.82(Nuclear Science & Technology)JAEA has kept up a data-base system of operation and maintenance experiences of the HTTR. The objective of this system is to share the information obtained operation and maintenance experiences and to make use of lessons learned and knowledge into a design, construction and operation managements of the future HTGR. More than one thousand records have been registered into the system between 1997 and 2012. This paper describes the status of the data-base system, and provides suggestions for improvement from four experiences: (1) performance degradation of helium compressors; (2) malfunction of reserved shutdown system in reactivity control system; (3) maintenance experiences of emergency gas turbine generators; and (4) experiences of the Great East Japan Earthquake. These experiences are extracted from the system as important lessons learned to be expected to apply for design, construction and operation managements of future HTGR.
Shinohara, Masanori; Yanagi, Shunki; Tochio, Daisuke; Shimazaki, Yosuke; Nojiri, Naoki; Owada, Hiroyuki; Sato, Nao; Sagawa, Hiroshi; Umeda, Masayuki
JAEA-Technology 2011-029, 39 Pages, 2011/12
JAEA-Technology-2011-029.pdf:3.03MB
JAEA plans and performs the safety demonstration test using the HTTR to develop High Temperature Gas Reactor technologies. Cold test of the loss of forced cooling was conducted prior to the safety demonstration test, to check test procedure and plant behavior. Cold test consists of two phases, Phase1, 1 or 2 Vessel Cooling System (VCS) terminates, in the Phase2, all 3 Gas circulators and 1 VCS terminates. Cold test could confirm test process, and obtain data necessary to analysis and 2-dimensional horizontal sectional model analysis was verified to simulate actual measurement value.
Tomimoto, Hiroshi; Hamamoto, Shimpei; Tochio, Daisuke; Ueta, Shohei; Umeda, Masayuki; Nishihara, Tetsuo
JAEA-Technology 2009-026, 37 Pages, 2009/08
JAEA-Technology-2009-026.pdf:8.9MB
HTTR (High Temperature Engineering Test Reactor) loaded the first driver fuel in July 1998 and reached first criticality state in November 1998. After power increasing examination, HTTR has been conducting safety demonstration test and sequentially acquiring basic technical data of high temperature gas cool reactor. Temperature measurement inside the reactor is planed in the next midterm plan to improve HTTR performance. This report describes the investigation result of fuel temperature measurement method which is applicable to critical irradiation test.
Tomimoto, Hiroshi; Kato, Yasushi; Owada, Hiroyuki; Sato, Nao; Shimazaki, Yosuke; Kozawa, Takayuki; Shinohara, Masanori; Hamamoto, Shimpei; Tochio, Daisuke; Nojiri, Naoki; et al.
JAEA-Technology 2009-025, 29 Pages, 2009/06
JAEA-Technology-2009-025.pdf:21.78MB
The first driver fuel of the HTTR (High Temperature Engineering test Reactor) was loaded in 1998 and the HTTR reached first criticality state in the same year. The HTTR has been operated using the first driver fuel for a decade. In Fuel elements assembling, 4770 of fuel rods which consist of 12 kinds of enrichment uranium are loaded into 150 fuel graphite blocks for HTTR second driver fuel elements. Measures of prevention of fuel rod miss loading, are employed in fuel design. Additionally, precaution of fuel handling on assembling are considered. Reception of fuel rods, assembling of fuel elements and storage of second driver fuels in the fresh fuel storage rack in the HTTR were started since June, 2008. Assembling, storage and pre-service inspection were divided into three parts. The second driver fuel assembling was completed in September, 2008. This report describes concerns of fuel handling on assembling and storage work for the HTTR fuel elements.
Tomimoto, Hiroshi; Umeda, Masayuki; Nishihara, Tetsuo; Iyoku, Tatsuo
UTNL-R-0471, p.11_1 - 11_9, 2009/03
The first driver fuel of the HTTR (High Temperature Engineering test Reactor) was loaded in 1998 and the HTTR reached first criticality state in the same year. The HTTR has been operated using the first driver fuel for a decade. HTTR reactor core consist of twelve kinds of enriched uranium fuel elements. Fuel rods were designed for avoiding fuel rod false loading because fuel rods number is 4770, and it was considered on handling. Reception of fuel rods, assembling of fuel elements and storage of second driver fuels in the fresh fuel storage rack in the HTTR were started since June, 2008. Pre-service inspection was finished. And the second driver fuel assembling was completed in September, 2008. This report describes concerns of fuel handling on assembling and storage work for the HTTR fuel elements.
Ueta, Shohei; Tobita, Tsutomu*; Sawa, Kazuhiro; Tomimoto, Hiroshi; Kozawa, Takayuki; Inoi, Hiroyuki; Umeda, Masayuki
JAEA-Research 2008-096, 34 Pages, 2009/01
JAEA-Research-2008-096.pdf:10.12MB
The temperature monitors for fuel blocks in high temperature gas reactors during operation are being developed. The temperature monitors consist of alloy wires, with various melting points, sealed in quarts capsules. The temperature can be evaluated in the range from 600 to 1400 
C with 22 types of the temperature monitors. The temperature monitors have been irradiated by the capsule in JMTR, and then, PIEs such as X-ray radiograph and EPMA have been carried out. As the results of the PIE, it was estimated that the temperature monitors can be used up to 90 days at 1100 C, or up to 50 days at 1300
1350 C.
Ueta, Shohei; Umeda, Masayuki; Sawa, Kazuhiro; Sozawa, Shizuo; Shimizu, Michio; Ishigaki, Yoshinobu; Obata, Hiroyuki*
Journal of Nuclear Science and Technology, 44(8), p.1081 - 1088, 2007/08
Times Cited Count：4 Percentile：31.38(Nuclear Science & Technology)The future post-irradiation program for the first-loading fuel of the HTTR is scheduled using the HTTR fuel handling facilities and the Hot Laboratory in the Japan Materials Testing Reactor (JMTR) to confirm its irradiation performance and to obtain data on its irradiation characteristics in the core. This report describes the result of preliminary test and the future plan for post-irradiation examination for the HTTR fuel. In the preliminary test, dimension measurement, weight measurement, fuel failure fraction measurement, burnup measurement, X-ray radiograph, SEM and EPMA observations have been carried out. Finally, it was confirmed that the first-loading fuel of the HTTR showed good quality under irradiation condition.
Nakagawa, Shigeaki; Umeda, Masayuki; Beddingfield, D. H.*; Menlove, H. O.*; Yamashita, Kiyonobu
JAEA-Technology 2007-003, 24 Pages, 2007/02
JAEA-Technology-2007-003.pdf:3.61MB
As of the safeguards approach in the HTTR facility, an unattended spent fuel flow monitor (UFFM) was applied to carry out an item counting of spent fuel blocks. The UFFM is so designed and fabricated as to be the compact and unique monitor system to verify a movement of spent fuel blocks in "difficult to access" area and reduce inspection efforts. This system consists of two detector packages, electronics and computer. One package consists of two ionization chambers and a He-3 counter. The IAEA acceptance tests were performed and it was confirmed the followings: (1) All the detectors were functioning properly to measure a spent fuel block flow. (2) The time difference between detector signals was sufficient to determine the direction of the spent fuel blocks. (3) The UFFM was useful to carry out the item counting. The UFFM was approved as the IAEA safeguards equipment in the safeguards approach in the HTTR.
Nojiri, Naoki; Tochio, Daisuke; Hamamoto, Shimpei; Umeda, Masayuki; Fujimoto, Nozomu; Iyoku, Tatsuo; Takeda, Tetsuaki
JAEA-Data/Code 2006-022, 61 Pages, 2006/10
JAEA-Data-Code-2006-022.pdf:5.68MB
For the future HTGR development and the management of the High Temperature engineering Test Reactor (HTTR), the HTTR operation data base is constructed. The data base consists of the sorted or evaluated data based on the measured values from the HTTR's operation such as excess reactivity of the core, temperature at facilities of the core and the plant, impurity in coolant and so on. The data base also consists of some sub-databases which have objects related to the future HTGR development or the HTTR's operational management in order to manage the important operation data systematically on a long term. This paper describes the outline and structure of the HTTR operation data base. Also, as an example, some part of the HTTR common data-base, the HTTR nuclear characteristics data-base and the Helium purity control data-base are described.
Ueta, Shohei; Izumiya, Toru; Umeda, Masayuki; Ishigaki, Yoshinobu; Ohashi, Jumpei*; Iyoku, Tatsuo
JAEA-Data/Code 2006-009, 129 Pages, 2006/03
JAEA-Data-Code-2006-009.pdf:12.35MB
The fabrication of the 2nd loading fuel for the HTTR has been started from October 2002 and completed successfully by March 2005. While the fabrication of the 2nd loading fuel for the HTTR, the fuel kernels, coated fuel particles and fuel compacts has inspected to compared with fuel fabrication specification. As the result of these inspections, we confirmed a good quality of the 2nd loading fuel for the HTTR as similarly the first loading fuel for the HTTR. This report describes fabrication data of fuel kernels, coated fuel particle and fuel compacts of HTTR 2nd loading fuel. The fabrication data of this report could be the basis of the study of fuel and fission product release behavior etc. on the HTTR operation, and contribute to post irradiation examinations of HTTR fuel in the future.
Ueta, Shohei; Takada, Eiji*; Sumita, Junya; Shimizu, Atsushi; Ashikagaya, Yoshinobu; Umeda, Masayuki; Sawa, Kazuhiro
JAERI-Tech 2004-047, 87 Pages, 2004/06
JAERI-Tech-2004-047.pdf:6.24MB
In the radiation shielding design of the High Temperature Engineering Test Reactor (HTTR), strong attention is needed to avoid especially upward neutron streaming. Shielding performance test have been carried out in the Rise-to-power test up to full power operation of 30MW. The measured dose equivalent rates in unrestricted area were lower than the detection limit for neutron-ray, and background level for 
-ray. The neutron dose equivalent rate measured in the stand pipes room was about 120
Sv/h at full power operation, which was much lower than the shielding design (330 mSv/h) and the prediction (10 mSv/h).
Takada, Eiji*; Fujimoto, Nozomu; Nojiri, Naoki; Umeta, Masayuki; Kokusen, Shigeru; Ashikagaya, Yoshinobu
JAERI-Data/Code 2002-009, 83 Pages, 2002/05
JAERI-Data-Code-2002-009.pdf:3.51MB
Dose equivalent rate around the fuel handling machine, the control rod handling machine, stand pipe compartment, maintenance pit were measured during gamma ray measurements from HTTR fuel, which was called as “power distribution measurements". The power distribution measurement was the first time to handle the fuel blocks irradiated in the core. Dose equivalent rate measurement aiming the check of shielding performance of components, the check of unexpected streaming path. The radiation monitoring during operation was carried out. As the results, there was no problem on shielding. The measured data at operation condition were also obtained. The data will be useful to expect operation circumstance in the future.
ray from fuel of High Temperature Engineering Test Reactor; Method of measurement and resultsFujimoto, Nozomu; Nojiri, Naoki; Takada, Eiji*; Yamashita, Kiyonobu; Kikuchi, Takayuki; Nakagawa, Shigeaki; Kojima, Takao; Umeta, Masayuki; Hoshino, Osamu; Kaneda, Makoto*; et al.
JAERI-Tech 2001-002, 64 Pages, 2001/02
JAERI-Tech-2001-002.pdf:3.64MB
no abstracts in English
Yamashita, Kiyonobu; Fujimoto, Nozomu; Takeuchi, Mitsuo; Fujisaki, Shingo; Nakano, Masaaki*; Umeta, Masayuki; Takeda, Takeshi; Mogi, Haruyoshi; Tanaka, Toshiyuki
Nihon Genshiryoku Gakkai-Shi, 42(1), p.30 - 42, 2000/01
Times Cited Count：3 Percentile：26.4(Nuclear Science & Technology)no abstracts in English
Yanagisawa, Kazuaki; Soyama, Kazuhiko; Ichikawa, Hiroki; ; Hoshino, Osamu; ; ; ; Kanazawa, Hiroyuki; Kimura, Yasuhiko; et al.
JAERI-M 91-114, 67 Pages, 1991/08
no abstracts in English
Inabe, Teruo; Ishijima, Kiyomi; Tanzawa, Sadamitsu; Shimazaki, Junya; Nakamura, Takehiko; ; ; ; ; ; et al.
JAERI-M 88-113, 55 Pages, 1988/06
no abstracts in English
Kawasaki, Kozo; Umeda, Masayuki
no journal, ,
no abstracts in English
Hamamoto, Shimpei; Oyama, Sunao; Emori, Koichi; Umeda, Masayuki; Sakaba, Nariaki
no journal, ,
no abstracts in English
Ueta, Shohei; Aihara, Jun; Inoi, Hiroyuki; Umeda, Masayuki; Sawa, Kazuhiro
no journal, ,
Behavior of HTTR fuel during long term high temperature operation has been examined, which was evaluated by periodical measurements of radioactivities of fission products (FPs) by primary coolant sampling. Fractional release of 
Kr during the operation became 10
, how is 10
times lower than the design limit. The most dominant reason for very good retention against FP in HTTR fuel was to accomplish very low initial through-coatings failure fraction at commercial fabrication, about 2
10
, how is 10
times lower than the design limit. Technical developments such as optimizations of fuel coating and compaction processes made the fuel failure fraction very low. Also, experimental results well agreed with the evaluation by FP gas release model. It was revealed that releases of FP gases from fuel change from recoil to diffusion by increasing fuel temperature as reactor power increases, and release from uranium contamination becomes dominant during this long term high temperature operation.
