scholarly journals A New Method for Estimating Elastic Parameters of Clay Rock Host Rock in Geological Disposal of High-Level Radioactive Waste in China

2021 ◽  
Vol 290 ◽  
pp. 02010
Author(s):  
Geng Wei Rao ◽  
Xiao Dong Liu ◽  
Hai An Liang ◽  
Ping Hui Liu
Keyword(s):  
Parameter Estimation ◽  
Elastic Modulus ◽  
Radioactive Waste ◽  
Estimation Method ◽  
Maximum Error ◽  
Elastic Parameter ◽  
Clay Rock ◽  
High Level Radioactive Waste ◽  
Parameter Estimation Method ◽  
High Level

Taking the clay rock from the Tamusu pre-selected area of China’s high-level radioactive waste geological repository as the research background. Using the methods of triaxial compression testing, X-ray diffraction and microscopic analysis, the main mineral composition, structure and mechanical properties of clay rock under different confining pressures were systematically obtained. Combined with the classical elastic parameter estimation methods at home and abroad, the elastic modulus of the clay rock in the Tamusu pre-selected area is estimated. It finds that the classical elastic parameter estimation method has a large error with the actual test value when calculating the elastic modulus of Tamusu clay rock. The maximum error can reach 788%, and the error decreases with the increase of confining pressure, however, the minimum error is still also 46%. In order to establish the deformation evaluation index suitable for the clay rock in the Tamusu pre-selected area of high-level radioactive waste, considering the influence of the mineral properties and structure of the clay rock on the macro-mechanics properties, a new method for estimating the elastic parameters of the clay rock was established. Compared with the classic elastic parameter estimation method, the maximum error is reduced to 33% and the minimum error is only 2%. Therefore, we suggest that the new elastic parameter estimation method proposed here may be used to evaluate and predict the elastic modulus parameters of the clay rock in the Tamusu pre-selected area for geological disposal of high-level radioactive waste in China.

scholarly journals Identification and evaluation of processes for joint disposal of high level radioactive waste and low to intermediate level radioactive waste

2021 ◽  
Vol 1 ◽  
pp. 183-184
Author(s):  
Andreas Poller ◽  
Susie M. L. Hardie ◽  
Gerhard Mayer ◽  
Marie Pijorr ◽  
Joachim Poppei ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
Selection Procedure ◽  
Crystalline Rock ◽  
Intermediate Level ◽  
Clay Rock ◽  
High Level Radioactive Waste ◽  
Quantitative Analyses ◽  
Intermediate Level Radioactive Waste ◽  
High Level ◽  
Qualitative Analyses

Abstract. The on-going research project „Identification and evaluation of processes that can arise by disposing of both high level radioactive waste (HAW) and low to intermediate level radioactive waste (LAW/MAW) at the same site“ (GemEnd, FKZ 4719F10401), commissioned by the Federal Office for the Safety of Nuclear Waste Management (BASE), is concerned with the question which thermal, hydraulic, mechanical, chemical and biological (THMCB) processes could be of importance for the long-term safety of the geological repository for high level radioactive waste. The focus of the project is on mutual influences between the HAW and LAW/MAW repositories, which should be constructed separately according to the Safety Regulations (Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, BMU, 2020). A second point of emphasis is on processes that could result from the disposal of small amounts of LAW/MAW within the HAW repository. The analyses carried out for each of the potential host rocks clay rock, rock salt and crystalline rock as well as for a combination of clay rock above crystalline rock at a generic site are divided into a qualitative and a quantitative part. As for the qualitative analyses, all potentially relevant processes are identified and evaluated as to whether they are negligible or principally relevant for the exemplary repository configurations considered and according to the current state of knowledge. With regard to the quantitative analyses, the possible extent of potentially safety-relevant processes is illustrated by means of coupled numerical simulations. Of special interest are the effects of particularly sensitive model approaches and/or parameters and notably of the distances between the HAW and LAW/MAW repositories in the different exemplary repository configurations considered. From the results of the quantitative and qualitative analyses, knowledge gaps will be identified and the possibility of their reduction by research and development activities will be discussed. Furthermore, aspects of the transferability of the results to the German site selection procedure will be illuminated. At the interdisciplinary research symposium safeND selected preliminary results of both the qualitative and quantitative analyses will be presented.

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