scholarly journals Experimental Investigation of Thermal Cracking and Permeability Evolution of Granite with Varying Initial Damage under High Temperature and Triaxial Compression

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Xiangxi Meng ◽  
Weitao Liu ◽  
Tao Meng
Keyword(s):  
High Temperature ◽  
Critical Temperature ◽  
Waste Disposal ◽  
Sharp Increase ◽  
Triaxial Compression ◽  
Thermal Cracking ◽  
High Level Waste ◽  
Permeability Evolution ◽  
Initial Damage ◽  
High Level

Thermal cracking and permeability evolution of granite under high temperature and triaxial compression are the key to designing high-level waste disposal sites. In this paper, uniaxial compression tests of granite specimens with different axial compression are designed, and then a solid-head-designed coupling triaxial testing system is applied to study thermal cracking and permeability evolution of granite specimen with different damage at different inlet gas pressures (1, 2, 4, and 6 MPa) and temperatures (ranging from 100 to 650°C). The test results show that granite, nearly impermeable rocks, can show a striking increase of permeability by heating beyond the critical temperature. When the initial axial pressure is 60% or 70% of the uniaxial compressive strength, the growth of granite permeability exhibits three stages during 100∼650°C heating process. Permeability increases by two orders of magnitude, but it does not reach the maximum value (i.e., a network of interconnected cracks is not fully formed in the specimen). With increasing initial damage, permeability shows a sharp increase. Permeability increases by three orders of magnitude, it is in equilibrium state, and a network of interconnected cracks is fully formed in the specimen. Permeability of granite has a critical temperature at which permeability increases sharply. When the temperature is lower than the critical temperature, the magnitude of permeability is 10−18 m2 with a slight increase. When temperature is higher than the critical temperature, the magnitude of permeability is 10−15 m2 with a sharp increase. The critical temperature is related to the initial damage of specimen, and the critical temperature is smaller with the initial damage going larger. Therefore, studying thermal cracking and permeability evolution of granite with different initial damage under high temperature and triaxial compression is expected to provide necessary and valuable insight into the design and construction of high-level waste disposal structures.

THE USE OF CERAMIC SPONGES FOR HIGH LEVEL WASTE DISPOSAL

1964 ◽  
pp. 543-571
Author(s):  
C.W. CHRISTENSON ◽  
R.G. THOMAS ◽  
W.H. ADAMS ◽  
E.B. FOWLER ◽  
G.D. KELLY
Keyword(s):  
Waste Disposal ◽  
High Level Waste ◽  
High Level

Geological Disposal for High-Level Waste: Ethical Considerations

2001 ◽  
Author(s):  
Gustaaf C. Cornelis
Keyword(s):  
Time Scales ◽  
Waste Disposal ◽  
High Level Waste ◽  
Ethical Considerations ◽  
Technical Aspects ◽  
Geological Disposal ◽  
High Level

Abstract This paper describes the activities launched at SCK•CEN, intended to explore ethical and other non-technical aspects when dealing with the time scales considered in the high-level waste disposal program. (1) Especially the issues of retrievability and precaution will be focused on philosophically. Many questions will be raised in order to sensitize all stakeholders for the transdisciplinary character of the transgenerational problem at hand.

scholarly journals Impact of Partitioning and Transmutation on LWR High-Level Waste Disposal

2008 ◽  
Vol 45 (1) ◽  
pp. 84-97 ◽  
Author(s):  
Kenji NISHIHARA ◽  
Shinichi NAKAYAMA ◽  
Yasuji MORITA ◽  
Hiroyuki OIGAWA ◽  
Tomohiko IWASAKI
Keyword(s):  
Waste Disposal ◽  
High Level Waste ◽  
High Level ◽  
Partitioning And Transmutation

Multibarrier Copper-Base Containers for High-Level Waste Disposal

1993 ◽  
Vol 104 (2) ◽  
pp. 219-232 ◽  
Author(s):  
Dale T. Peters ◽  
Konrad J. A. Kundig ◽  
David F. Medley ◽  
Paul A. Enders
Keyword(s):  
Waste Disposal ◽  
High Level Waste ◽  
Copper Base ◽  
High Level

scholarly journals A citizens workgroup helps researchers reflect on their work

2021 ◽  
Vol 1 ◽  
pp. 211-213
Author(s):  
Roman Seidl ◽  
Cord Drögemüller ◽  
Pius Krütli ◽  
Clemens Walther
Keyword(s):  
Waste Disposal ◽  
Personal Experience ◽  
Point Of View ◽  
Academic Disciplines ◽  
High Level Waste ◽  
Value Similarity ◽  
Social Sciences And Humanities ◽  
Mediating Role ◽  
State Of Research ◽  
High Level

Abstract. In our transdisciplinary project (http://www.transens.de) several academic disciplines work on questions and solutions for high-level nuclear waste disposal in Germany. Adding to this interdisciplinary setting, in our sub-project on trust, we have enlisted a group of 16 citizens (citizens workgroup, CWG), reflecting with us on our research with regard to research questions and approaches. In this talk, we present results from a joint workshop of researchers and the CWG on the role of trust in scientists. We want to understand how participants perceive and relate to science and how this may affect trust in scientists and experts. During a first workshop (conducted online in March 2021), the CWG members were allocated to three breakout groups (1)–(3) to discuss three guiding questions: a. What expectations do you have of a scientist from Social Sciences and Humanities (SSH)/Natural Sciences and Engineering (NSE) in the TRANSENS project? b. What characterizes a scientist from SSH/NSE that you trust? c. What would have to happen for you to no longer trust him/her? The group in breakout room (1) was asked to answer questions (a)–(c) for a fictitious SSH researcher. The group in breakout room (2) was asked to do the same for a fictitious NSE researcher. The group in breakout room (3) was asked whether they perceived differences in the trust of SSH and NSE researchers. For SSH we found that a scientist should be sympathetic and non-condescending, represent a neutral point of view, and consider all opinions. Remarkably, discussants in this group struggled to define a role for SSH scientists in high-level waste disposal research. Some participants ascribed SSH a moderating or mediating role. If necessary (e.g. communication of results), mediation between the NSE and the public can be added. SSH scientists may train other scientists with regard to their performance. Participants stated that scientists from NSE should present information in full and clarify the current state of research (provisional nature of knowledge acknowledged). A scientist should not conceal any information, uncertainties, or risks, be neutral and objective, have experience in the field (professionalism, experience, reputation), and not exclusively reproduce one's own opinion or spread untruths. In all groups, participants judged the NSE as “harder”, more serious and more tangible. It was also discussed that the scientist's appearance is of great importance and that a scientist can “pick up” the audience in an exciting way when communicating. Personal experience was mentioned several times in all groups as a basis for trust. These results match findings on the effect of value similarity (Siegrist et al., 2000, and own survey in 2020 in Germany): If a person is perceived as advocating similar values, it is more likely that I trust that person. Personal experience of – among other issues – similar values may increase trust. Moreover, and importantly, trust also emerges when participants know exactly how issues will be considered, e.g. if input from the CWG is considered or not – and if not: why? In general, participants want to be taken seriously. Thus, transparent and binding rules for all participants may be key for a relationship of trust.

Transparent Tools for Uncertainty Analysis in High Level Waste Disposal Facilities Safety

2007 ◽  
Author(s):  
Francisco Luiz de Lemos ◽  
Karl-Heinz Helmuth ◽  
Terry Sullivan
Keyword(s):  
Fuzzy Logic ◽  
Uncertainty Analysis ◽  
Waste Disposal ◽  
Computational Models ◽  
Cognitive Mapping ◽  
Data Interpretation ◽  
High Level Waste ◽  
Rock Interaction ◽  
And Migration ◽  
High Level

In this paper some results of a further development of a technical cooperation project, initiated in 2004, between the CDTN/CNEN, The Brazilian National Nuclear Energy Commission, and the STUK, The Finnish Radiation and Nuclear Safety Authority, are presented. The objective of this project is to study applications of fuzzy logic, and artificial intelligence methods, on uncertainty analysis of high level waste disposal facilities safety assessment. Uncertainty analysis is an essential part of the study of the complex interactions of the features, events and processes, which will affect the performance of the HLW disposal system over the thousands of years in the future. Very often the development of conceptual and computational models requires simplifications and selection of over conservative parameters that can lead to unrealistic results. These results can mask the existing uncertainties which, consequently, can be an obstacle to a better understanding of the natural processes. A correct evaluation of uncertainties and their rule on data interpretation is an important step for the improvement of the confidence in the calculations and public acceptance. This study focuses on dissolution (source), solubility and sorption (sink) as key processes for determination of release and migration of radionuclides. These factors are affected by a number of parameters that characterize the near and far fields such as pH; temperature; redox conditions; and other groundwater properties. On the other hand, these parameters are also consequence of other processes and conditions such as water rock interaction; pH and redox buffering. Fuzzy logic tools have been proved to be suited for dealing with interpretation of complex, and some times conflicting, data. For example, although some parameters, such as pH and carbonate, are treated as independent, they have influence in each other and on the solubility. It is used the technique of fuzzy cognitive mapping is used for analysis of effects of variations on one parameter on the others in a system. This technique uses the concept of fuzzy sets to represent the “quality” of the relation between parameters rather then deterministic numbers.

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