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Abe, Takeyasu; Iida, Yoshihisa
Journal of Advanced Concrete Technology, 20(3), p.236 - 253, 2022/03
Times Cited Count：2 Percentile：13.23(Construction & Building Technology)This paper is a state-of-the-art report on the performance assessment of cementitious and related materials as components of engineered barrier systems for radioactive waste management. In this paper, (1) the concept of safety functions is reviewed as the engineering background of discussion, (2) an overview of the postclosure performance assessment for Belgian low- and intermediate-level short-lived radioactive waste disposal is provided, and (3) a modeling methodology for engineered barrier systems is analyzed using the concept of "mandala for durability mechanics". According to these works, authors present technical suggestions for technical stakeholders of Japanese low-level radioactive waste disposal.
Sasagawa, Tsuyoshi; Mukai, Masayuki; Sawaguchi, Takuma
JAEA-Data/Code 2021-012, 122 Pages, 2022/01
JAEA-Data-Code-2021-012.pdf:3.87MB
Reducing public dose is required when radioactive wastes such as high-level and from reactor core internals etc. are disposed of by means of multi barrier system consist of engineered and natural barriers. In these barriers, engineered barrier is expected to bring out confinement function of waste's radionuclides in the barrier. Materials used as the engineered barriers are altered and performances of the barrier materials are degraded in course of time. To estimate properly the degraded performances, analytical evaluation of long-term change of the engineered barrier state is important. Change state of the engineered barrier is given by mass-transport and geochemical-reaction inside the barrier materials and these phenomena are interrelated, it is necessary to calculate the state by means of coupled analysis procedure. We have developed a coupled mass-transport and geochemical-reaction calculation code (MC- BUFFER) to evaluate alteration of engineered barrier specially targeted for water permeability of bentonite buffer material as one of most important performances to engineered barrier. This report describes functions expected for the engineered barrier, influence parameters for the functions, implementation models in MC-BUFFER, structure and functions of MC-BUFFER, input file format and output examples, execution method of MC-BUFFER, and sample run with MC-BUFFER.
Kakehi, Isao; Nakabayashi, Hiroki
JNC TN9400 2000-051, 237 Pages, 2000/04
JNC-TN9400-2000-051.pdf:8.14MB
In this study, we have proposed the concept of safety systems (solutions of safety problems) in pyrochemical reprocessing systems (lt consists of pyrochemical reprocessing methods and the injection casting process for the metal fuel fabrication, or vibro-packing process for the oxide fuel fabrication.) which has different concept from the existing PUREX reprocessing method and pellet fuel fabrication process. And we performed its safety evaluations. FoIlowing the present Japanese safety regulations for reprocessing facilities, we pointed out functions, design requirements and equipments relating to its safety systems and picked up subjects. For the survey of safety evaluations, we first selected anticipated events and accident events, and second by evaluated 6the correspondence of the limitation of the public exposure to the accidents above, by using two parameters, the safety design parameter (the filter performance to confine radioactive matelials) and the leak inventory of radioactivities, and last by picked up its problems. ln addition to the above evaluations we performed basic criticality analyses for its systems to utilize these results for the design and evaluation of the criticality safety management system. Thus this study specified the concept of safety systems for pyrochemical reprocessing processes and then issues in order to establish safety design policies (matters which must consider for the safety design) and guides and to advance more definite safety design.
JNC TN1400 2000-001, 371 Pages, 2000/01
JNC-TN1400-2000-001.pdf:12.26MB
no abstracts in English
*; Seki, Yasushi; Inabe, Teruo; Aoki, Isao
JAERI-M 93-112, 122 Pages, 1993/06
no abstracts in English
*; Nishio, Satoshi; *; Saji, Gen*; Takatsu, Hideyuki; Tada, Eisuke; Aoki, Isao; Seki, Yasushi
Fusion Technology 1992, p.1744 - 1748, 1993/00
no abstracts in English
Mukai, Masayuki; Kataoka, Masaharu; Iida, Yoshihisa; Maeda, Toshikatsu; Hirota, Naoki; Yamaguchi, Tetsuji; Tanaka, Tadao
no journal, ,
Performance evaluation models for engineered barriers and estimation methods for radionuclide migration parameters have been developed to establish a method of long-term safety assessment for geological disposal simulating a variety of environmental conditions of deep underground in Japan. In order to make the safety assessment more systematic and reasonable, the parameters used in radionuclide migration analysis should reflect spatially and temporally changeable conditions of the engineered barriers. Moreover, the changeable conditions should be quantified based on the calculation in which models and parameters for the barrier materials are systematically linked with each other. In this study, a sequence of the systemized procedure was configured and was tested to pick out parameters having significant influence to the safety function of the buffer material from results of long-term performance analysis on engineered barrier system.
