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Journal Articles

3D FEM soil-structure interaction analysis for Kashiwazaki-Kariwa Nuclear Power Plant considering soil separation and sliding

Ichihara, Yoshitaka*; Nakamura, Naohiro*; Moritani, Hiroshi*; Choi, B.; Nishida, Akemi

Frontiers in Built Environment (Internet), 7, p.676408_1 - 676408_14, 2021/06

The objective of this study is the improvement of response evaluations of structures, facilities and equipment in evaluation of three-dimensional seismic behavior of nuclear power plant facilities, by three-dimensional finite element method model, including separation and sliding between the soil and the basement walls. To achieve this, simulation analyses of Kashiwazaki Kariwa nuclear power plant unit 7 reactor building under the 2007 Niigataken-chuetsu-oki earthquake event were carried out. These simulation analyses consider soil-structure interaction using a three-dimensional finite element method model in which the soil and building are three-dimensionally modeled by the finite element method. It is found that basemat uplift is generated on east side of the basemat edge, and this has an important influence on the results. The importance is evidenced by the difference of local response in soil pressure characteristics beneath the edge of basemat, the soil pressure characteristics along the east side of basement wall and the maximum acceleration response at the west end of the embedded surface. Although, in this particular study, basemat uplift, separation and sliding have only a relatively small influence on the maximum acceleration response of embedded surface and the soil pressure characteristics along the basement walls and beneath the basemat, under strong earthquake motion, these influences can be significant, therefore appropriate evaluation of this effect should be considered.

Journal Articles

Early emergency responses of the Japan Atomic Energy Agency against the Fukushima Daiichi Nuclear Power Station Accident in 2011

Okuno, Hiroshi; Sato, Sohei; Kawakami, Takeshi; Yamamoto, Kazuya; Tanaka, Tadao

Journal of Radiation Protection and Research, 46(2), p.66 - 79, 2021/06

The nuclear accident at the Fukushima Daiichi Nuclear Power Station (NPS) of Tokyo Electric Power Company (TEPCO) was a typical one of the disastrous damages that induced evacuation of the residents around the NPS, which was triggered by the hugest earthquake and associated tsunami. This paper summarized early responses of the Japan Atomic Energy Agency (JAEA), especially of its Nuclear Emergency Assistance and Training Center (NEAT) to the off-site emergencies associated with the TEPCO's Fukushima Daiichi NPS. The paper addressed activities of emergency preparedness of the NEAT before 2011 in relevant to the TEPCO's Fukushima Daiichi NPS, the situation of the NEAT on March 11, 2011, and its early responses to the related off-site emergencies including those caused by the accident at the TEPCO's Fukushima Daiichi NPS. The paper also discussed issues associated with complex disasters.

JAEA Reports

Earthquake observation data collection in the Horonobe Underground Research Laboratory Project (Phase II)

Miyara, Nobukatsu; Matsuoka, Toshiyuki

JAEA-Data/Code 2019-013, 8 Pages, 2020/01

JAEA-Data-Code-2019-013.pdf:1.45MB
JAEA-Data-Code-2019-013-appendix(DVD-ROM)1.zip:239.91MB
JAEA-Data-Code-2019-013-appendix(DVD-ROM)10.zip:346.69MB
JAEA-Data-Code-2019-013-appendix(DVD-ROM)11.zip:237.95MB
JAEA-Data-Code-2019-013-appendix(DVD-ROM)12.zip:335.05MB
JAEA-Data-Code-2019-013-appendix(DVD-ROM)13.zip:335.0MB
JAEA-Data-Code-2019-013-appendix(DVD-ROM)2.zip:433.26MB
JAEA-Data-Code-2019-013-appendix(DVD-ROM)3.zip:360.88MB
JAEA-Data-Code-2019-013-appendix(DVD-ROM)4.zip:292.24MB
JAEA-Data-Code-2019-013-appendix(DVD-ROM)5.zip:315.31MB
JAEA-Data-Code-2019-013-appendix(DVD-ROM)6.zip:426.42MB
JAEA-Data-Code-2019-013-appendix(DVD-ROM)7.zip:286.49MB
JAEA-Data-Code-2019-013-appendix(DVD-ROM)8.zip:187.61MB
JAEA-Data-Code-2019-013-appendix(DVD-ROM)9.zip:826.1MB

As part of the research and development program on the geological disposal of high-level radioactive waste (HLW), the Horonobe Underground Research Center, a division of the Japan Atomic Energy Agency (JAEA), is implementing the Horonobe Underground Research Laboratory Project (Horonobe URL Project) with the aim at investigating sedimentary rock formations. This data collection is a compilation of Earthquake observation data acquired in the Horonobe Underground Research Project (Phase II).

Journal Articles

Status of rock dynamics study in Horonobe Underground Research Laboratory, Japan

Sato, Toshinori; Aoyagi, Kazuhei; Matsuzaki, Yoshiteru; Miyara, Nobukatsu; Miyakawa, Kazuya

Rock Dynamics; Experiments, Theories and Applications, p.575 - 580, 2018/06

Rock dynamics is one of key issue for research and development of techniques for safe geological disposal of high-level radioactive waste. Horonobe Underground Research Laboratory (URL) is off-site URL constructed in soft sedimentary rock to the depth of 350m with three shafts and three level experimental galleries. Earthquake-resistant design of underground openings, observation of seismic records and groundwater pressure change due to earthquakes, and excavation disturbed zone experiment have been performed relating to the study of rock dynamics in URL project. This paper shows current status of Horonobe URL project and results of earthquake-resistant design of shafts, observation of seismic records and groundwater pressure change due to the 2011 off the Pacific coast of Tohoku Earthquake.

Journal Articles

Engineering applications using probabilistic aftershock hazard analyses; Aftershock hazard map and load combination of aftershocks and tsunamis

Choi, B.; Nishida, Akemi; Itoi, Tatsuya*; Takada, Tsuyoshi*

Geosciences (Internet), 8(1), p.1_1 - 1_22, 2018/01

After the Tohoku earthquake in 2011, we observed that aftershocks tended to occur in a wide region after such a large earthquake. These aftershocks resulted in secondary damage or delayed rescue and recovery activities. However, it is difficult to evaluate the hazards of an aftershock before the main shock due to various uncertainties. For possible great earthquakes, we must make decisions based on such uncertainties, and it is important to quantify the various uncertainties. We previously proposed a probabilistic aftershock occurrence model that is expected to be useful to develop plans for recovery activities after future large earthquakes. In this paper, engineering applications of the proposed approach for probabilistic aftershock hazard analysis are shown for demonstration purposes. One application is to use aftershock hazard maps to plan recovery activities. Another application is to derive load combination equations of the load and resistance factor design (LRFD) considering the simultaneous occurrence of tsunamis and aftershocks for the tsunami-resistant design of tsunami evacuation buildings and nuclear facilities.

JAEA Reports

Scenario development on application of engineering technology for geological disposal; Study of influence of earthquake at site construction, operation and closure stages and that impact on safety functions after closure of disposal facility (Contract research)

Takai, Shizuka; Takayama, Hideki*; Takeda, Seiji

JAEA-Data/Code 2016-020, 40 Pages, 2017/03

JAEA-Data-Code-2016-020.pdf:2.42MB

In this report, another group of scenarios for occurrence of earthquake at construction stage, operation stage and closure stage of disposal facility was presented. At first, we compiled information about damage cases of tunnel by earthquake and analyzed conditions for occurrence of damage. Base on this result and the previous report, information of influence of the accidents and human factors on safety functions and information of FEP about THMC variation, we specified events to be considered, which occur by earthquake and influence engineering barriers, natural barriers and long-term safety after closure stage of disposal facility. We compiled influence of the events on safety functions after closure stage of disposal and showed the chains of the influence on long-term safety as scenarios. These results were integrated as a database that could support development of scenarios caused by application of engineering technologies to geological disposal.

Journal Articles

Confirmation of seismic integrity of HTTR against 2011 Great East Japan Earthquake

Ono, Masato; Iigaki, Kazuhiko; Shimazaki, Yosuke; Shimizu, Atsushi; Inoi, Hiroyuki; Tochio, Daisuke; Hamamoto, Shimpei; Nishihara, Tetsuo; Takada, Shoji; Sawa, Kazuhiro; et al.

Proceedings of 24th International Conference on Nuclear Engineering (ICONE-24) (DVD-ROM), 12 Pages, 2016/06

On March 11th, 2011, the Great East Japan Earthquake of magnitude 9.0 occurred. When the great earthquake occurred, the HTTR had been stopped under the periodic inspection and maintenance of equipment and instrument. In the great earthquake, the maximum seismic acceleration observed at the HTTR exceeded the maximum value in seismic design. The visual inspection of HTTR facility was carried out for the seismic integrity conformation of HTTR. The seismic analysis was also carried out using the observed earthquake motion at HTTR site to confirm the integrity of HTTR. The concept of comprehensive integrity evaluation for the HTTR facility is divided into two parts. One is the inspection of equipment and instrument. The other is the seismic response analysis using the observed earthquake. For the basic inspections of equipment and instrument were performed for all them related to the operation of reactor. The integrity of the facilities is confirmed by comparing the inspection results or the numerical results with their evaluation criteria. As the result of inspection of equipment and instrument and seismic response analysis, it was judged that there was no problem to operate the reactor, because there was no damage and performance deterioration, which affects the reactor operation. The integrity of HTTR was also supported by the several operations without reactor power in cold conditions of HTTR in 2011, 2013 and 2015.

Journal Articles

Evaluation on seismic integrity of HTTR core components

Ono, Masato; Iigaki, Kazuhiko; Shimazaki, Yosuke; Tochio, Daisuke; Shimizu, Atsushi; Inoi, Hiroyuki; Hamamoto, Shimpei; Takada, Shoji; Sawa, Kazuhiro

Proceedings of International Topical Meeting on Research Reactor Fuel Management and Meeting of the International Group on Reactor Research (RRFM/IGORR 2016) (Internet), p.363 - 371, 2016/03

HTTR is graphite moderated and helium gas-cooled reactor with prismatic fuel elements and hexagonal blocks. Here, the graphite block is brittle materials and might be damaged by collision of neighboring blocks by the large earthquake. A seismic observation system is installed in the HTTR site to confirm a behavior of a seismic event. On March 11th, 2011, off the Pacific coast of Tohoku Earthquake of magnitude 9.0 occurred. After the accident at the TEPCO Fukushima Daiichi Nuclear Power Station, the safety of nuclear reactors is the highest importance. To confirm the seismic integrity of HTTR core components, the seismic analysis was carried out using the evaluation waves based on the relationship between the observed earthquake motion at HTTR site and frequency transfer function. In parallel, confirmation tests of primary cooling system on cold state and integrity confirmation of reactor buildings and component support structures were also carried out. As a result, it was found that a stress value of the graphite blocks satisfied an allowable value, and the integrity of the HTTR core components was ensured. The integrity of HTTR core components was also supported by the operation without reactor power in cold conditions of HTTR. The obtained data was compared with the normal plant data before the earthquake. As the result, the integrity of the HTTR facilities was confirmed.

JAEA Reports

Study on engineering technologies in the Mizunami Underground Research Laboratory (FY 2014); Development of design and construction planning and countermeasure technologies (Contract research)

Kobayashi, Shinji*; Niimi, Katsuyuki*; Tsuji, Masakuni*; Yamada, Toshiko*; Aoyagi, Yoshiaki; Sato, Toshinori; Mikake, Shinichiro; Osawa, Hideaki

JAEA-Technology 2015-039, 170 Pages, 2016/02

JAEA-Technology-2015-039.pdf:37.73MB

The researches on engineering technology in the Mizunami Underground Research Laboratory (MIU) plan consists of (1) development of design and construction planning technologies, (2) development of construction technology, (3) development of countermeasure technology, (4) development of technology for security, and (5) development of technologies regarding restoration or reversal and mitigating of the excavation effect. To develop design and construction planning technologies, and countermeasure technology, the analysis of measured data during earthquake and seismic movement characteristics at deep underground, and the examination of grouting method were carried out. For the characteristics of earthquake ground motion, measurement data obtained by seismometers installed in the Mizunami Underground Laboratory were analyzed, and the comprehensive assessment of the relationship between the measurement data and the geological condition at each depth was performed. As for "Study on grouting method at deep underground ", post grouting was carried out and evaluated based on the Construction plan in FY2013. Furthermore, target of the future R&D was proposed.

Journal Articles

Development of prediction technology of two-phase flow dynamics under earthquake acceleration, 16; Experimental and numerical study of pressure fluctuation effects on bubble motion

Kato, Yuki; Yoshida, Hiroyuki; Yokoyama, Ryotaro*; Kanagawa, Tetsuya*; Kaneko, Akiko*; Monji, Hideaki*; Abe, Yutaka*

Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 8 Pages, 2015/05

Journal Articles

Development of prediction technology of two-phase flow dynamics under earthquake acceleration

Yoshida, Hiroyuki; Nagatake, Taku; Takase, Kazuyuki; Kaneko, Akiko*; Monji, Hideaki*; Abe, Yutaka*

Mechanical Engineering Journal (Internet), 1(4), p.TEP0025_1 - TEP0025_11, 2014/08

JAEA Reports

Dynamic analysis of ITER tokamak based on results of vibration test using scaled model

Takeda, Nobukazu; Kakudate, Satoshi; Nakahira, Masataka

JAERI-Tech 2004-072, 43 Pages, 2005/01

JAERI-Tech-2004-072.pdf:6.06MB

The vibration experiments of the support structures with flexible plates for the ITER major components such as the vacuum vessel (VV) and the toroidal field (TF) coil were performed aiming to obtain its basic mechanical characteristics. Based on the experimental results, numerical analysis regarding the actual support structure was performed and a simplified model of the support structure was proposed. A support structure was modeled by only two spring elements. The stiffness calculated by the spring model agrees well with that of shell model, simulating actual structures based on the experimental results. It is therefore found that the spring model with the only two values of stiffness enables to simplify the complicated support structure with flexible plates. Using the spring model, the dynamic analysis of the VV and TF coil were performed to estimate the integrity under the design earthquake. As a result, the maximum relative displacement of 8.6 mm between VV and TF coil is much less than designed clearance, 100 mm, so that the integrity of the components is ensured.

Journal Articles

Dynamic analysis of ITER tokamak using simplified model for support structure

Takeda, Nobukazu; Shibanuma, Kiyoshi

Purazuma, Kaku Yugo Gakkai-Shi, 80(11), p.988 - 990, 2004/11

The simplified analytical model of the support structure composed of complicated structures such as multiple flexible plates was proposed for the dynamic analysis of the ITER major components of VV and TF coil. The support structure composed of flexible plates and connection bolts was modeled as a spring model composed of only two spring elements including the effect of connection bolts. The stiffness of both spring models for VV and TF coil agree well with that of shell models simulating actual structures such as flexible plates and connection bolts. Using the proposed model, the dynamic analysis of the VV and TF coil for the ITER were performed to estimate the integrity under the design earthquake at Rokkasho, a candidate of ITER site. As a result, it is found that the maximum relative displacement of 8.6 mm between VV and TF coil is much less than 100 mm, so that the integrity of the major components are ensured for the expected earthquake event.

JAEA Reports

SHEAT for PC: A Computer code for probabilistic seismic hazard analysis for personal computer, user's manual

Yamada, Hiroyuki; Tsutsumi, Hideaki*; Ebisawa, Katsumi*; Suzuki, Masahide

JAERI-Data/Code 2002-001, 161 Pages, 2002/03

JAERI-Data-Code-2002-001.pdf:6.62MB

no abstracts in English

JAEA Reports

R&D on seismic emergency information system

Seismic Emergency Information System Research Team

JAERI-Tech 2001-036, 294 Pages, 2001/06

JAERI-Tech-2001-036.pdf:23.23MB

no abstracts in English

JAEA Reports

Progress of R&D on seismic emergency information system

Seismic Emergency Information System Research Team

JAERI-Tech 2000-063, 143 Pages, 2000/09

JAERI-Tech-2000-063.pdf:7.78MB

no abstracts in English

Journal Articles

Development of methodology for evaluating ground motion parameters and information system under seismic emergency

Shibata, Katsuyuki; Ebisawa, Katsumi; Abe, Ichiro*; Kuno, Tetsuya; Hori, S.*; Oi, Masahiro*

Proceedings of 12th World Conference in Earthquake Engineering (CD-ROM), 8 Pages, 2000/01

no abstracts in English

Journal Articles

Evaluation of aseismic integrity in HTTR core-bottom structure, I; Aseismic test for core-bottom structure

Iyoku, Tatsuo; Futakawa, Masatoshi; Ishihara, Masahiro

Nucl. Eng. Des., 148, p.71 - 81, 1994/00

 Times Cited Count:7 Percentile:57.56(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Coupling effect of core-bottom structure and core graphite blocks in HTTR

Iyoku, Tatsuo; Futakawa, Masatoshi; Shirai, Hiroshi*; Shiozawa, Shusaku; Ishihara, Masahiro; Takikawa, Noboru*

Proc. of the 12th Int. Conf. on Structural Mechanics in Reactor Technology,Vol. K; SMiRT 12, p.97 - 102, 1993/00

no abstracts in English

Journal Articles

Seismic response of the High-Temperature Engineering Test Reactor core bottom structure

Iyoku, Tatsuo; Inagaki, Yoshiyuki; Shiozawa, Shusaku; Futakawa, Masatoshi; *

Nuclear Technology, 99, p.169 - 176, 1992/08

 Times Cited Count:8 Percentile:62.62(Nuclear Science & Technology)

no abstracts in English

36 (Records 1-20 displayed on this page)