Determination of regional stress state for estimating local stress state (Contract research)

Mizuta, Yoshiaki*; Kaneko, Katsuhiko*; Matsuki, Koji*; Sugawara, Katsuhiko*; Sudo, Shigeaki*; Hirano, Toru; Tanno, Takeo; Matsui, Hiroya

JAEA-Research 2010-011, 35 Pages, 2010/06

JAEA-Research-2010-011.pdf:4.42MB

The best way to know the initial stress clearly is to measure it in the location where a tunnel will be excavated. However, it is difficult to measure a large number of the initial stresses, budgetary considerations notwithstanding, because of the large scale of underground structures like a radioactive waste disposal facility. Therefore we developed a method for determination of initial stress for arbitrary points from limited results of initial stress measurements. This report is a summary of the contract work about this development. At first, we made local scale numerical models of the Tono area. Using these models, we determined the regional stress state from limited initial stress measurements results. Then we applied the regional stress state to boundary conditions of other numerical models and estimated initial stress at arbitrary points. The result is an estimated initial stress that matched the original stress measurement results from the first analytical results.

Study on Configuration and Structure of Faults

Sugawara, Masaaki*; Maruyama, Toru*; Kambara, Hiroshi*

JNC TJ7420 2005-047, 79 Pages, 2003/03

JNC-TJ7420-2005-047.pdf:12.71MB

Configuration and structure of the ore veins of the Toyoha mine, which occur in faults, were studied with the purpose of developing methods for investigating the effect of fault movement to groundwater flow. Information on the shape of the veins were acquired and analyzed. Plane vein maps in some levels and cross sections of four representative vein systems (Tajima-Harima, Izumo-Shinano, Soya, Sorachi) of the Toyoha ore deposit were scanned, and three-dimensional features of vein distributions were recorded as image data. Morphological characteristics of typical veins of the Toyoha ore deposit were extracted from vein maps, geological and mineralogical cross sections and vein sketches. A tendency of vein-shape changes is recognized from the upper to the lower parts; cymoid curve with strong lensing, gentle cymoid curve with relatively constant width, linear vein with relatively constant width in ascending order of depth. This is thought to be a morphological characteristics of shear fracture formed in correspondence with increase of confining pressure. Distribution of vein trace length of the Toyoha mine exist within the range of uncertainty in the figure between fracture trace length and cumulative number of fractures indicated by Ohtsu (2001). Thus, accumulated number of fracture trace length is thought to be in linear relation irrespective of size, region and rock ype.

None

; ; ; ; Kobayashi, Tetsuro*; ; Sugawara, Satoru; Matsumoto, Mitsuo

Donen Giho, (94), p.36 - 52, 1995/06

https://jopss.jaea.go.jp/pdfdata/PNC-TN1340-95-002.pdf

None

Investigation of preventive measures of gas entrainment phenomena for large scale FBR; Investigation on Baffle ring and porous-type UIS

; ; Yamaguchi, Akira; ; ; Sugawara, Satoru

PNC TN9410 92-352, 62 Pages, 1992/11

PNC-TN9410-92-352.pdf:2.3MB

In-vessel thermohydraulic analysis with multi-dimensional code AQUA was conducted to investigate efficiency of a baffle ring and of a porous-type UIS (upper instrumentation structure) for preventation of gas entrainment to coolant from gas plenum of reactor vessel. Through the analysis using the AQUA code and the discussion based on their results, the following results have been obtained: [Baffle Ring Equipment] (1)In order to reduce maximum surface verocity, the effect with the width 40 cm of the baffle ring equipment better than the width 20 cm. (2)Maximum surface velocity is 40 cm/s using the baffle ring equipment of width 40 cm. [Porous-type UIS] (1)Effective mass flow ratio of the UIS porous to the UIS skirt is 50 % to decrease maximum surface velocity. (2)Maximum surface velocity is 52 cm/s using the porous-type UIS with the above mass flow distribution. Furthermore analysis with the AQUA code were carried out for the conbined condition of the baffle rings with 40 cm width and the porous-type UIS with the condition of the effective mass flow ratio 50 %. Maximum surface velocity 0.33 m/s closer to the MONJU condition (0.3 m/s) was obtained from the analysis.

Investigation of preventive measure of gas entrainment phenomena for large-scale FBR; Investigation of partially dip plate

Muramatsu, Toshiharu; Murata, Masayuki*; Ieda, Yoshiaki; Yamaguchi, Akira; Nagata, Takashi; Sugawara, Satoru

PNC TN9410 91-318, 48 Pages, 1991/10

PNC-TN9410-91-318.pdf:1.83MB

In-vessel thermohydraulic analysis with multi-purpose three-dimensional code AQUA as conducted for transient simulating a pump coast down and reactor scram (manual reactor trip event) to confirm efficiency of partially dip plate equipments in a large-scale fast breeder reactor. Throught the analysis using the AQUA code and the discussion based on their results, the following results have been obtained: [Sodium Surface Velocity] Maximum surface velocity is 0.33m/s in the condition of D=0.75m and W=1.905m. The velocity is the same as that or the MONJU reactor. [Thermal Stratification] Maximum axial temperature gradient 445C/m was calculated. The gradient is nearly equal to the results in the MONJU reactor. [Main Loop Temperature Transient] Maximum temperature transients at the outlet nozzle of reactor vessel was -0.51C/s. [Circumferential Temperature Gradient] Maximum circumferential temperature gradient at the neighborhood of reactor vessel was 67C/m. The gradient is equivalent to five times of that when a partially dip plate is not adopted.

Steam-water void fraction for vertical upflow in a 73.9 mm pipe

Sugawara, Satoru; Beattie, D. R. H.*

International Journal of Multiphase Flow, 12(4), p.641 - 653, 1986/07

https://doi.org/10.1016/0301-9322(86)90065-0

None

Future prospect of nuclear knowledge and information resources

Yonezawa, Minoru; Sugawara, Satoru

no journal, , 

It is necessary to make the most of accumulated nuclear knowledge and information resources for sustainable nuclear research and development (R&D). While importance of Nuclear Knowledge Management (NKM) has been recognized, introduced and applied in nuclear communities, there still remain some issues. The authors extract issues from the standpoint of sharing nuclear knowledge and information resources more efficiently, such as promotion of open access to R&D results, enhancement of International Nuclear Information System (INIS) and transfer of tacit knowledge. Concerning promotion of open access to R&D results, R&D results should be open as much as possible through institutional repository, INIS, etc. Promotion of INIS database and libraries network is required for better nuclear knowledge and information resources sharing. Socialization of tacit knowledge is required and externalization of tacit knowledge to become explicit knowledge is important for transfer of tacit knowledge.