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Risk Analysis Research Group, Reactor Safety Research Division, Nuclear Safety Research Center
JAEA-Data/Code 2024-006, 40 Pages, 2024/07
The Risk Analysis Research Group, Reactor Safety Research Division, Nuclear Safety Research Center, Sector of Nuclear Safety Research and Emergency Preparedness, Japan Atomic Energy Agency has been developing OSCAAR, a probabilistic risk assessment program for nuclear facility accidents. OSCAAR has the feature to calculate atmospheric concentrations of radioactive materials using an atmospheric dispersion model. This feature requires the input of meteorological data about wind speed, precipitation rate, atmospheric stability and so on. However, to use numerical weather prediction data created from the Japan Meteorological Agency (JMA) on OSCAAR, it is necessary to convert the data format to match OSCAAR input format in advance. Therefore, we developed GPV2OSC, a pre-processing program for OSCAAR, to create meteorological data converted from JMA weather prediction data format to OSCAAR input format when the target region and period are specified. This report describes the outline and usage of GPV2OSC.
Kubo, Kotaro
Science and Technology of Nuclear Installations, 2023, p.7402217_1 - 7402217_12, 2023/06
Times Cited Count:1 Percentile:41.04(Nuclear Science & Technology)Kubo, Kotaro; Jang, S.*; Takata, Takashi*; Yamaguchi, Akira*
Journal of Nuclear Science and Technology, 60(4), p.359 - 373, 2023/04
Times Cited Count:8 Percentile:83.23(Nuclear Science & Technology)Probabilistic risk assessment (PRA) is an essential approach to improving the safety of nuclear power plants. However, this method includes certain difficulties, such as modeling of combinations of multiple hazards. Seismic-induced flooding scenario includes several core damage sequences, i.e., core damage caused by earthquake, flooding, and combination of earthquake and flooding. The flooding fragility is time-dependent as the flooding water propagates from the water source such as a tank to compartments. Therefore, dynamic PRA should be used to perform a realistic risk analysis and quantification. This study analyzed the risk of seismic-induced flooding events by coupling seismic, flooding, and thermal-hydraulics simulations, considering the dependency between multiple hazards explicitly. For requirements of safety improvement, especially in light of the Fukushima Daiichi Nuclear Power Plant accident, sensitivity analysis was performed on the seismic capacity of systems, and the effectiveness of alternative steam generator injection by a portable pump was estimated. We demonstrate the use of this simulation-based dynamic PRA methodology to evaluate the risk induced by a combination of hazards.
Kubo, Kotaro; Tanaka, Yoichi*; Ishikawa, Jun
Proceedings of the Institution of Mechanical Engineers, Part O; Journal of Risk and Reliability, 11 Pages, 2023/00
Times Cited Count:1 Percentile:33.61(Engineering, Multidisciplinary)Kubo, Kotaro; Jang, S.*; Takata, Takashi*; Yamaguchi, Akira*
Journal of Nuclear Science and Technology, 59(3), p.357 - 367, 2022/03
Times Cited Count:6 Percentile:56.19(Nuclear Science & Technology)Dynamic probabilistic risk assessment (PRA), which handles epistemic and aleatory uncertainties by coupling the thermal-hydraulics simulation and probabilistic sampling, enables a more realistic and detailed analysis than conventional PRA. However, enormous calculation costs are incurred by these improvements. One solution is to select an appropriate sampling method. In this paper, we applied the Monte Carlo, Latin hypercube, grid-point, and quasi-Monte Carlo sampling methods to the dynamic PRA of a station blackout sequence in a boiling water reactor and compared each method. The result indicated that quasi-Monte Carlo sampling method handles the uncertainties most effectively in the assumed scenario.
Yonomoto, Taisuke; Mineo, Hideaki; Murayama, Yoji; Hohara, Shinya*; Nakajima, Ken*; Nakatsuka, Toru; Uesaka, Mitsuru*
Nihon Genshiryoku Gakkai-Shi ATOMO, 63(1), p.73 - 77, 2021/01
no abstracts in English
Nuclear Safety Research Center, Sector of Nuclear Safety Research and Emergency Preparedness
JAEA-Review 2018-022, 201 Pages, 2019/01
Nuclear Safety Research Center (NSRC), Sector of Nuclear Safety Research and Emergency Preparedness, Japan Atomic Energy Agency (JAEA) is conducting technical support to nuclear safety regulation and safety research based on the Mid-Long Term Target determined by Japanese government. This report summarizes the research structure of NSRC and the cooperative research activities with domestic and international organizations as well as the nuclear safety research activities and results in the period from JFY 2015 to 2017 on the nine research fields in NSRC; (1) severe accident analysis, (2) radiation risk analysis, (3) safety of nuclear fuels in light water reactors (LWRs), (4) thermohydraulic behavior under severe accident in LWRs, (5) materials degradation and structural integrity, (6) safety of nuclear fuel cycle facilities, (7) safety management on criticality, (8) safety of radioactive waste management, and (9) nuclear safeguards.
Uchida, Shunsuke; Chimi, Yasuhiro; Kasahara, Shigeki; Hanawa, Satoshi; Okada, Hidetoshi*; Naito, Masanori*; Kojima, Masayoshi*; Kikura, Hiroshige*; Lister, D. H.*
Nuclear Engineering and Design, 341, p.112 - 123, 2019/01
Times Cited Count:7 Percentile:57.46(Nuclear Science & Technology)Improvement of plant reliability based on reliability-centered-maintenance (RCM) is going to be undertaken in NPPs. RCM is supported by risk-based maintenance (RBM). The combination of prediction and inspection is one of the key issues to promote RBM. Early prediction of IGSCC occurrence and its propagation should be confirmed throughout the entire plant systems which should be accomplished by inspections at the target locations followed by timely application of suitable countermeasures. From the inspections, accumulated data will be applied to confirm the accuracy of the code, to tune some uncertainties of the key data for prediction, and then, to increase their accuracy. The synergetic effects of prediction and inspection on application of effective and suitable countermeasures are expected. In the paper, the procedures for the combination of prediction and inspection are introduced.
Saito, Kimiaki; Takahara, Shogo; Uezu, Yasuhiro
Nihon Genshiryoku Gakkai-Shi ATOMO, 60(2), p.111 - 115, 2018/02
no abstracts in English
Zheng, X.; Tamaki, Hitoshi; Shiotsu, Hiroyuki; Sugiyama, Tomoyuki; Maruyama, Yu
Proceedings of Asian Symposium on Risk Assessment and Management 2017 (ASRAM 2017) (USB Flash Drive), 11 Pages, 2017/11
Tamaki, Hitoshi; Hamaguchi, Yoshikane; Yoshida, Kazuo; Muramatsu, Ken
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 6 Pages, 2005/10
A PSA procedure for MOX fuel fabrication facilities is being developed at the JAERI. This procedure consists of four steps, which are hazard analysis, accident scenario analysis, frequency evaluation and consequence evaluation. The proposed procedure is characterized by the hazard analysis step. The Hazard analysis step consists of two sub-steps. In the first sub-step, a variety of functions of equipment composing the facility are analyzed to identify potential abnormal events exhaustively. In the second sub-step, these potential events are screened to select abnormal events by using a risk matrix based on the rough estimation of likelihood and maximum unmitigated release of radioactive material. One of the unique technical issues in this research is the estimation of likelihood of criticality event. A method is also proposed as a part of PSA procedure taking into consideration of failure of a computerized control system for MOX powder handling process. The applicability of the PSA procedure was demonstrated through the trial application of it to a model plant of MOX fuel fabrication facility.
Ishihara, Masahiro; Futakawa, Masatoshi
JAERI-Data/Code 97-054, 67 Pages, 1997/12
no abstracts in English
W.Nixon*; P.J.Cooper*; C.M.Bone*; S.Acharya*; U.Baeverstam*; J.Ehrhardt*; I.Hasemann*; Steinhauer, C.*; E.G.Diaz*; J.C.Glynn*; et al.
EUR-15109, 0, 338 Pages, 1994/00
no abstracts in English
; ; ;
Nihon Genshiryoku Gakkai-Shi, 27(1), p.56 - 65, 1985/00
Times Cited Count:1 Percentile:24.00(Nuclear Science & Technology)no abstracts in English
;
JAERI-M 84-055, 454 Pages, 1984/03
no abstracts in English
Muramatsu, Ken; Kubo, Kotaro; Takada, Tsuyoshi
no journal, ,
no abstracts in English