Evolution of the reaction and alteration of granite with Ordinary Portland cement leachates; Sequential flow experiments and reactive transport modelling

Bateman, K.*; 村山 翔太*; 花町 優次*; Wilson, J.*; 瀬田 孝将*; 天野 由記; 久保田 満*; 大内 祐司*; 舘 幸男

Minerals (Internet), 12(7), p.883_1 - 883_20, 2022/07

https://doi.org/10.3390/min12070883

The construction of a repository for geological disposal of radioactive waste will include the use of cement-based materials. Following closure, groundwater will saturate the repository and the extensive use of cement will result in the development of a highly alkaline porewater, pH 12.5; this fluid will migrate into and react with the host rock. The chemistry of the fluid will evolve over time, initially high [Na] and [K], evolving to a Ca-rich fluid, and finally returning to the groundwater composition. This evolving chemistry will affect the long-term performance of the repository, altering the physical and chemical properties, including radionuclide behaviour. Understanding these changes forms the basis for predicting the long-term evolution of the repository. This study focused on the determination of the nature and extent of the chemical reaction, as well as the formation and persistence of secondary mineral phases within a granite, comparing data from sequential flow experiments with the results of reactive transport modelling. The reaction of the granite with the cement leachates resulted in small changes in pH and the precipitation of calcium aluminum silicate hydrate (C-(A-)S-H) phases of varying compositions, of greatest abundance with the Ca-rich fluid. As the system evolved, secondary C-(A-)S-H phases re-dissolved, partly replaced by zeolites. This general sequence was successfully simulated using reactive transport modelling.

The Impact of cement on argillaceous rocks in radioactive waste disposal systems; A Review focusing on key processes and remaining issues

Wilson, J.*; Bateman, K.; 舘 幸男

Applied Geochemistry, 130, p.104979_1 - 104979_19, 2021/07

https://doi.org/10.1016/j.apgeochem.2021.104979

地層処分概念では、セメント系材料の様々な目的での使用が想定されている。粘土質岩が対象母岩である場合、高アルカリ条件のセメント間隙水が、粘土質岩中の主要鉱物を不安定化させ、セメントと岩石の境界部に変質領域を生じさせる。文献のレビューにより、実験研究、アナログ研究及びモデル化研究から得られるプロセスの理解の現状と、残された課題が抽出された。セメントと粘土質岩の相互作用で生じる鉱物の変遷プロセスについて理解が進んでいるものの、今後の課題として、処分環境に近い温度条件でのセメントと粘土質岩の変遷プロセス、二次鉱物生成の反応速度、二次鉱物生成に伴う間隙閉塞、変質が放射性核種の移行に及ぼす影響などが特定された。

Experimental tests of paleoclassical transport

Callen, J. D.*; Anderson, J. K.*; Arlen, T. C.*; Bateman, G.*; Budny, R. V.*; 藤田 隆明; Greenfield, C. M.*; Greenwald, M.*; Groebner, R. J.*; Hill, D. N.*; et al.

Nuclear Fusion, 47(11), p.1449 - 1457, 2007/11

https://doi.org/10.1088/0029-5515/47/11/006

最近開発されたパレオクラシカル輸送モデルが多数のトロイダルプラズマ装置のデータと比較された。DIII-D, Alcator C-MOD, NSTXのオーム加熱レベルのプラズマ,RTPの電子サイクロトロン波加熱プラズマ,JT-60Uの強い電子内部輸送障壁プラズマ,MST逆磁場ピンチ,SSPXスフェロマックの実験データを用いた。モデルから予想される径方向の電子熱輸送は、オーム加熱レベルの幅広い実験結果と一致し、2倍程度の誤差で電子熱輸送の下限を与えると思われる。

Laboratory Examination of Microbial Perturbations in a Granitic Environment

West, J. M.*; 濱 克宏; Bateman, K.*; Coombs, P.*; Hards, V.*; Milodowski, A. E.*; Wetton, P. D.*; 吉田 英一

Materials Research Society Symposium Proceedings, Vol.663, p.657 - 664, 2002/00

地下深部に存在する微生物(硫酸還元菌・鉄還元菌)が、地下水-岩石反応に与える影響を把握するために、スウェーデン地下研究施設で採取した微生物、地下水、岩石(閃緑岩)を利用して、実験室でのカラム式反応試験を実施した。その結果、微生物活動によると考えられる粘土鉱物(スメクタイト)の生成が確認された。

Laboratory work to examine microbial effects on redox and quantification of the effects of microbiological perturbations on the geological disposal of HLW (TRU)

吉田 英一; 濱 克宏; West, J. M.*; Bateman, K.*; Milodowski, A. E.*; Baker, S. J.*; Coombs, P.*; Hards, V. L.*; Spiro, B.*; Wetton, P. D.*

JNC TJ7400 99-013, 68 Pages, 1999/07

JNC-TJ7400-99-013.pdf:3.15MB

None

Reaction and alteration of mudstone with cement pore fluids

Bateman, K.; 天野 由記; 舘 幸男

no journal, , 

The construction of a repository for the geological disposal of nuclear waste will include the use of cement-based materials. Following closure, groundwater will saturate the repository and the use of cement will result in the development of a highly alkaline porewater in the case of Ordinary Portland cement (OPC). The alkaline fluid will migrate and react with the host rock, affecting the long-term performance of the repository altering the physical and chemical properties, including radionuclide behaviour. This study focused on the alteration due to OPC-type leachates on mudstone, a potential candidate host rock in Japan. A series of batch (to provide long-term equilibrium data) and flow experiments (to provide spatial and temporal data) were conducted inside a Nitrogen gas atmosphere glove box, with Horonobe mudstone, and simplified OPC leachates. Fluid analysis was by Inductively Coupled Plasma (ICP) and Ion Chromatography (IC), and determination of pH, and Eh. Solids were examined by scanning electron microscopy (SEM). In summary, the reaction of the mudstone with OPC type fluids demonstrated that long term, the chemical buffering capacity leading to a reduction in the pH of the leached fluid and the precipitation of CSH phases. This is consistent with previous similar studies, though this study suggests that the presence of pyrite in the Horonobe mudstone could result in an acidic pulse could precede the alkaline fluid in this host rock.

The Impact of cement on argillaceous rocks in radioactive waste disposal systems; An Overview of research needs, and ongoing work being undertaken in Japan

Wilson, J.*; Bateman, K.*; 川間 大介*; 舘 幸男

no journal, , 

Several repository concepts have been proposed for the disposal of radioactive wastes, some of which include argillaceous (clay-rich) host rocks and cementitious engineered barriers. The presence of hyperalkaline cement pore-fluid results in the destabilization of primary minerals in argillaceous rocks, leading to alteration at the interface between cement/concrete and repository host rock. This phenomenon has implications for radionuclide transport and safety assessment. A general review of key data on cement-mudrock interactions has been undertaken as part of a programme of research in Japan, with experimental, analogue, and modelling studies being considered. Although a reasonably good understanding of the key processes has been acquired, with expected features of cement-mudrock interfaces being identified, there are some areas in which a degree of uncertainty remains. These include alteration under elevated temperature conditions, the kinetics of secondary mineral growth, the extent of pore clogging, and radionuclide mobility. In addition to the recent review, work is being undertaken in Japan to further the understanding of cement-mudrock interactions, including: in situ experiments, laboratory experiments, and their simulation. This work demonstrates the progress made within the Japanese programme and suggests areas where further work may be beneficial.