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Nakajima, Nobuya; Takahashi, Hiroki; Kusunoki, Tsuyoshi; Mitomo, Nobuo
JAERI-Tech 2005-057, 54 Pages, 2005/09
JAERI-Tech-2005-057.pdf:4.27MB
Availability using small reactor sited in deep underground cave was examined as a district heat supply system.From the viewpoint of a social acceptability, the contact points with a distributed small reactor system were examined to resolve a social structure-subject of a big city through investigation of the city environmental issue and city calamity. In order to estimate the scale of the heat source of a district heat supply system, a virtual city model was set up about 100,000 populations. It became clear that the heat can be supplied by installing two reactors with thermal-power 100MWt (MR-100G) in caves. Moreover, it turns out that the system will also function effectively for more than 40 years. The economic efficiency of this system was compared with the natural-gas boiler, and we confirmed that the district heat supply system by the small reactor is excellent especially for the case of long-term system operation.
Sasajima, Tadayuki; Yagyu, Junichi; Miyo, Yasuhiko; Miya, Naoyuki; Sakakibara, Satoru*
KEK Proceedings 2003-16 (CD-ROM), 4 Pages, 2004/02
no abstracts in English
Tanai, Kenji; Horita, M.*; Dewa, Katsuyuki*; Goke, Mitsuo*
JNC TN8410 2001-026, 116 Pages, 2002/03
JNC-TN8410-2001-026.pdf:9.19MB
Earthquake resistance for the underground structure is higher than the ground structure. Therefore, the case of examining the earthquake resistance of underground structure was little. However, it carries out the research on the aseismic designing method of underground structure, since the tunnel was struck by Hyogo-ken Nanbu Earthquake, and it has obtained a much knowledge. However, an object of the most study was behavior at earthquake of the comparatively shallow underground structure in the alluvial plain board, and it not carry out the examination on behavior at earthquake of underground structure in the deep rock mass. In the meantime, underground disposal facility of the high level radioactive waste constructs in the deep underground, and it carries out the operation in these tunnels. In addition, it has made almost the general process of including from the construction start to the backfilling to be about 60 years (Japan Nuclear Fuel Cycle Development Institute, 1999). During these periods, it is necessary to also consider the earthquake resistance as underground structure from the viewpoint of the safety of facilities. Then, it extracted future problem as one of the improvement of the basis information for the decision of the safety standard and guideline of the country on earthquake-resistant design of the underground disposal facility, while it carried out investigation and arrangement of earthquake-resistant design cases, guidelines and analysis method on existing underground structure, etc.. And, the research item for the earthquake resistance assessment of underground structure as case study of the underground research laboratory.
; ; Yamazaki, Toshihiko; ; ; Kondo, Toshinari*; *
JNC TN8400 2001-030, 99 Pages, 2002/01
JNC-TN8400-2001-030.pdf:13.24MB
There is a great deal of that we build a Base-Isolated building with the quaternary deposit ground. In an atomic energy institution, a study request is strong. When we build a Base-Isolated building with the quaternary deposit ground, evaluation of earthquake vibration of a vertical direction is an important problem. In an atomic energy institution, we design it by big earthquake load, and therefore examination is necessary. And, in this study, we do examination to build a Base-Isolated building with the quaternary deposit ground, we report it about an evaluation method of a design. Furthermore, we report that we estimated pipe laying and machinery to put in a building of Base-lsolated.
JNC TN1400 2001-015, 509 Pages, 2001/10
JNC-TN1400-2001-015.pdf:25.67MB
no abstracts in English
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JNC TN9400 2000-060, 168 Pages, 2000/05
JNC-TN9400-2000-060.pdf:4.09MB
Optimal vertical isolation characteristics were studied for the structural concept of vertical seismic isolation system, which uses a common deck and a set of large coned dish springs. Four kinds of earthquake wave and three kinds of artificial seismic wave were used. The earthquake response analysis of a base isolated building was carried out considering some ground conditions and some vertical vibration characteristics of the building isolator. Floor response and acceleration time history at the vertical isolation level were arranged. Using the acceleration time history as a seismic input, the earthquake response analysis of the vertical isolation system according to single degree of freedom model was carried out. Linear analysis and non-linear analysis were made. ln the linear analysis, vertical isolation frequency was examined within 0.8 to 2.5 Hz, and damping ratio was examined within 2 to 60%. ln the non-linear analysis, it was examined within vertical isolation frequency 0.5 to 5Hz, which depended only on the rigidity of the coned disk spring, rigidity ratio of the damping devise 1 to 20 and yield seismic intensity of the damping devise 0.01 to 0.2. As the optimal vertical isolation characteristics of the system, the criterion of largest relative displacement, maximum acceleration and maximum value of the floor response acceleration between 5 to 12Hz was set, the combination region of the appropriate parameter were examined. ln case of largest relative displacement 50mm, acceleration response magnification of 0.75, floor response magnification of 0.33 were used as a criterion, from the result of the linear analysis, vertical frequency was set at 0.8 to l.2 Hz, and by combining the damping ratio over 20 %, it was proven that appropriate vertical isolation characteristics were obtained. The result of the non-linear analysis showed that the combination of the coned disk spring of vertical frequency 0.8 to 1.0 Hz and the damping element of rigidity ...
*; *
JNC TN9200 2000-001, 133 Pages, 2000/02
The 11th Meeting for Reporting Safety Research on FBR and ATR was held at the exhibition hall (TECHNO O-ARAI) in OEC on the 15th of December in 1999. The reports of each subject in FY1996-1998 were presented before discussion at this meeting. The 11 subjects had been selected from the subjects (34 in total) on power reactor in fast breeder reactor, earthquake-proof and probabilistic safety assessment according to the decisions of sub-meetings in Sectional Meeting of Safety Research. This meeting was open to the public, and large attendance outside of JNC was invited for the purpose of getting some advice from related specialists. This report contains presentation papers, questions and answers, list of attendance, etc. Refer to the JNC open report for detailed results of safety research in FY1996-1998.
Takachi, Kazuhiko; Taniguchi, Wataru
JNC TN8400 99-042, 68 Pages, 1999/11
The buffer material is expected to maintain its low water permeability, self-sealing properties, radionuclides adsorption and retardation properties, thermal conductivity, chemical buffering properties, overpack supporting properties, stress buffering properties, etc. over a long period of time. Natural clay is mentioned as a material that can relatively satisfy above. Among the kinds of natural clay, bentonite when compacted is superior because (1)it has exceptionally low water permeability and properties to control the movement of water in buffer, (2)it fills void spaces in the buffer and fractures in the host rock as it swells upon water uptake, (3)it has the ability to exchange cations and to adsorb cationic radioelements. In order to confirm these functions for the purpose of safety assessment, it is necessary to evaluate buffer properties through laboratory tests and engineering-scale tests, and to make assessments based on the ranges in the data obtained. This report describes the procedures, test conditions, results and examinations on the buffer material of dynamic triaxial tests, measurement of elastic wave velocity and liquefaction tests that aim at getting hold of dynamic mechanical properties. MWe can get hold of dependency on the shearing strain of the shearing modulus and hysteresis damping constant, the application for the mechanical model etc. by dynamic triaxial tests, the acceptability of maximum shearing modulus obtained from dynamic triaxial tests etc. by measurement of elastic wave velocity and dynamic strength caused by cyclic stress etc. by liquefaction tests.
JNC TN9400 99-041, 187 Pages, 1999/05
lt is widely recognized that the current seismic design methods for piping involve a large amount of safety margin. From this viewpoint, a series of seismic analyses and evaluations with various design codes were made on typical LMFBR main sodium piping systems. Actual capability against seismic loads were also estimated on the piping systems. Margins contained in the current codes were quantified based on these results, and potential benefits and impacts to the piping seismic design were assessed on possible mitigation of the current code allowables. From the study, the following points were clarified; (1)A combination of inelastic time history analysis and true(without margin) strength capability allows several to twenty times as large seismic load compared with the allowable load with the current methods. (2)The new rule of the ASME is relatively compatible with the results of inelastic analysis evaluation. Hence, this new rule might be a goal for the mitigation of seismic design rule. (3)With this mitigation, seismic design accommodation such as equipping with a large number of seismic supports may become unnecessary.
; ; Shimizu, Kazuhiko; Miyahara, Kaname; ; Hasegawa, Hiroshi; Iwasa, Kengo
JNC TN1400 99-008, 656 Pages, 1999/04
None
Mori, Koji*; Neyama, Atsushi*; *; Nishimura, Kazuya*
PNC TJ1458 97-003, 179 Pages, 1997/02
None
Hayashi, Hideyuki; ;
PNC TN9410 96-062, 186 Pages, 1996/02
A conceptual design study on a 1300MWe large FBR plant was performed with focusing on enhancing passive safety and capital cost reduction. Spectrum-adjusted mixed nitride fueled core in which zirconium hydride was added, was applied to enlarge Doppler reactivity coefficient. Breeding ratio of 1.2 was obtained only with one layer of radial blanket subassemblies by optimizing the content of the zirconium hydride. The optimization also lightened the burden to the reactor structure through the reduction of the core diameter. Reactor passive shutdown were performed in the ATWS events of ULOF and ULOHS, and UTOP caused by one control rod full runout was endurable under the criterion of the prevention of coolant boiling. The safety feature can be called as inherent safety, because the feature comes only from the reactivity characteristics of the core. The integrities of the reactor structures which characterize head-access loop type reactor were evaluated on the transient thermal stress at the loss of flow accident and on seismic strain. Vertical strain of core support plate at loss of flow condition was also evaluated on the passive shutdown at ULOF. The capital cost of the large FBR plant was estimated 1.3 to 1.4 times as high as that of the same scale LWR based on the weight of major components.