HR: 0800h
AN: H41E-0830    [Abstracts]
TI: Study on Potential Changes in Geological and Disposal Environment Caused by 'Natural Phenomena' on a HLW Disposal System
AU: * Kawamura, M
EM: kawamura.makoto@jaea.go.jp
AF: Japan Atomic Energy Agency, 4-33 Muramatsu, Tokai-mura, 319-1194, Japan
AU: Umeda, K
EM: umeda.koji@jaea.go.jp
AF: Japan Atomic Energy Agency, 4-33 Muramatsu, Tokai-mura, 319-1194, Japan
AU: Ohi, T
EM: ohi.takao@jaea.go.jp
AF: Japan Atomic Energy Agency, 4-33 Muramatsu, Tokai-mura, 319-1194, Japan
AU: Ishimaru, T
EM: ishimaru.tsuneari@jaea.go.jp
AF: Japan Atomic Energy Agency, 4-33 Muramatsu, Tokai-mura, 319-1194, Japan
AU: Niizato, T
EM: niizato.tadafumi@jaea.go.jp
AF: Japan Atomic Energy Agency, 4-33 Muramatsu, Tokai-mura, 319-1194, Japan
AU: Yasue, K
EM: yasue.kenichi@jaea.go.jp
AF: Japan Atomic Energy Agency, 4-33 Muramatsu, Tokai-mura, 319-1194, Japan
AU: Makino, H
EM: makino.hitoshi@jaea.go.jp
AF: Japan Atomic Energy Agency, 4-33 Muramatsu, Tokai-mura, 319-1194, Japan
AB: We have developed a formal evaluation method to assess the potential impact of natural phenomena (earthquakes and faulting; volcanism; uplift, subsidence, denudation and sedimentation; climatic and sea-level changes) on a High Level Radioactive Waste (HLW) Disposal System. In 2000, we had developed perturbation scenarios in a generic and conservative sense and illustrated the potential impact on a HLW disposal system. As results of the development of perturbation scenarios, two points were highlighted for consideration in subsequent work: improvement of the scenarios from the viewpoints of reality, transparency, traceability and consistency and avoiding extreme conservatism. Subsequently, we have thus developed a new procedure for describing such perturbation scenarios based on further studies of the characteristics of these natural perturbation phenomena in Japan. The approach to describing the perturbation scenario is effectively developed in five steps: Step 1: Description of potential process of phenomena and their impacts on the geological environment. Step 2: Characterization of potential changes of geological environment in terms of T-H-M-C (Thermal - Hydrological - Mechanical - Chemical) processes. The focus is on specific T-H-M-C parameters that influence geological barrier performance, utilizing the input from Step 1. Step 3: Classification of potential influences, based on similarity of T-H-M-C perturbations. This leads to development of perturbation scenarios to serve as a basis for consequence analysis. Step 4: Establishing models and parameters for performance assessment. Step 5: Calculation and assessment. This study focuses on identifying key T-H-M-C process associated with perturbations at Step 2. This framework has two advantages. First one is assuring maintenance of traceability during the scenario construction processes, facilitating the production and structuring of suitable records. The second is providing effective elicitation and organization of information from a wide range of investigations of earth sciences within a performance assessment context. In this framework, scenario development work proceeds in a stepwise manner, to ensure clear identification of the impact of processes associated with these phenomena on a HLW disposal system. Output is organized to create credible scenarios with required transparency, consistency, traceability and adequate conservatism. In this presentation, the potential impact of natural phenomena in the viewpoint of performance assessment for HLW disposal will be discussed and modeled using the approach.
UR: http://www.jaea.go.jp/
DE: 1816 Estimation and forecasting
DE: 1832 Groundwater transport
DE: 1849 Numerical approximations and analysis
DE: 1873 Uncertainty assessment (3275)
DE: 1894 Instruments and techniques: modeling
SC: Hydrology [H]
MN: 2007 Fall Meeting