Enhancement of the methodology of repository design and post-closure performance assessment for preliminary investigation stage, 3; Progress report on NUMO-JAEA collaborative research in FY2013 (Joint research)

Shibata, Masahiro; Sawada, Atsushi; Tachi, Yukio; Makino, Hitoshi; Wakasugi, Keiichiro; Mitsui, Seiichiro; Kitamura, Akira; Yoshikawa, Hideki; Oda, Chie; Ishidera, Takamitsu; et al.

JAEA-Research 2014-030, 457 Pages, 2015/03

JAEA-Research-2014-030.pdf:199.23MB

JAEA and NUMO have conducted a collaborative research work which is designed to enhance the methodology of repository design and post-closure performance assessment in preliminary investigation stage. With regard to (1) study on rock suitability in terms of hydrology, based on some examples of developing method of hydro-geological structure model, acquired knowledge are arranged using the tree diagram, and model uncertainty and its influence on the evaluation items were discussed. With regard to (2) study on scenario development, the developed approach for "defining conditions" has been reevaluated and improved from practical viewpoints. In addition, the uncertainty evaluation for the effect of use of cementitious material, as well as glass dissolution model, was conducted with analytical evaluation. With regard to (3) study on setting radionuclide migration parameters, based on survey of precedent procedures, multiple-approach for distribution coefficient of rocks was established, and the adequacy of the approach was confirmed though its application to sedimentary rock and granitic rock. Besides, an approach for solubility setting was developed including the procedure of selection of solubility limiting solid phase. The adequacy of the approach was confirmed though its application to key radionuclides.

Advancing an evaluation methodology to assess the potential effects of uplift, erosion, and climate and sea-level changes on HLW disposal; Modeling geomorphic change caused by fluvial erosion in Japan

Shimemoto, Hidenori; Yamaguchi, Masaaki; Wakasugi, Keiichiro; Shibata, Masahiro

JAEA-Research 2013-012, 35 Pages, 2013/10

JAEA-Research-2013-012.pdf:8.16MB

In this study, we focus on uplift and erosion and climatic and sea-level changes among natural phenomena and pick up fluvial erosion is main and means large velocity between different type of erosion in Japan, and developed conceptual modeling of geomorphic change due to fluvial erosion with respect to fluvial erosion and sedimentation system, to evaluate the potential impact of exposure case of high level radioactive waste to land surface. Conceptual modeling of geomorphic change caused by fluvial erosion is developed with riverhead and downriver, such catchment areas are not treated until now, by conceptualization of geomorphic change on river due to uplift and denudation and climatic and sea-level changes for about last hundred and twenty thousand years. Furthermore, we analysis the depth and width of deepening and lateral erosion around river channel using the data of alluvium and show an example of the setup method concerning dimension on conceptual model to estimate the erosion volume contribute to the evaluation as to high level radioactive waste exposure process to land surface. We illustrate by an example the dimension as to valley within the central Japanese mountains using DEM data on conceptual model at riverhead. We develop conceptual modeling of geomorphic change on the basis of the feature on fluvial erosion in Japan and set basic intelligence to evaluate the potential impact of repository exposure to land surface caused by fluvial erosion, based on above study.

Study on relationship between multiple safety functions in the engineered barrier system

Wakasugi, Keiichiro; Koo, Shigeru*; Shibata, Masahiro

JAEA-Research 2011-006, 31 Pages, 2011/06

JAEA-Research-2011-006.pdf:2.37MB

Although confirmation of the long-term safety of the constructed geological disposal system has been conducted by using scenario, model and data according to the internationally agreed methodology, there were a few researches that focused on individual safety functions and their relationships. This is because multiple safety functions are a fundamental concept for ensuring the safety of the geological disposal, and the long-term safety is accomplished by the whole system. Therefore, we developed a methodology to identify performance of the individual safety functions and their relationships considering the characteristic of the multiple safety functions, and examined the safety functions in the engineered barrier system based on this methodology. The results from this study are useful for constructing design requirements for the system components of the geological disposal as well as developing repository concept.

Horonobe Underground Research Laboratory project synthesis of phase I investigation 2001-2005 volume "Geological Disposal Research"

Fujita, Tomoo; Taniguchi, Naoki; Matsui, Hiroya; Tanai, Kenji; Nishimura, Mayuka; Kobayashi, Yasushi; Hiramoto, Masayuki; Maekawa, Keisuke; Sawada, Atsushi; Makino, Hitoshi; et al.

JAEA-Research 2007-045, 140 Pages, 2007/03

JAEA-Research-2007-045-1.pdf:38.33MB
JAEA-Research-2007-045-2.pdf:44.62MB

This report summarizes the progress of research and development on geological disposal during the surface-based investigation phase (2001-2005) in the Horonobe Underground Research Laboratory project (HOR), of which aims are to apply the design methods of geological disposal and mass transport analysis to actual geological environments and derive future subjects based on the results. The design methods of geological disposal were reviewed based on the recent knowledge and the advertences were identified. Then the parameters for virtual design of engineered barrier system, backfill deposition hole and tunnel were set up based on actual geological conditions obtained from the surface-based investigations in HOR as an example of actual geological environment. The conceptual structure from site investigation and evaluation to mass transport analysis was represented as a work flow at first. Then following this work flow a series of procedures for mass transport analysis were carried out based on actual geological conditions obtained from the surface-based investigations in HOR to illustrate the functioning of the work flow and the applicability of this methodology. Consequently, knowledge that will help follow-up or future execution and planning activities was obtained.

None

Makino, Hitoshi; Sawada, Atsushi; Maekawa, Keisuke; Shibata, Masahiro; Sasamoto, Hiroshi; Yoshikawa, Hideki; Wakasugi, Keiichiro; Koo, Shigeru*; Hama, Katsuhiro; Kurikami, Hiroshi; et al.

JNC TN1400 2005-021, 148 Pages, 2005/09

JNC-TN1400-2005-021.pdf:32.85MB

None

Development of JNC Geologic Disposal Technical Information Integration System -An Approach to Integrate and Share Technical Information among Safety Assessment, Repository Design and Site Investigation

Uchida, Masahiro; Makino, Hitoshi; Wakasugi, Keiichiro; Shibata, Katsushi

OECD/NEA Amigo Project Dai-1-Kai Wakushoppu, 0 Pages, 2003/00

None

Neutronics analysis of the ITER NB system; Nuclear responses of the components and shutdown dose around the NB injector

Shibata, Keiichiro*; Maki, Koichi*; Inoue, Takashi*; Hanada, Masaya; Okumura, Yoshikazu; Yamashita, Y.*

Fusion Engineering and Design, 51-52, p.357 - 362, 2000/11

https://doi.org/10.1016/S0920-3796(00)00263-5

no abstracts in English

Design analysis for reducing dose rate in the NBI to realize direct access by workers for a fusion experimental reactor

Inoue, Takashi; *; *; Yamashita, Y.*

Fusion Technology 1996, 0, p.1799 - 1802, 1996/00

no abstracts in English

An Approach to establish information basis of Weathered zone for the safety assessment to HLW disposal over long-term

Shimemoto, Hidenori; Wakasugi, Keiichiro; Shibata, Masahiro; Yamaguchi, Masaaki

no journal, , 

In the safety assessment of radioactive waste disposal, consideration of evolution of geological environment is requested. The disposal facility can be expected to come close to ground surface, when continuous uplift and erosion for long-term is assumed. In general, geological conditions in near-surface underground is different from those in deep-underground due to weathering. Preparing for such scenario and nuclides migration analysis, information regarding weathered zone are surveyed and arranged. As a result, 37data of depth (thickness) of weathered zone were extracted. Then the data distribution and characteristics of thick weathered case was discussed. The relation between weathered zone and landform was also discussed. Categorization into four patterns of the relation are proposed, and factors which contribute to the difference of the patterns are discussed. Regarding the geological property/condition in the weathered zone, quantitative information on hydraulic and chemical conditions is limited, to the contrary data on uniaxial strength and porosity are available. For the sake of condition setting for near-surface underground in the long-term safety assessment, continuous survey of information is important.

Scenario development for the risk-informed safety assessment of geological disposal

Makiuchi, Akie*; Ishida, Keisuke*; Kurosawa, Susumu*; Inagaki, Manabu*; Umeki, Hiroyuki*; Ebashi, Takeshi; Wakasugi, Keiichiro; Makino, Hitoshi; Shibata, Masahiro

no journal, , 

NUMO is developing a safety case for the geological disposal of vitrified high-level radioactive wastes and TRU wastes on the basis of the latest findings. In parallel, JAEA starts to investigate the geological disposal of spent fuel as an alternative disposal option. In such a situation, NUMO and JAEA have jointly established a scenario development method. Since the considerations of both probabilities and influences of scenarios or processes are focused on, the disaggregated approach is adopted. This approach had been recommended by ICRP, and applied to Japanese safety regulations for disposing low-level waste. To efficiently identify processes that may influence geological disposal systems, various supposable processes are analyzed in terms of their probabilities and influences on the safety function by conducting audits using FEP information. One remarkable feature of this method is its demand of high-level traceability of various judgments through analysis and definition of scenarios. Traceability is ensured by various tools and/or products. One such example is a "Safety Function/Variable/Process Diagram", which structurally illustrates interrelations between safety functions, processes and variables of geological disposal systems. This presentation will show the features of the abovementioned method in detail along with some examples of developed scenarios.