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In situ investigation of the redox front above an underground rock cavern and estimation of its moving rate

Published online by Cambridge University Press:  05 July 2018

T. Oyama ,
Y. Inohara  and
T. Nagaoka
T. Oyama*
Affiliation:
Central Research Institute of Electric Power Industry, 1646 Abiko Abiko-shi, Chiba, 270-1194, Japan
Y. Inohara
Affiliation:
Central Research Institute of Electric Power Industry, 1646 Abiko Abiko-shi, Chiba, 270-1194, Japan
T. Nagaoka
Affiliation:
Central Research Institute of Electric Power Industry, 1646 Abiko Abiko-shi, Chiba, 270-1194, Japan
*
*E-mail: ooyama@criepi.denken.or.jp
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Abstract

An investigation and evaluation of the redox conditions around an underground rock cavern are important from the viewpoint of the safety assessment of the subsurface geological disposal of radioactive wastes. The in situ redox conditions around a cavern excavated in Neogene pyroclastic rocks were investigated. Rock samples were collected from a tunnel wall crossing the oxidation front, and the properties of pore water seeping into small holes drilled in the tunnel wall were determined. Chemical analysis of the rock samples revealed that pyrite-bearing rocks belowthe oxidation front were oxidized by the dissolved oxygen in the groundwater infiltrating from the surface. The water properties changed with increasing oxidation of the rocks. From the amount of oxygen-consuming components in the rocks, the migration rate of the oxidation front was estimated to be ~0.2 mm/y due to the flowrate of groundwater (0.1 m/y) containing oxygen.

Keywords

subsurface geological disposalradioactive wastesredox frontpyriteoxidation rate
Type
Research Article
Information
Mineralogical Magazine , Volume 72 , Issue 1 , February 2008 , pp. 107 - 109
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2008

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