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Tateishi, Ryo*; Shimada, Koji; Shimizu, Mayuko; Ueki, Tadamasa*; Niwa, Masakazu; Sueoka, Shigeru; Ishimaru, Tsuneari
Oyo Chishitsu, 62(2), p.104 - 112, 2021/06
We attempted to discriminate between active and non-active faults by linear discriminant analysis using the chemical composition data of fault gouges in Japan, and then examined the elements that represent the difference between them and better discriminants. As a result, the multiple discriminants obtained could discriminate between them with high probability. In addition, the generalization performance of these discriminants is discussed, and the discriminants that can be expected to have high discriminant performance for unknown samples are presented. Also, from the combination of elements common to these discriminants, we narrowed down the number of elements that represent the difference between active and non-active faults to 6, and showed that the combination of TiO
and Sr contributing the most to the discrimination. The method applied in this study is an innovative one that can discriminate the activity by chemical analysis of fault rocks that are universally present in the bedrock.
Ito, Hiroto*; Shiotsu, Hiroyuki; Tanaka, Yoichi*; Nishihara, Satomichi*; Sugiyama, Tomoyuki; Maruyama, Yu
JAEA-Data/Code 2018-012, 42 Pages, 2018/10
JAEA-Data-Code-2018-012.pdf:4.93MB
Chemical composition of fission products transported in nuclear facilities in severe accidents is controlled by slower chemical reaction rates, therefore, it could be different from that evaluated on the chemical equilibrium assumption. Hence, it is necessary to evaluate the chemical composition with reaction kinetics. On the other hand, databases applicable to the analysis of nuclear facilities have not been constructed because knowledge of reaction rates of complex chemical reactions in severe accidents is currently limited. Accordingly, we have developed the CHEMKEq code based on a partial mixed model with chemical equilibrium and reaction kinetics to decrease uncertainties of the chemical composition caused by the reaction rate. The CHEMKEq code, under mass conservation law, firstly evaluates chemical species obeying the chemical equilibrium model, and then, relatively slow reactions are solved by the reaction kinetics model. Moreover, the CHEMKEq code has a multiplicity of use in evaluations of chemical composition because general chemical equilibrium and reaction kinetics models are also available and databases required to calculation are external file formats. This report is the user's guide of the CHEMKEq code, showing models, solution methods, structure of the code and calculation examples. And information to run the CHEMKEq code is summarized in appendixes.
Sakai, Toshihiro
JAEA-Data/Code 2018-006, 75 Pages, 2018/07
JAEA-Data-Code-2018-006.pdf:2.9MB
JAEA-Data-Code-2018-006-appendix(CD-ROM).zip:0.87MB
Data of bulk chemical compositions (major elements and trace elements) and/or of modal compositions of the Toki granitic body are compiled as a data-base for the purpose of improving geological and petrological basic information of the Mizunami Underground Research Laboratory Project and the Regional Hydrogeological Study Project. 696 rock samples are collected from the outcrops and boreholes of the Regional Hydrogeological Study Project, and 636 rock samples are collected from the Mizunami Underground Research Laboratory Construction Site. The analysis data of rock samples, as granitic rock samples, intrusive rock samples and crack filling samples, are attached three-dimensional position information to each thesis and report.
Yamaguchi, Tetsuji; Minase, Naofumi; Iida, Yoshihisa; Tanaka, Tadao; Nakayama, Shinichi
JAERI-Conf 2005-007, p.150 - 155, 2005/08
no abstracts in English
Kameo, Yutaka; Haraga, Tomoko; Nakashio, Nobuyuki; Hoshi, Akiko; Nakashima, Mikio
Nihon Genshiryoku Gakkai Wabun Rombunshi, 3(4), p.354 - 362, 2004/12
In order to investigate chemical stability of solidified products made from Low Level Radioactive Wastes (LLW) by plasma melting, a leaching test based on the MCC (Material Characterization Center)-3S Agitated Powder Leach Test Method was performed to determine Normalized Elemental Mass Loss (NL
) of both main components (Na, Al, Si, Ca, and Fe) of the solidified product and radioactive tracers (
Co, 
Cs, and 
Eu) incorporated into it. The results of leaching test indicated that NLi value was greatly affected by basicity defined as weight ratio of CaO to SiO in the solidified product, while effect of FeO concentration on NL value was small. In the case of basicity less than 0.8, logarithm of NL linearly increased with the basicity, implying that NL value can be estimated by chemical composition of the solidified products.
Nakashio, Nobuyuki; Nakashima, Mikio; Hirabayashi, Takakuni*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 3(3), p.279 - 287, 2004/09
Large-scale melting tests of simulated miscellaneous solid wastes were conducted to characterize solidified products (50L-drum size). Two heating modes were adopted in the tests: hybrid heating and induction heating modes. In the former, wastes were heated with both an induction furnace and a plasma torch, and in the latter, an electrically-conductive crucible was used with the induction furnace. Visual observation, chemical analysis and radioactivity measurements were conducted to the solidified products. It was found that the radioisotope distribution of solidified products was almost homogeneous. There was no remarkable deterioration in the solidified products subsequent to the leaching test.
Nakashio, Nobuyuki; Nakashima, Mikio
Dekomisshoningu Giho, (26), p.45 - 55, 2002/11
Melting treatment of low-level radioactive wastes (LLW) is considered to be a promising technology for the preparation of a stable solid that will be disposed of in near surface repositories. This is because of large reduction of waste volume and production of a stable homogeneous solidified product. In the Japan Atomic Energy Research Institute (JAERI), the construction of the Waste Volume Reduction Facilities (WVRF) has been in progress since 1999. In advance of operation of the WVRF, we have been conducting melting tests of non-metallic solid wastes with the aim of establishing the optimum melting condition for preparation of a stable solid that is suitable for disposal. We have reviewed a part of the melting test conducted in our program.
; ; Ohno, Shuji;
JNC TN9400 2000-092, 247 Pages, 2000/08
JNC-TN9400-2000-092.pdf:20.29MB
Small-scale sodium pool combustion tests Run-F7-3 and Run-F8-1 were performed to investigate the corrosion of floor liner under high moisture condition. ln the both tests, which were performed using the 3m
FRAT-1 vessel at the SAPFIRE facility, the sodium of 507deg-C was leaked on the carbon steel catch pan about for 25 minutes with the flow rate of around 25 kg/h. The air in the vessel was ventilated with the flow rate of 5m/min containing the moisture of 25000-28000 vol.ppm. The duration of combustion was different in two tests by changing the starting time of argon gas injection into the vessel. As the results of post-test analysis such as observation of catch pan surface and chemical analysis of the deposits, it was confirmed that 'Na-Fe double oxidization type corrosion' was dominant in the both tests and that the catch pan and deposits were not under the condition leading to the occurrence of 'molten salt type corrosion.'
; ; ; ;
JNC TN9400 2000-066, 52 Pages, 2000/06
JNC-TN9400-2000-066.pdf:1.82MB
Phase I of feasibility studies on commercialized fast reactor system is being peformed for two years from Japanese Fiscal Year 1999. In this report, results of the study on fluid fuel reactors (especialiy a molten salt fast breeder reactor concept) are described from the viewpoint of technical and economical concerns of the plant system design. ln JFY1999, we have started to investigate the fluid fuel reactors as alternative concepts of sodium cooled FBR systems with MOX fuel, and selected the unique concept of a molten chloride fast, breeder reactor, whose U-Pu fuel cycle can be related to both light water reactors and fast breeder reactors on the basis of present technical data and design experiences. We selected a preliminary composition of molten fuel and conceptual plant design through evaluation of technical and economical issues essential for the molten salt reactors and then compared them with reference design concepts of sodium cooled FBR systems under limited information on the molten chloride fast breeder reactors. The following results were obtained. (1)The molten chloride fast breeder reactors have inherent safety features in the core and plant performances, ad the fluid fuel is quite promising for cost reduction of the fuel fabrication and reprocessing. (2)On the other hand, the inventory of the molten chloride fuel becomes high and thermal conductivity of the coolant is inferior compared to those of sodium cooled FBR systems, then, the size of main components such as lHX's becomes larger and the amount of construction materials is seems to be increased. (3)Furthermore economical vessel and piping materials which contact with the molten chloride salts are required to be developed. From the results, it is concluded that further steps to investigate the molten chloride fast breeder reactor concepts are too early to be conducted.
; *; Tokizawa, Takayuki; *
JNC TY6400 2000-013, 102 Pages, 2000/02
JNC-TY6400-2000-013.pdf:2.45MB
None
Mihara, Morihiro; ; Ueta, Shinzo*; *
JNC TN8430 99-011, 27 Pages, 1999/11
In radioactive waste disposal, compacted Na-bentonite has been proposed for a buffer material. However, Na-bentonite would change to Ca-bentonite in the long term period. The change of Na-bentonite to Ca-bentonite might cause the change in the data concerning with nuclides migration properties such as permeability, sorption and diffusion. In this study, effective diffusion coefficients of HTO, Cs, I and C in compacted Ca-bentonite which was changed from Na-bentonite, Kunigel V1, were obtained and were compared to published those of Kunigel V1. In addition, effective diffusion coefficients for compacted Ca-bentonite with syncetic sea system water, SW, were obtained in order to investigate effect of solution composition. The magnitude of effective diffusion coefficients in Ca-bentonite are arranged in smaller order as Cs
HTO
IC. It is estimated that their effective diffusion coefficients are same those of Na-bentonite. About effect of solution composition, effective diffusion coefficients of HTO in 1.8g/cm dry density with SW were almost same values with distilled system water, DW. However, effective diffusion coefficients of HTO in lower density were smaller than values with DW. Regarding as effective diffusion coefficients of Cs in 1.8g/cm dry density, the effect of SW could not be observed as well as HTO. However, effective diffusion coefficients of I and C existing as an anion in pore water of bentonite increased by the reduction in the ion exclusion.
Kawada, Koji; Ohno, Shuji; Miyake, Osamu; ; ; Tanabe, Hiromi
PNC TN9410 97-036, 243 Pages, 1997/01
As a part of the work for investigating the sodium leak accident which occurred in Monju on December 8, 1995, three tests, (1)sodium leak test, (2)sodium leak and fire test-I, and (3)sodium leak and fire test-II, were carried out at OEC/PNC. Main objectives of these tests are to confirm leak and burning behavior of sodium from the damaged thermometer, and effects of the sodium fire on integrity of the surrounding structure, etc. This report describes the result of the sodium fire test-I carried out as a preliminary test. The test was performed using SOLFA-2 (Sodium Leak, Fire and Aerosol) facility on April 8, 1996. In this test, sodium heated to 480
C was leaked for approximately 1.5 hours from a leak simulated apparatus and caused to drop onto a ventilation duct and a grating with the same dimensions and layout as those in Monju. The main conclusions obtained from the test are shown as below. (1)Observation from video cameras in the test revealed that in early stages of sodium leak, sodium dropped down out of the flexible tube of thermometer in drips. This dripping and burning were expanded in range as sodium splashed on the duct. (2)No damage to the duct itself was detected. However, the aluminum louver frame of the ventilation duct's lower inlet was damaged: Its machine screws had come off, leaving half of the grill (on the grating side) detached. (3)No large hole, like one seen at Monju, were found when the grating was removed from the testing system for inspection, although the area centered on the point that the sodium attacked was damaged in a way indicating the first stages of grating failure: The 5-mm- square lattice was corroded through in some parts, and many blades (originally 3.2 mm thick) had become like the blade of a sharp knife. (4)The burning pan underside thermocouple near the leak point measured 700C in roughly 10 minutes, and for the next hour remained stable between 740C and 770C. There was a ...
Cho, Hisashi*; Yokoi, Koichi*; Noguchi, Yoshifumi*; Morita, Masaya*; Nakamura, Naoaki*; Takahara, Hiroyuki*; Moriya, Toshifumi*
PNC TJ1380 94-001, 1308 Pages, 1994/03
None
Suzuki, Masahide; Hamada, Shozo; P.J.Maziasz*; Jitsukawa, Shiro; Hishinuma, Akimichi
Journal of Nuclear Materials, 191-194, p.1351 - 1355, 1992/00
Times Cited Count：13 Percentile：74.78(Materials Science, Multidisciplinary)no abstracts in English
Tateishi, Ryo*; Shimada, Koji; Shimizu, Mayuko; Sueoka, Shigeru; Niwa, Masakazu; Ishimaru, Tsuneari
no journal, ,
The identification of active faults is based on the displacement and deformation of the current topography and the late Quaternary strata. However, in the absence of them, it is difficult to determine the fault activity. To solve this problem, multivariate analysis was performed using chemical composition data of fault gouges of active and inactive faults in Japan. We performed linear discriminant analysis with a following combination of elements; (a) 11 elements selected by AIC, (b) 8 elements with p-value between 0 and 0.01, (c) 6 elements with p-value between 0 and 0.001. The discrimination rate between active faults and inactive faults is 100% in (a), (b) and 97% in (c). Among elements that represent the difference, TiO and PO
, and AlO
and Rb are considered important, including their respective combinations. These results contribute to clarify the mechanism that creates the difference in chemical composition between active and inactive faults.
