Insights Concerning the Fukushima Daiichi Nuclear Accident, Vol.4; Endeavors by Scientists, p.341 - 356, 2021/10
Uwaba, Tomoyuki; Nemoto, Junichi*; Ito, Masahiro*; Ishitani, Ikuo*; Doda, Norihiro; Tanaka, Masaaki; Otsuka, Satoshi
Nuclear Technology, 207(8), p.1280 - 1289, 2021/08
Computer codes for irradiation behavior analysis of a fuel pin and a fuel pin bundle and for coolant thermal hydraulics analysis were coupled into an integrated code system. In the system, each code provides data required by other codes and the analyzed results are shared among them. The system allows for the synthesizing of analyses of thermal, chemical and mechanical behaviors in a fuel subassembly under irradiation. A test analysis was made for a fuel subassembly containing a mixed oxide fuel pin bundle irradiated in a fast reactor. The results of the analysis were presented with transverse cross-sectional images of the fuel subassembly and three-dimensional images of a fuel pin and fuel pin bundle models. For detailed evaluation, various irradiation behaviors of all fuel pins in the subassembly were analyzed and correlated with irradiation conditions.
Kakiuchi, Kazuo; Udagawa, Yutaka; Amaya, Masaki
Annals of Nuclear Energy, 155, p.108171_1 - 108171_11, 2021/06
Li, F.; Mihara, Takeshi; Udagawa, Yutaka; Amaya, Masaki
Journal of Nuclear Science and Technology, 57(6), p.633 - 645, 2020/06
Taniguchi, Yoshinori; Udagawa, Yutaka; Amaya, Masaki
Annals of Nuclear Energy, 139, p.107188_1 - 107188_7, 2020/05
Udagawa, Yutaka; Mihara, Takeshi; Taniguchi, Yoshinori; Kakiuchi, Kazuo; Amaya, Masaki
Annals of Nuclear Energy, 139, p.107268_1 - 107268_9, 2020/05
Dostl, M.*; Rossiter, G.*; Dethioux, A.*; Zhang, J.*; Amaya, Masaki; Rozzia, D.*; Williamson, R.*; Kozlowski, T.*; Hill, I.*; Martin, J.-F.*
Proceedings of Annual Topical Meeting on Reactor Fuel Performance (TopFuel 2018) (Internet), 10 Pages, 2018/10
Nihon Genshiryoku Gakkai Wabun Rombunshi, 14(1), p.51 - 61, 2015/03
BC used mainly for BWR and EPR absorbers could cause phenomena which never happen in PWR with Ag-In-Cd absorbers during severe accident. BC would make a eutectic interaction with stainless steel and enhance melt relocation. Boron oxidation could increase H generation and change of liberated carbon to CH could enhance CHI generation. HBO generated during BC oxidation could be changed to CsBO by combining with Cs. This may increase Cs deposition in reactor coolant system. There could be differences in configuration, surface area, stainless steel-BC weight ratio between BC powder and pellet absorbers. Present issue is to clarify effect of these differences on full scale melt progression, BC oxidation and source term. Advancement of this research domain could contribute to further sophistication of prediction tool for melt progression and source terms, and treatment of organic iodide formation in safety evaluation.
Mizuhashi, Kiyoshi; Uno, Sadanori; Okoshi, Kiyonori; Chiba, Atsuya; Yamada, Keisuke; Saito, Yuichi; Ishii, Yasuyuki; Sakai, Takuro; Sato, Takahiro; Yokota, Wataru; et al.
JAEA-Review 2005-001, TIARA Annual Report 2004, P. 371, 2006/01
no abstracts in English
Verzilov, Y. M.; Ochiai, Kentaro; Nishitani, Takeo
Fusion Science and Technology, 48(1), p.650 - 653, 2005/07
no abstracts in English
Amaya, Masaki; Sugiyama, Tomoyuki; Fuketa, Toyoshi
Journal of Nuclear Science and Technology, 41(10), p.966 - 972, 2004/10
Pulse irradiation simulating RIA condition was carried out for test rod prepared from fuel irradiated in a commercial reactor. After the pulse irradiation, optical microscopy (OM) and scanning electron microscopy (SEM) observations and electron probe micro analysis (EPMA) were conducted for the test rod as a part of destructive tests. Fission gas release behavior during pulse irradiation was investigated by EPMA and puncture test. Xeon depression was observed in the fuel pellet after pulse irradiation at periphery and center region. It is considered that fission gas was mainly released from the pellet center region during pulse irradiation. The amount of xenon release during pulse irradiation was estimated to be 10-12% from the EPMA results and this estimated value was comparable with the puncture test result. Comparing the estimated value with other results of out-of-pile annealing tests, it was concluded that most fission gas, which was accumulated at grain boundary during base irradiation, was released from the center region of test fuel pellet during pulse irradiation.
Suzuki, Motoe; Uetsuka, Hiroshi; Saito, Hiroaki*
Nuclear Engineering and Design, 229(1), p.1 - 14, 2004/04
Mechanical load on cladding induced by fuel swelling in a high burn-up BWR type rod has been analyzed by a fuel performance code FEMAXI-6. The code has been developed for the analysis of LWR fuel rod behaviors in normal operation and transient conditions using FEM. During a power ramp for the high burn-up rod, instantaneous pellet swelling can significantly exceed the level that is predicted by a "steady-rate" swelling model, causing a large circumferential strain in cladding. This phenomenon has been simulated by a new swelling model to take into account the fission gas bubble growth, and as a result it has been found that the new model can give reasonable predictions on cladding diameter expansion in comparison with post-irradiation data. In addition, a pellet-clad bonding model which has been incorporated in the code to assume firm mechanical coupling between pellet outer surface and cladding inner surface has predicted the generation of bi-axial stress state in the cladding during ramp.
Hatakeyama, Yuichi; Sudo, Kenji; Kanazawa, Hiroyuki
JAERI-Tech 2004-033, 29 Pages, 2004/03
The amount of fission gas (Kr, Xe) in irradiated fuel pellet increases with extending the burn up and that exerts a serious influence upon thermal and mechanical properties of light water reactor fuel. Therefore, the accumulation of the data on the release behavior of fission gas is important in the investigation program of safety and reliability for extended burn up fuel. In the post irradiation examination at the Reactor Fuel Examination Facility in JAERI,the fission gas which released into the plenum region from UO pellet during irradiation has been measured by puncturing test of irradiated fuel rod. The results of puncturing test show the most of fission gas remained in the pellet. It can be seen that the additional release of fission gas might occur under higher burn up and accident conditions. To know the fission gas release behavior from irradiated fuel, the Out Gas analyzer(OGA)which has the performance to heat up the UO pellet stepwise up to 2300C and to measure the released fission gas instantly from the pellet has been developed and installed at RFEF.
Suzuki, Motoe; Saito, Hiroaki*
JAERI-Data/Code 2003-019, 423 Pages, 2003/12
A light water reactor fuel analysis code FEMAXI-6 is an advanced version which has been produced by integrating the former version with a number of improvements. In particular, the FEMAXI-6 code has attained a complete coupled solution of thermal analysis and mechanical analysis, permitting an accurate prediction of pellet-clad gap size and PCMI in high burnup fuel rods. Also, such new models have been implemented as pellet-clad bonding and fission gas bubble swelling, and the coupling with burning analysis code has been enhanced. Furthermore, a number of new materials properties and parameters have been introduced. With these advancements, the FEMAXI-6 code is a versatile tool not only in the normal operation but also in transient conditions. This report describes the design, basic theory, models and numerical method, improvements, and model modification. In order to facilitate effective and wide-ranging application of the code, formats and methods of input/output, and a sample output in an actual form are included.
Polevoi, A. R.*; Sugihara, Masayoshi; Takenaga, Hidenobu; Isayama, Akihiko; Oyama, Naoyuki; Loarte, A.*; Saibene, G.*; Pereverzev, G. V.*
Nuclear Fusion, 43(10), p.1072 - 1076, 2003/10
ITER operational scenarios with the high field side pellet fuelling are considered. The possibility of reducing the energy losses per edge localised mode (ELM) to an acceptable level is discussed. Requirements on the pellet fuelling system for desirable ELM energy reduction are obtained. Self-consistent transport simulations of pellet fuelled scenarios reveal the possibility of the operation with moderate ELM losses, plasma density below Greenwald density, high energy multiplication factor Q20 and power across the separatrix above the L-H mode power threshold.
Yamamoto, Takumi; JT-60 Team
Fusion Engineering and Design, 66-68, p.39 - 48, 2003/09
Development of technology on facilities for JT-60U and resultant progress of the plasma performance are reported. The main objectives of JT-60U are to demonstrate integrated high plasma performance that contributes to establishment of the physical and technological bases of ITER and a steady state tokamak fusion reactor. Recently, performance exploration in advanced tokamak regimes has been conducted intensively, by using 500 keV negative-ion based neutral beam injection (N-NBI) and 110GHz electron cyclotron (EC) systems for plasma heating and current drive, and a repetitive centrifugal pellet injector for efficient core particle fueling.
Takase, Haruhiko*; Tobita, Kenji; Nishio, Satoshi
JAERI-Data/Code 2003-013, 46 Pages, 2003/08
no abstracts in English
JAERI-Review 2002-022, 149 Pages, 2002/11
no abstracts in English
Hiratsuka, Hajime; Ichige, Hisashi; Kizu, Kaname; Honda, Masao; Miya, Naoyuki
JAERI-Tech 2002-076, 37 Pages, 2002/10
no abstracts in English
Kizu, Kaname; Hiratsuka, Hajime; Miyo, Yasuhiko; Ichige, Hisashi; Sasajima, Tadayuki; Nishiyama, Tomokazu; Masaki, Kei; Honda, Masao; Miya, Naoyuki; Hosogane, Nobuyuki
Fusion Science and Technology (JT-60 Special Issue), 42(2-3), p.396 - 409, 2002/09
Designs and operations of the gas system and pellet injection systems for JT-60 were described. A gas injection valve that is a key component of the gas injection system was developed using a multi layer piezoelectric element. The maximum flow rate of this system is 43.3 Pam3/s. The valve has mechanism for adjustment at atmospheric side meaning that a repair and an adjustment can be conducted without ventilation inside a vacuum vessel. Two systems of pellet injector; one is pneumatic drive and another is centrifugal one were developed. The pneumatic type attained a pellet velocity of 2.3 km/s, which was the world record at the time in 1988. On the other hand, the centrifugal one was developed in 1998. This injector can eject trains of up to 40 cubic (2.1 mm)3 pellets at frequencies of 1~10 Hz and speed of 0.1~1.0 km/s. A guide tube for a magnetic high field side top injection HFS(top)) was also developed in 1999. The pellet injection experiment with the HFS system started in 2000. In addition, another guide tube for HFS(mid) injection was newly developed and installed in March 2001.