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Takeda, Nobufumi*; Iriya, Keishiro*; Hitomi, Takashi*; Konishi, Kazuhiro*; Kurihara, Yuji*
Obayashigumi Gijutsu Kenkyushoho (CD-ROM), (72), 8 Pages, 2008/00
To evaluate applicability as the steel reinforced concrete of the concrete with the low alkalinity cement which contains pozzolan that has been examined to apply for high level radioactive waste disposals, concrete of 30% water-cement ratio was performed 6-year marine exposure examination, aging of their compressive strength, the intrusion width of the chloride ion and the corrosion of reinforcing bar were investigated. And based on these results, progress of corrosion of reinforcing bar and the outbreak time of reinforcing corrosion crack were predicted. As a result, the following result became clear. (1) There is no fall of the compressive strength of test pieces in 6-year marine exposure examination. (2) There is little penetration of the chloride ion in comparison with the concrete consists of ordinary Portland cement. (3) The corrosion of reinforcing bar starts for the early stage with a little quantity of chloride ion intrusion, the progress until six years is extremely small. (4) the corrosion speed of the reinforcing bar of concrete with low alkali cement in underground water including sea water were estimated as 0.30
0.55 mg/(cm
year). In case of using this concrete to structure with 100 mm cover thickness and 22 mm reinforcing bar diameter, the outbreak time of reinforcing corrosion crack were predicted as 50100 years after construction.
Nakayama, Masashi; Iriya, Keishiro*; Fujishima, Atsushi; Mihara, Morihiro; Hatanaka, Koichiro; Kurihara, Yuji*; Yui, Mikazu
Materials Research Society Symposium Proceedings, Vol.932, p.159 - 166, 2006/00
Cementitious material is one of candidates of engineered barriers in TRU and HLW repositories. However, since ordinary Portland cement may rises pH of pore water due to its high alkalinity, bentnite and rock which contact with cementitious barriers as a mulch barrier system may deteriorate for a long term by its high pH. Low alkalinity cement with high pozzolanic material content are developed in order to reduce such hyper alkaline deterioration. This paper shows that pH of pore water of this cement is about 11, and that it can be applied for actual structures as self compacting concrete and shotcrete.
Iriya, Keishiro*; Kurihara, Yuji*; Noda, Masaru*
JNC TJ5400 2004-003, 45 Pages, 2005/02
JNC-TJ5400-2004-003.pdf:45.61MB
None
Kurihara, Yuji; Yui, Mikazu; Tanai, Kenji; Kawakami, Susumu; Sugita, Yutaka; Taniguchi, Naoki; Hirai, Takashi
JNC TN8400 2004-006, 59 Pages, 2004/04
JNC-TN8400-2004-006.pdf:5.97MB
Following studies have been done in this papers in order to apply the technologies based on H12 report to the actual geological conditions of Horonobe underground research laboratory. 1.reconsidering the process of repository design, 2. arrangement of the relations between geological conditions and the performance of engineering barrier systems, 3.present the appropriate form of geological informations, 4.study on the stability of deposition hall.
Kurihara, Yuji; Yui, Mikazu; Tanai, Kenji; Kawakami, Susumu; Sugita, Yutaka; Taniguchi, Naoki; Hirai, Takashi
JNC TN8400 2004-002, 58 Pages, 2004/04
JNC-TN8400-2004-002.pdf:2.38MB
In this paper, the items of in-situ experiments at Horonobe URL with respect to the technical issues about reliability of long-term behavior of engineered barrier system were extracted. And the concepts of the experiments were studied from several points of view such as verification of models and getting the actual behavior. Extracted items of the in-situ experiments are as follows. Coupled Phenomena Test (THMC Test), Buffer & Rock Creep Test, Gas Migration Test, Over-pack Corrosion Test, High-pH Influence Test, Low Alkaline Concrete Execution Test, Engineering-Barrier Emplacement Test, Tunnel Plugging Test.
Kurihara, Yuji; Fujita, Tomoo; Kawakami, Susumu; Jintoku, Takashi; Yui, Mikazu; Sugita, Yutaka
JNC TN8400 2003-053, 32 Pages, 2004/03
JNC-TN8400-2003-053.pdf:0.41MB
In previous JNC tequnichal reports, from a view point of long-term safety on geological disposal of high level radioactive waste, the items which should guarantee the performance of each element of the repository were extracted, and it was shown how to guarantee the performance about these items. Furthermore, future R&D requirements were extracted. In this report, the status of each subject in JNC was reported.
Matsui, Hiroya; Kurihara, Yuji; Makino, Hitoshi
JNC TN5400 2003-004, 50 Pages, 2004/03
JNC-TN5400-2003-004.pdf:10.12MB
This report is described for preliminary plan in Phase II and Phase III taken into consideration of expected geological environment at position of URL based on the results of the investigations until FY 2002/2003. The project progress, duration of construction phse and total cost are considered as important factors for planning as well. The below items of in-situ experiments in Phase II and Phase III are planning. [Phase II] (In-situ experiments for understanding of geological environment) *Geological survey at drift face *Inflow measurement in three shafts *Water pressure monitoring and groundwater sampling around a shaft during excavation of URL *Investigation for EDZ around a shaft *Stress measurement on support *Detail investigations for geological environment around 250m drift and 550m drift *Excavation disturbance experiment in a drift *Investigation for desaturation zone and redox condition around a drift. (Engineered barrier system) *In-situ experiment on low-alkari concrete *In-situ experiment for gas migration in engineering barrier system [Phase III] (In-situ experiments for understanding of geological environment) *EDZ experiment for stress interference *Investigation of long-term behavior of EDZ around a drift *Detail investigation on fault/fault zone *Monitoring for the change of geological environment at earthquake *Backfill test in borehole (Engineered barrier system) *T-H-M-C experiment *In-situ experiment for corrosion of overpack *Investigation of the influence of a concrete to engineering barrier system and geological environment *In-situ experiment for interference between backfill material and geological environment *Backfill test in a drift (Safety assessment) *Tracer tests in engineering barrier system, natural barrier and fault/fault ...
Kawakami, Susumu; Yui, Mikazu; Kurihara, Yuji; Jintoku, Takashi; Sugita, Yutaka
JNC TN8400 2003-037, 26 Pages, 2004/02
JNC-TN8400-2003-037.pdf:1.33MB
In order to contribute to the safety standards and guidelines upon which a administration decides, examination for clarifying how to reflect the result obtained by future R&D was performed in other reports, as the JNC technical reports. In those reports, from a viewpoint of the long-term safety on geological disposal of high-level radioactive waste, the items which should guarantee the performance of each element of the repository were extracted, and it was shown how to guarantee the performance about these items. Furthermore, future R&D requirements were extracted. In this report, the status of each subject in JNC was reported.
Sugita, Yutaka; Kawakami, Susumu; Yui, Mikazu; Makino, Hitoshi; Sawada, Atsushi; Mihara, Morihiro; Kurihara, Yuji
Genshiryoku Bakkuendo Kenkyu, 10(1), p.103 - 112, 2004/00
None
Sugita, Yutaka; Kurihara, Yuji; Kawakami, Susumu; Jintoku, Takashi; Yui, Mikazu
JNC TN8400 2003-015, 34 Pages, 2003/05
JNC-TN8400-2003-015.pdf:2.65MB
In order to contribute to the safety standards and guidelines upon which a governmental administration decide, examination for clarifying how to reflect the result obtained by future R&D was performed. From a view point of long-term safety on geological disposal, the items which should guarantee the performance of each element which constitutes disposal institutions (by this report, they are the backfill, the plug, the tunnel, and the pit) were extracted, and it was shown what a performance guarantee is concretely offered about these items. Furthermore, based on H12 report as a situation of present R&D for a method of a performance guarantee, the subjects considered that a future R&D is required were extracted.
Sugita, Yutaka; Kawakami, Susumu; Yui, Mikazu; Makino, Hitoshi; ; Kurihara, Yuji; Mihara, Morihiro
JNC TN8400 2003-010, 44 Pages, 2003/04
Regarding closure technology of undergound facilities in geological disposal of the HLW in H12 rport, the fundamental concept that closure technology has no impact against the engineered barrier system(EBS) was described. Performance Assessment(PA) has been performed without considering of the barrier function of closure elements. Following H12 report, the various in-situ data of the closure elements (ex. plug, backfill) have been obtained. Therefore, we considered that the PA of the EBS considering the expecting performance of the closure elements from the view points of both the engineering technology and the PA should be examined. First, the characteristics of rock mass and the function of the closure elements were summarized. Then, the closure scenario was developed preliminarily based on hydrological analysis between a hydraulic fracture and a disposal panel, the fault tree analysis, and so on.
Kawakami, Susumu; Sugita, Yutaka; Kurihara, Yuji; Jintoku, Takashi; Taniguchi, Naoki; Yui, Mikazu
JNC TN8400 2002-026, 42 Pages, 2003/03
JNC-TN8400-2002-026.pdf:12.1MB
In order to contribute to the safety standards and guidelines upon which a administration decides, examination for clarifying how to reflect the result obtained by future R%D was performed. From a viewpoint of the long-term safety on geological disposal, the items which should guarantee the performance of each element which constitutes disposal institutions (by this report, they are the overpack and the buffer material) were extracted, and it was shown what a performance guarantee is concretely offered about these items. Furthermore, based on the H12 report as a situation of present R&D for a method of a performance guarantee, the subjects considered that a future R&D is required were extracted. Moreover, the items of a safety standard and guideline were assumed, and the relation between these items and a performance guarantee items was arranged. One arrangement for clarifying whether to be reflected in the safety regulations and guidelines whose R%D subjects extracted from the performance guarantee items was shown.
Horita, M.*; ; Okutsu, Kazuo*; Yamamoto, Takuya*; Amemiya, Kiyoshi*
JNC TJ8400 2000-022, 303 Pages, 2000/02
JNC-TJ8400-2000-022.pdf:10.42MB
This report gives supplementary information and discussions on issues of the high-level waste geological disposal study. The following subjects are discussed ; (1)Evaluation of the effects of coefficient of lateral pressure to the specifications of disposal facilities (2)Functional development of remote operational machinery (3)Arrangement of basic data on cost estimation for disposal (4)Understanding of engineering countermeasures to potential phenomena deep under the ground (5)Selection of construction technologies (6)Establishment of the disposal concept under the coasts. For the coefficient of lateral pressure equal to 2, the cross section of disposal drift, the disposal drift spacing, the waste package pitch in the disposal drift and the specification of supporting system are designed. They are compared with those for the case of coefficient of lateral pressure equal to 1. In the case of coefficient of lateral pressure equal to 2, total length of drifts is 1.5 times, and total excavation volume is 1.8 times larger than later case. For the sealing, transportation and emplacement equipment for waste, technology of the fundamental function, remote operation, accidental events and countermeasures are discussed. The plan for developments on those items is proposed. The item of the cost for the construction, operation, and backfilling are discussed. The surface facilities, and, worker arrangement plan are proposed. For the potential phenomena encountered deep under the ground, the countermeasures are investigated form the construction experience, and the future research subjects are discussed for the underground research laboratory. For the construction technologies, the experience of construction management for the tunnel is investigated, and, the research subjects are proposed. For the disposal concept under coasts, rock condition, design condition, construction management, and quality control are compared with the disposal concept under the ground. The ...
Kurihara, Yuji*; Tokunaga, Masahiro*; Miyazaki, Kiyoshi*; Igarashi, H.*; Ono, O.*; Uchiyama, K.*; Kuzutani, Yoko*; Hayami, Takuya*
PNC TJ1201 94-001, 26 Pages, 1994/02
no abstracts in English
Ishii, Takashi*; Kurihara, Yuji*; Sawauchi, Y.*; Sugihara, Yutaka*; Shimabe, Kenichiro*
PNC TJ1449 92-003, 166 Pages, 1992/02
A few analytical study were executed in order to submit predicted answer which would be referred in the PNC's "1992 report". First heat transfer analyses were done in addition to former studies. In case of sedimentary rock and the depth of GL-500m 80 marea will be needed for the layout of each waste form, and in case of crystalline rock and the depth of 1000m 100 m area will be needed. Far field heat transfer analyses were executed under conservative condition of heat transfer coefficient of ground surface is 10 kcal/m h
C. The temperature of ground surface will not get higher than initial temperature. Secondly, analyses were done using "ABAQUS" and "DACSAR" in order to predict settlement of a waste form in buffer material. The predicted. The predicted settlement by ABAQUS is 0.92mm and by DACSAR is 2.70mm. These displacement will be acceptable. Additionally the influence of swelling of overpackage resulted from corrosion of steel was discussed. According to the preliminary analyses for predicting stress of rock around a waste from, 300mm thick buffer material will be not enough to relaxation of the stress but 1000mm thick buffer material will be enough. Technical meetings were held 7 times in order to discuss these analytical results and design of repositories etc.
Kurihara, Yuji*; Tokunaga, Masahiro*; Miyazaki, Kiyoshi*; Makabe, Y.*; Fukaya, Masaaki*; Ono, O.*; Namiki, Kazuto*
PNC TJ1201 92-002, 45 Pages, 1992/02
None
