Integration of the geological survey data obtained for shaft and gallery walls from the surface to a depth of 380m in the Horonobe Underground Research Laboratory Project

Sakai, Toshihiro; Hayano, Akira

JAEA-Data/Code 2021-010, 243 Pages, 2021/10

JAEA-Data-Code-2021-010.pdf:62.15MB
JAEA-Data-Code-2021-010-appendix1(CD-ROM).zip:95.55MB
JAEA-Data-Code-2021-010-appendix2(CD-ROM).zip:152.69MB
JAEA-Data-Code-2021-010-appendix3(CD-ROM).zip:25.48MB

The Horonobe Underground Research Laboratory (URL) Project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of relevant disposal technologies through investigations of the deep geological environment within the host sedimentary formations at Horonobe, northern Hokkaido. The project consists of two major research areas, "Geoscientific Research" and "R&D on Geological Disposal", and proceeds in three overlapping phases, "Phase I: Surface-based investigation", "Phase II: Construction" and "Phase III: Operation". The geological survey has been carried out at the shafts and the galleries in the Phase II. The geological survey was carried out during the excavation cycle, and the data were obtained for each an excavation cross section. This report shows the data which the individual geological data were integrated for the geological survey at the shafts and the galleries from the surface to a depth of 380m.

Basic properties of the concrete using the low alkaline cement (HFSC) developed by JAEA

Seno, Yasuhiro*; Nakayama, Masashi; Sugita, Yutaka; Tanai, Kenji; Fujita, Tomoo

JAEA-Data/Code 2016-011, 164 Pages, 2016/11

JAEA-Data-Code-2016-011.pdf:8.45MB
JAEA-Data-Code-2016-011-appendix(CD-ROM).zip:0.1MB

The cementitious materials are used as candidate materials for the tunnel support of the deep geological repository of high-level radioactive wastes (HLW).Generally the pH of leachate from concrete mixed Ordinary Portland Cement (OPC) shows a range of 12 to 13. The barrier function of bentonite used as a buffer material and that of host rock might be damaged by the high alkaline leachate from cementitious materials. Therefore, low alkalinity that does not damage each barrier function is necessary for cementitious materials used for the tunnel support system of the HLW geological repository. JAEA has developed a low alkaline cement named as HFSC (Highly Fly-ash contained Silicafume Cement) which the pH of the cement leachate could lower approximately 11. We have confirmed the applicability of HFSC for the tunnel support materials, by using experimentally as the shotcreting materials to the part of gallery wall at 140m, 250m and 350m depth in Horonobe Underground Research Laboratory. And moreover, HFSC has been used as the cast-in-place concrete for the shaft lining concrete at the depth of 374m-380m. This Data/Code summarized the past HFSC mix proportion test results about the fresh concrete properties and hardened concrete properties, in order to offer the information as a reference for selecting the mix proportion of HFSC concrete adopted to the disposal galleries et al. in the future.

In situ diffusion experiment for siliceous mudstone at the Horonobe URL

Ono, Hirokazu; Takeda, Masaki; Ishii, Eiichi; Kawate, Satoshi

no journal, , 

It is necessary to clarify the mass transport behavior in a deep underground natural barrier, for improving the reliability of safety assessment of high-level radioactive waste disposal. In situ mass transport experiments are being conducted for fractures and rock matrices at the G.L. -350 m gallery in the Horonobe Underground Research Laboratory (URL). This study reports an overview and preliminary results of in situ diffusion experiments for rock matrices.

Modeling of solutes transport at the Horonobe URL, 2; Characterization of solutes transport in fractures based on data from in-situ tracer tests

Ono, Hirokazu; Takeda, Masaki; Ishii, Eiichi; Tachi, Yukio

no journal, , 

It is necessary to clarify the mass transport behavior in a deep underground natural barrier, for improving the reliability of safety assessment of high-level radioactive waste disposal. This study reports an analysis using data from in situ tracer tests for fractures in mudstone at Horonobe Underground Research Laboratory (URL).

Evaluation of swelling deformation using buffer material swelling sensor on the full-scale in-situ engineered barrier system experiment

Kimura, Shun; Nakayama, Masashi; Kinota, Kimihiro; Tanai, Kenji; Niunoya, Sumio*; Shimura, Tomoyuki*; Fukaya, Masaaki*

no journal, , 

Swelling deformation of buffer material has been measured using buffer material swelling sensor on the full-scale in-situ engineered barrier system experiment. The sensor consists of strain gauges and is installed between the buffer material and backfill. This study reports the calculation result of the swelling deformation from measured strain values.

Solute transport modelling at the Horonobe URL; Tracer test in the fault zone in mudstone

Murayama, Shota*; Takeda, Masaki; Ono, Hirokazu; Tachi, Yukio

no journal, , 

To evaluate mass transport in a fault zone containing multiple fractures, it is necessary to develop an mass transfer model based on the characteristics of the actual fault zone, and to conduct an in-situ tracer test. It is important to obtain information on the transport path and parameters through the tracer test. This paper presents the results of the tracer test conducted in a fault zone in the 350m research drift of Horonobe URL. The spatial distributions of the fractures and transport paths were evaluated based on the observation of the core sample collected after the tracer test and the tracer concentration analysis on the fracture surface. Furthermore, the transport model was applied and validated thorough the interpretation of the test results.